Example #1
0
    def init(self):
        """Init DAS web server, connect to DAS Core"""
        try:
            self.reqmgr     = RequestManager(lifetime=self.lifetime)
            self.dasmgr     = DASCore(engine=self.engine)
            self.repmgr     = CMSRepresentation(self.dasconfig, self.dasmgr)
            self.daskeys    = self.dasmgr.das_keys()
            self.gfs        = db_gridfs(self.dburi)
            self.daskeys.sort()
            self.dasmapping = self.dasmgr.mapping
            self.dbs_url    = self.dasmapping.dbs_url()
            self.dbs_global = self.dasmapping.dbs_global_instance()
            self.dbs_instances = self.dasmapping.dbs_instances()
            self.dasmapping.init_presentationcache()
            self.colors = {'das':gen_color('das')}
            for system in self.dasmgr.systems:
                self.colors[system] = gen_color(system)
            if  not self.daskeyslist:
                keylist = [r for r in self.dasmapping.das_presentation_map()]
                keylist.sort(key=lambda r: r['das'])
                self.daskeyslist = keylist

        except ConnectionFailure as _err:
            tstamp = dastimestamp('')
            mythr  = threading.current_thread()
            print("### MongoDB connection failure thread=%s, id=%s, time=%s" \
                    % (mythr.name, mythr.ident, tstamp))
        except Exception as exc:
            print_exc(exc)
            self.dasmgr  = None
            self.reqmgr  = None
            self.dbs_url = None
            self.dbs_global = None
            self.dbs_instances = []
            self.daskeys = []
            self.colors  = {}
            self.q_rewriter = None
            return

        # KWS and Query Rewriting failures are not fatal
        try:
            # init query rewriter, if needed
            if self.dasconfig['query_rewrite']['pk_rewrite_on']:
                self.q_rewriter = CMSQueryRewrite(self.repmgr,
                                                  self.templatepage)
        except Exception as exc:
            print_exc(exc)
            self.q_rewriter = None
Example #2
0
 def init(self):
     """Init DAS web server, connect to DAS Core"""
     try:
         self.logcol     = DASLogdb(self.dasconfig)
         self.reqmgr     = RequestManager(self.dburi, lifetime=self.lifetime)
         self.dasmgr     = DASCore(engine=self.engine)
         self.repmgr     = CMSRepresentation(self.dasconfig, self.dasmgr)
         self.daskeys    = self.dasmgr.das_keys()
         self.gfs        = db_gridfs(self.dburi)
         self.daskeys.sort()
         self.dasmapping = self.dasmgr.mapping
         self.dasmapping.init_presentationcache()
         self.colors = {}
         for system in self.dasmgr.systems:
             self.colors[system] = gen_color(system)
         self.sitedbmgr   = SiteDBService(self.dasconfig)
     except Exception as exc:
         print_exc(exc)
         self.dasmgr = None
         self.daskeys = []
         self.colors = {}
         return
     # Start Onhold_request daemon
     if  self.dasconfig['web_server'].get('onhold_daemon', False):
         self.process_requests_onhold()
Example #3
0
 def setUp(self):
     """
     set up stuff
     """
     self.debug  = 0
     dasconfig   = deepcopy(das_readconfig())
     self.dburi  = dasconfig['mongodb']['dburi']
     self.reqmgr = RequestManager(self.dburi)
Example #4
0
    def init(self):
        """Init DAS web server, connect to DAS Core"""
        try:
            self.reqmgr = RequestManager(lifetime=self.lifetime)
            self.dasmgr = DASCore(engine=self.engine)
            self.repmgr = CMSRepresentation(self.dasconfig, self.dasmgr)
            self.daskeys = self.dasmgr.das_keys()
            self.gfs = db_gridfs(self.dburi)
            self.daskeys.sort()
            self.dasmapping = self.dasmgr.mapping
            self.dbs_url = self.dasmapping.dbs_url()
            self.dbs_global = self.dasmapping.dbs_global_instance()
            self.dbs_instances = self.dasmapping.dbs_instances()
            self.dasmapping.init_presentationcache()
            self.colors = {"das": gen_color("das")}
            for system in self.dasmgr.systems:
                self.colors[system] = gen_color(system)
            # get SiteDB from global scope
            self.sitedbmgr = SERVICES.get("sitedb2", None)
            # Start DBS daemon
            if self.dataset_daemon:
                self.dbs_daemon(self.dasconfig["web_server"])
            if not self.daskeyslist:
                keylist = [r for r in self.dasmapping.das_presentation_map()]
                keylist.sort(key=lambda r: r["das"])
                self.daskeyslist = keylist

        except ConnectionFailure as _err:
            tstamp = dastimestamp("")
            mythr = threading.current_thread()
            print "### MongoDB connection failure thread=%s, id=%s, time=%s" % (mythr.name, mythr.ident, tstamp)
        except Exception as exc:
            print_exc(exc)
            self.dasmgr = None
            self.reqmgr = None
            self.dbs_url = None
            self.dbs_global = None
            self.dbs_instances = []
            self.daskeys = []
            self.colors = {}
            self.q_rewriter = None
            return

        # KWS and Query Rewriting failures are not fatal
        try:
            # init query rewriter, if needed
            if self.dasconfig["query_rewrite"]["pk_rewrite_on"]:
                self.q_rewriter = CMSQueryRewrite(self.repmgr, self.templatepage)
        except Exception as exc:
            print_exc(exc)
            self.q_rewriter = None
Example #5
0
class testDAS_RegMgr(unittest.TestCase):
    """
    A test class for the DAS RequestManager
    """
    def setUp(self):
        """
        set up stuff
        """
        self.debug  = 0
        dasconfig   = deepcopy(das_readconfig())
        self.dburi  = dasconfig['mongodb']['dburi']
        self.reqmgr = RequestManager(self.dburi)

    def test_reqmgr(self):
        """Test reqmgr methods"""
        pid  = 1
        kwds = {'uinput':'bla'}
        self.reqmgr.add(pid, kwds)
        result = self.reqmgr.get(pid)
        self.assertEqual(kwds, result)

        self.reqmgr.remove(pid)
        result = self.reqmgr.get(pid)
        self.assertEqual(None, result)
Example #6
0
class DASWebService(DASWebManager):
    """
    DAS web service interface.
    """

    def __init__(self, dasconfig):
        DASWebManager.__init__(self, dasconfig)
        config = dasconfig['web_server']
        self.pid_pat     = re.compile(r'^[a-z0-9]{32}')
        # TODO: self.base shall be automatically included in all tmpls
        self.base        = config['url_base']
        self.interval    = config.get('status_update', 2500)
        self.engine      = config.get('engine', None)
        self.check_clients = config.get('check_clients', False)
        nworkers         = config['web_workers']
        self.hot_thr     = config.get('hot_threshold', 3000)
        self.dasconfig   = dasconfig
        self.dburi       = self.dasconfig['mongodb']['dburi']
        self.lifetime    = self.dasconfig['mongodb']['lifetime']
        self.queue_limit = config.get('queue_limit', 50)
        qtype            = config.get('qtype', 'Queue')
        qfreq            = config.get('qfreq', 5)
        if  qtype not in ['Queue', 'PriorityQueue']:
            msg = 'Wrong queue type, qtype=%s' % qtype
            raise Exception(msg)
#         if  self.engine:
#             thr_name = 'DASWebService:PluginTaskManager'
#             self.taskmgr = PluginTaskManager(bus=self.engine, \
#                     nworkers=nworkers, name=thr_name, qtype=qtype, \
#                     qfreq=qfreq)
#             self.taskmgr.subscribe()
#         else:
#             thr_name = 'DASWebService:TaskManager'
#             self.taskmgr = TaskManager(nworkers=nworkers, name=thr_name, \
#                     qtype=qtype, qfreq=qfreq)
        thr_name = 'DASWebService:TaskManager'
        self.taskmgr = TaskManager(nworkers=nworkers, name=thr_name, \
                qtype=qtype, qfreq=qfreq)
        self.adjust      = config.get('adjust_input', False)
        self.dasmgr      = None # defined at run-time via self.init()
        self.reqmgr      = None # defined at run-time via self.init()
        self.daskeys     = []   # defined at run-time via self.init()
        self.colors      = {}   # defined at run-time via self.init()
        self.dbs_url     = None # defined at run-time via self.init()
        self.dbs_global  = None # defined at run-time via self.init()
        self.dbs_instances = [] # defined at run-time via self.init()
        self.kws         = None # defined at run-time via self.init()
        self.q_rewriter  = None # defined at run-time via self.init()
        self.dataset_daemon = None
        self.dbsmgr      = {} # dbs_urls vs dbs_daemons, defined at run-time
        self.daskeyslist = [] # list of DAS keys
        self.init()
        self.dbs_init(config)

        # Monitoring thread which performs auto-reconnection
        thname = 'dascore_monitor'
        start_new_thread(thname, dascore_monitor, \
                ({'das':self.dasmgr, 'uri':self.dburi}, self.init, 5))

    def dbs_init(self, config):
        """Initialize DBS daemons"""
        main_dbs_url = self.dbs_url
        dbs_urls = []
        print("### DBS URL:", self.dbs_url)
        print("### DBS global instance:", self.dbs_global)
        print("### DBS instances:", self.dbs_instances)
        for inst in self.dbs_instances:
            dbs_urls.append(\
                    (main_dbs_url.replace(self.dbs_global, inst), inst))
        interval  = config.get('dbs_daemon_interval', 3600)
        dbsexpire = config.get('dbs_daemon_expire', 3600)
        preserve_dbs_col = config.get('preserve_on_restart', False)
        dbs_config  = {'expire': dbsexpire,
                       'preserve_on_restart': preserve_dbs_col}
        for dbs_url, inst in dbs_urls:
            dbsmgr = DBSDaemon(dbs_url, self.dburi, dbs_config)
            self.dbsmgr[(dbs_url, inst)] = dbsmgr

    def init(self):
        """Init DAS web server, connect to DAS Core"""
        try:
            self.reqmgr     = RequestManager(lifetime=self.lifetime)
            self.dasmgr     = DASCore(engine=self.engine)
            self.repmgr     = CMSRepresentation(self.dasconfig, self.dasmgr)
            self.daskeys    = self.dasmgr.das_keys()
            self.gfs        = db_gridfs(self.dburi)
            self.daskeys.sort()
            self.dasmapping = self.dasmgr.mapping
            self.dbs_url    = self.dasmapping.dbs_url()
            self.dbs_global = self.dasmapping.dbs_global_instance()
            self.dbs_instances = self.dasmapping.dbs_instances()
            self.dasmapping.init_presentationcache()
            self.colors = {'das':gen_color('das')}
            for system in self.dasmgr.systems:
                self.colors[system] = gen_color(system)
            if  not self.daskeyslist:
                keylist = [r for r in self.dasmapping.das_presentation_map()]
                keylist.sort(key=lambda r: r['das'])
                self.daskeyslist = keylist

        except ConnectionFailure as _err:
            tstamp = dastimestamp('')
            mythr  = threading.current_thread()
            print("### MongoDB connection failure thread=%s, id=%s, time=%s" \
                    % (mythr.name, mythr.ident, tstamp))
        except Exception as exc:
            print_exc(exc)
            self.dasmgr  = None
            self.reqmgr  = None
            self.dbs_url = None
            self.dbs_global = None
            self.dbs_instances = []
            self.daskeys = []
            self.colors  = {}
            self.q_rewriter = None
            return

        # KWS and Query Rewriting failures are not fatal
        try:
            # init query rewriter, if needed
            if self.dasconfig['query_rewrite']['pk_rewrite_on']:
                self.q_rewriter = CMSQueryRewrite(self.repmgr,
                                                  self.templatepage)
        except Exception as exc:
            print_exc(exc)
            self.q_rewriter = None

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def redirect(self, **kwargs):
        """
        Represent DAS redirect page
        """
        dmsg = 'You do not have permission to access the resource requested.'
        msg  = kwargs.get('reason', dmsg)
        if  msg:
            msg = 'Reason: ' + msg
        page = self.templatepage('das_redirect', msg=msg)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def dumpthreads(self, **kwargs):
        """
        Represent DAS redirect page
        """
        dumpstacks('web call', 'web frame')
        msg = 'Thread dump performed: %s' % time.strftime("%Y%m%d %H:%M:%S GMT", time.gmtime())
        return self.page(msg, response_div=False)

    def bottom(self, response_div=True):
        """
        Define footer for all DAS web pages
        """
        tstamp = time.strftime("%a, %d %b %Y %H:%M:%S GMT", time.gmtime())
        return self.templatepage('das_bottom', div=response_div, base=self.base,
                version=DAS.version, time=time)

    def page(self, content, ctime=None, response_div=True):
        """
        Define footer for all DAS web pages
        """
        page  = self.top()
        page += content
        page += self.templatepage('das_bottom', ctime=ctime,  base=self.base,
                                  version=DAS.version, div=response_div, time=time)
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS + ['section', 'highlight'])
    @tools.secmodv2()
    def faq(self, **kwargs):
        """
        represent DAS FAQ.
        """
        section = kwargs.get('section', None)
        highlight = kwargs.get('highlight', None)
        guide = self.templatepage('dbsql_vs_dasql',
                    operators=', '.join(das_operators()))
        daskeys = self.templatepage('das_keys', daskeys=self.daskeyslist)
        page = self.templatepage('das_faq', guide=guide, daskeys=daskeys,
                section=section, highlight=highlight,
                operators=', '.join(das_operators()),
                aggregators=', '.join(das_aggregators()))
        return self.page(page, response_div=False)

    @expose
    @tools.secmodv2()
    def cli(self):
        """
        Serve DAS CLI file download.
        """
        msg = 'Please use dasgoclient which is available in any CMSSW releases'
        return self.page(msg)
#         dasroot = '/'.join(__file__.split('/')[:-3])
#         clifile = os.path.join(dasroot, 'DAS/tools/das_client.py')
#         return serve_file(clifile, content_type='text/plain')

    @expose
    @tools.secmodv2()
    def movetodas(self):
        "Placeholder page for DBS to DAS migration"
        style = \
            "width:600px;margin-left:auto;margin-right:auto;padding-top:20px"
        page  = """<div style="%s">""" % style
        page += "Dear user,<br/>DBS Data Discovery page is depricated.<br/>"
        page += "Please migrate to Data Aggregation Service located at"
        page += "<p>https://cmsweb.cern.ch/das/</p>"
        page += "<em>CMS HTTP group.</em>"
        page += "</div>"""
        return page

    @expose
    @tools.secmodv2()
    def opensearch(self):
        """
        Serve DAS opensearch file.
        """
        if  self.base and self.base.find('http://') != -1:
            base = self.base
        else:
            base = 'http://cmsweb.cern.ch/das'
        desc = self.templatepage('das_opensearch', base=base)
        cherrypy.response.headers['Content-Type'] = \
                'application/opensearchdescription+xml'
        return desc

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def keys(self, **kwds):
        """
        Show DAS keys and their attibutes
        """
        adict = {}
        for row in self.dasmgr.keylearning.attributes():
            try:
                qpat = row.get('query_pat', [])
                key, attr = row['member'].split('.', 1)
            except:
                continue
            if  key in adict:
                vdict = adict[key]
                if  attr in vdict:
                    vdict[attr] += qpat
                else:
                    vdict[attr] = qpat
                adict[key] = vdict
            else:
                adict[key] = {attr: qpat}
        view = kwds.get('view', '')
        if  view == 'json':
            return json.dumps(adict)
        page = self.templatepage('das_keys_attrs', attrs=adict)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def services(self):
        """
        represent DAS services
        """
        dasdict = {}
        daskeys = set()
        dasmapkeys = list(self.dasmgr.mapping.dasmapscache.keys())
        dasmapkeys.sort()
        for key in dasmapkeys:
            srv, urn = key
            if  srv not in self.dasmgr.systems:
                continue
            entry = self.dasmgr.mapping.dasmapscache[key]
            tmpdict = {}
            for item in entry['das_map']:
                dkey = item['das_key']
                rkey = item['rec_key']
                daskeys.add(dkey)
                vlist = tmpdict.get(dkey, []) + [rkey]
                tmpdict[dkey] = list(set(vlist))
            apis = []
            if  srv in dasdict:
                vdict = dasdict[srv]
                okeys = vdict['keys']
                apis  = vdict['apis'] + [urn]
                for kkk, vvv in okeys.items():
                    vlist = tmpdict.get(kkk, []) + vvv
                    tmpdict[kkk] = list(set(vlist))
            else:
                apis = [urn]
            vdict = dict(keys=dict(tmpdict), apis=apis)
            dasdict[srv] = vdict
        mapreduce = [r for r in self.dasmgr.rawcache.get_map_reduce()]
        page = self.templatepage('das_services', dasdict=dasdict,
                        dbses=self.dbs_instances, dbs_global=self.dbs_global,
                        daskeys=list(daskeys), mapreduce=mapreduce,
                        urllib=urllib)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def nsystems(self):
        """
        Return number of systems participating in DAS
        """
        systems = self.dasmgr.mapping.list_systems()
        return "DAS systems %s" % ','.join(systems)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def api(self, system, name):
        """
        Return DAS mapping record about provided API.
        """
        record = self.dasmgr.mapping.api_info(system, name)
        page   = "<b>DAS mapping record</b>"
        page  += das_json_full(record)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def default(self, *args, **kwargs):
        """
        Default method.
        """
        return self.index(args, kwargs)

    def adjust_input(self, kwargs):
        """
        Adjust user input wrt common DAS keyword patterns, e.g.
        /Zee/*/* -> dataset=*Zee*, T1_US -> site=T1_US.

        More ambiguous input (such as Zee -> dataset=*Zee*) is however left
        to be handled by the keyword search.

        This is active only if adjust_input is set in DAS server configuration.
        """
        if not self.adjust:
            return
        uinput = kwargs.get('input', '')
        inst = kwargs.get('instance', self.dbs_global)

        kwargs['input'] = identify_apparent_query_patterns(uinput, inst)

    def _get_dbsmgr(self, inst):
        """
        Given a string representation of DBS instance, returns DBSManager
        instance which "knows" how to look up datasets
        """
        mgr = None
        # instance selection shall be more clean
        if not self.dataset_daemon:
            return mgr
        for dbs_url, dbs_inst in self.dbsmgr.keys():
            if  dbs_inst == inst:
                return self.dbsmgr[(dbs_url, dbs_inst)]
        return mgr


    def _get_kws_host(self):
        """
        gets the host for keyword search from config. default is same server
        """
        return self.dasconfig['load_balance']['kws_host']

    def _get_autocompl_host(self):
        """
        gets the host for autocompletion from config. default is same server
        """
        conf = self.dasconfig.get('load_balance', {})
        return conf.get('autocompletion_host', '')

    def is_kws_enabled(self):
        """
        is keyword search client (ajax request) enabled
        """
        return self.dasconfig['keyword_search']['kws_on']

    def is_kws_service_enabled(self):
        """
        is keyword search service (response to ajax call) enabled
        """
        return self.dasconfig['keyword_search']['kws_service_on']

    def generate_dasquery(self, uinput, inst, html_mode=True, qcache=0):
        """
        Check provided input as valid DAS input query.
        Returns status and content (either error message or valid DASQuery)
        :param uinput: user's input
        :param inst: DBS instance
        :param html_mode: whether errors shall be output in html
        """

        def error_msg(msg, show_kws=False, tmpl='das_ambiguous', **kwargs):
            """
            Helper function which renders an error template, default is
            das_ambiguous, but can be overriden via tmpl param.
            Template has two versions: html and text for CLI.

            The template is passed with msg, base, guide, and **kwargs. """
            # TODO: this shall be done by inheriting a parent template
            # TODO: no header/footer?
            guide = self.templatepage('dbsql_vs_dasql',
                                      operators=', '.join(das_operators()))
            # render keyword search loader, if needed
            kws = ''
            if show_kws:
                kws = self.templatepage('kwdsearch_via_ajax',
                                        uinput=uinput,
                                        jsonize=jsonize,
                                        url_extend_params_as_dict=url_extend_params_as_dict,
                                        inst=inst or self.dbs_global,
                                        kws_host=self._get_kws_host())
            # render the appropriate template (html vs text mode)
            page = self.templatepage(tmpl + ('_txt' if not html_mode else ''),
                                     msg=msg, base=self.base, guide=guide,
                                     kws_enabled=show_kws, kws=kws, **kwargs)
            return page

        if not uinput:
            return 1, error_msg('No input query')

        # Generate a DASQuery object, if it fails we catch the exception and
        # wrap it for upper layer (web interface)
        try:
            dasquery = DASQuery(uinput, instance=inst, qcache=qcache)
        except WildcardMultipleMatchesException as err:
            # TODO: hints could be shown here also, but it makes no sense, as
            # they are shown only when no matches are found
            if isinstance(err.options.values, list) and err.options.values:
                return 1, error_msg(str(err), tmpl='das_wildcard_err',
                                    suggest=err.options.values,
                                    url_extend_params=url_extend_params)
            return 1, error_msg(str(err), tmpl='das_wildcard_err',
                                url_extend_params=url_extend_params)

        except WildcardMatchingException as err:
            kwds = {'input':uinput, 'instance':inst}
            hints = self.hint_datasets(kwds)
            page = error_msg(str(err))
            for hint in hints:
                page += self.templatepage('hint',
                        url_extend_params=url_extend_params,
                        hint=hint, base=self.base, dbs=self.dbs_global)
            return 1, page
        except Exception as err:
            # show multiple dataset matches for 1 keyword queries
            if hasattr(response, 'dataset_matches_msg'):
                return 1, error_msg(response.dataset_matches_msg,
                                    show_kws=self.is_kws_enabled())

            # for non Wildcard parsing errors, show the Keyword Search
            return 1, error_msg(str(err), show_kws=self.is_kws_enabled())

        if dasquery.error:
            return 1, error_msg(dasquery.error)

        # DAS query validation
        if isinstance(uinput, dict):  # DASQuery w/ {'spec':{'_id:id}}
            pass
        elif uinput.find('queries') != -1:
            pass
        elif uinput.find('records') != -1:
            pass
        else:  # normal user DAS query
            try:
                service_map = dasquery.service_apis_map()
            except Exception as exc:
                msg = 'Fail to obtain service API map for this DASQuery'
                print(msg)
                print_exc(exc)
                return 1, error_msg(msg)
            if not service_map:
                return 1, error_msg('Unable to resolve the query over the '
                                    'available services: %s' % dasquery)
        return 0, dasquery

    @expose
    @checkargs(DAS_WEB_INPUTS)
#    @tools.secmodv2()
    def index(self, *args, **kwargs):
        """
        represents DAS web interface.
        It uses das_searchform template for
        input form and yui_table for output Table widget.
        """
        uinput = getarg(kwargs, 'input', '')
        return self.page(self.form(uinput=uinput, cards=True))


    def form(self, uinput='', instance=None, view='list', cards=False):
        """
        provide input DAS search form
        """
        # TODO: rename into search_form()? (template is also called like this

        if  "'" in uinput: # e.g. file.creation_date>'20120101 12:01:01'
            uinput = uinput.replace("'", '"')
        if  not instance:
            instance = self.dbs_global
        hcards = help_cards(self.base)
        width = 900
        height = 220
        cards = self.templatepage('das_cards', base=self.base, show=cards, \
                width=width, height=height, max_width=len(hcards)*width, \
                cards=hcards, enumerate=enumerate)
        daskeys = self.templatepage('das_keys', daskeys=self.daskeyslist)
        page  = self.templatepage('das_searchform', input=uinput, \
                init_dbses=list(self.dbs_instances), daskeys=daskeys, \
                base=self.base, instance=instance, view=view, cards=cards,
                autocompl_host=json.dumps(self._get_autocompl_host())
                )
        return page

    @expose
    @tools.secmodv2()
    def error(self, msg, wrap=True):
        """
        Show error message.
        """
        page = self.templatepage('das_error', msg=str(msg))
        if  wrap:
            page  = self.page(self.form() + page)
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def gridfs(self, **kwargs):
        """
        Retieve records from GridFS
        """
        time0 = time.time()
        if  'fid' not in kwargs:
            code = web_code('No file id')
            raise HTTPError(500, 'DAS error, code=%s' % code)
        fid  = kwargs.get('fid')
        data = {'status':'requested', 'fid':fid}
        try:
            fds = self.gfs.get(ObjectId(fid))
            return fds.read()
        except Exception as exc:
            print_exc(exc)
            code = web_code('Exception')
            raise HTTPError(500, 'DAS error, code=%s' % code)
        data['ctime'] = time.time() - time0
        return json.dumps(data)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def records(self, *args, **kwargs):
        """
        Retieve all records id's.
        """
        try:
            recordid = None
            if  args:
                recordid = args[0]
                spec = {'_id':ObjectId(recordid)}
                fields = None
                query = dict(fields=fields, spec=spec)
            elif  kwargs and '_id' in kwargs:
                spec = {'_id': ObjectId(kwargs['_id'])}
                fields = None
                query = dict(fields=fields, spec=spec)
            else: # return all ids
                query = dict(fields=None, spec={})

            res      = ''
            time0    = time.time()
            idx      = getarg(kwargs, 'idx', 0)
            limit    = getarg(kwargs, 'limit', 50)
            coll     = kwargs.get('collection', 'merge')
            view     = kwargs.get('view', '')
            if  view == 'json':
                res  = []
            inst     = kwargs.get('instance', self.dbs_global)
            form     = self.form(uinput="")
            check, content = self.generate_dasquery(query, inst)
            if  check:
                return self.page(form + content, ctime=time.time()-time0)
            dasquery = content # returned content is valid DAS query
            nresults = self.dasmgr.rawcache.nresults(dasquery, coll)
            gen      = self.dasmgr.rawcache.get_from_cache\
                (dasquery, idx=idx, limit=limit, collection=coll)
            if  recordid: # we got id
                for row in gen:
                    if  view == 'json':
                        res.append(row)
                    else:
                        res += das_json(dasquery, row)
            else:
                for row in gen:
                    rid  = row['_id']
                    del row['_id']
                    res += self.templatepage('das_record', \
                            id=rid, collection=coll, daskeys=', '.join(row))
            if  recordid:
                page  = res
            else:
                url   = '/das/records?'
                if  nresults:
                    page = self.templatepage('das_pagination', \
                        nrows=nresults, idx=idx, limit=limit, url=url, \
                        cgi=cgi, str=str)
                else:
                    page = 'No results found, nresults=%s' % nresults
                page += res

            ctime   = (time.time()-time0)
            if  view == 'json':
                return json.dumps(res)
            page = self.page(form + page, ctime=ctime)
            return page
        except Exception as exc:
            print_exc(exc)
            return self.error(gen_error_msg(kwargs))

    @jsonstreamer
    def datastream(self, kwargs):
        """Stream DAS data into JSON format"""
        head = kwargs.get('head', dict(timestamp=time.time()))
        if  'mongo_query' not in head:
            head['mongo_query'] = head['dasquery'].mongo_query \
                if 'dasquery' in head else {}
        if  'dasquery' in head:
            del head['dasquery']
        if  'args' in head:
            del head['args']
        data = kwargs.get('data', [])
        if  self.check_clients:
            # update client version
            cli, cli_msg = check_client_version()
            head.update({'client': cli, 'client_message': cli_msg})
        return head, data

    def hint_datasets(self, kwargs):
        "Use hint functions to find datasets in non-default DBS istances"
        query = kwargs.get('input', '').strip()
        dbsinst = kwargs.get('instance', self.dbs_global)
        hint_functions = [hint_dataset_case_insensitive,
                          hint_dataset_in_other_insts, ]
        hints = (hint(query, dbsinst) for hint in hint_functions)
        hints = [r for r in hints if r and r.get('results')]
        return hints

    def get_data(self, kwargs):
        """
        Invoke DAS workflow and get data from the cache.
        """
        head   = dict(timestamp=time.time())
        head['args'] = kwargs
        uinput = kwargs.get('input', '')
        inst   = kwargs.get('instance', self.dbs_global)
        idx    = getarg(kwargs, 'idx', 0)
        limit  = getarg(kwargs, 'limit', 0) # do not impose limit
        coll   = kwargs.get('collection', 'merge')
        status = kwargs.get('status')
        error  = kwargs.get('error')
        reason = kwargs.get('reason')
        dasquery = kwargs.get('dasquery', None)
        time0  = time.time()
        if  dasquery:
            dasquery = DASQuery(dasquery, instance=inst)
            if  dasquery.error:
                return self.page(form + dasquery.error, ctime=time.time()-time0)
        else:
            check, content = \
                    self.generate_dasquery(uinput, inst, html_mode=False)
            if  check:
                head.update({'status': 'fail', 'reason': content,
                             'ctime': time.time()-time0, 'input': uinput})
                data = []
                return head, data
            dasquery = content # returned content is valid DAS query
        try:
            nres = self.dasmgr.nresults(dasquery, coll)
            data = \
                self.dasmgr.get_from_cache(dasquery, idx, limit)
            # check that we got what we expected
            data = [r for r in data]
            if  nres and not len(data):
                for retry in range(1, 3, 5):
                    msg = 'retry in %s sec' % retry
                    dasprint(dastimestamp('DAS WARNING '), msg, dasquery)
                    time.sleep(retry) # retry one more time
                    data = \
                        self.dasmgr.get_from_cache(dasquery, idx, limit)
                    data = [r for r in data]
                    if  len(data):
                        break
            if  nres and not len(data):
                msg = 'fail to get all data for %s, nres=%s, len(data)=%s' \
                        % (dasquery, nres, len(data))
                dasprint(dastimestamp('DAS WARNING '), msg)
                status = 'fail'
                reason = 'Fail to retrieve data from DAS cache, please retry'

            if  dasquery.aggregators:
                # aggregators split DAS record into sub-system and then
                # apply aggregator functions, therefore we need to correctly
                # account for nresults. Resolve generator into list and take
                # its length as nresults value.
                data = [r for r in data]
                nres = len(data)
            if  error: # DAS record contains an error
                status = 'error'
            head.update({'status':status, 'nresults':nres,
                         'ctime': time.time()-time0, 'dasquery': dasquery})
        except Exception as exc:
            status = 'fail'
            reason = str(exc)
            print_exc(exc)
            head.update({'status': status,
                         'ctime': time.time()-time0, 'dasquery': dasquery})
            data = []
        head.update({'incache':self.dasmgr.incache(dasquery, coll='cache'),
                     'apilist':self.dasmgr.apilist(dasquery)})
        if  reason:
            head.update({'reason': reason})
        if  status != 'ok':
            head.update(self.info())

        # check if query had dataset input and returned no results
        # then run hint functions to find dataset in other DBS instances
        mquery = dasquery.mongo_query
        empty = False
        for item in data:
            if  'dataset.name' in mquery['spec'] and 'dataset' in mquery['fields'] \
                    and 'result' not in item:
                if  not item['dataset']:
                    empty = True
                    break
        if  empty: # if no results found add dataset from other DBS instances
            hints = self.hint_datasets(kwargs)
            for item in data:
                item.update({'hints': hints})

        return head, data

    def info(self):
        "Return status of DAS server"
        info = {'nrequests': self.reqmgr.size(),
                'nworkers': self.taskmgr.nworkers(),
                'dasweb': self.reqmgr.status()}
        if  self.dasmgr and self.dasmgr.taskmgr:
            info.update({'dascore': self.dasmgr.taskmgr.status()})
        return dict(das_server=info)

    def busy(self):
        """
        Check server load and report busy status if
        nrequests - nworkers > queue limit
        """
        nrequests = self.reqmgr.size()
        if  (nrequests - self.taskmgr.nworkers()) > self.queue_limit:
            msg = '#request=%s, queue_limit=%s, #workers=%s' \
                    % (nrequests, self.taskmgr.nworkers(), self.queue_limit)
            dasprint(dastimestamp('DAS WEB SERVER IS BUSY '), msg)
            return True
        return False

    def busy_page(self, uinput=None):
        """DAS server busy page layout"""
        page = "<h3>DAS server is busy, please try later</h3>"
        form = self.form(uinput)
        return self.page(form + page)

    def _is_web_request(self, view):
        """
        returns whether the current view mode is not web
        """

        # first, check for explicit output type (view)

        if view in ['json', 'xml', 'plain']:
            return False

        # check accept header - e.g. das client only provides accept header
        accepts = cherrypy.request.headers.elements('Accept')
        non_html_accepts = ['application/json']
        other_accepted = [a for a in accepts
                          if a.value not in non_html_accepts]

        # if only non html content types are accepted we are in non html mode
        if not other_accepted and accepts:
            return  False

        return True

    def empty_return(self, dasquery, status='busy', reason=None):
        "Return header/data when DAS server is busy"
        if  not reason:
            reason  = 'DAS server is busy'
            reason += ', #requests=%s, #workers=%s, queue size=%s' \
                % (self.reqmgr.size(), self.taskmgr.nworkers(), self.queue_limit)
        head = dict(timestamp=time.time())
        head.update({'status': status, 'reason': reason, 'ctime':0})
        data = []
        dasprint(dastimestamp('DAS INFO '), dasquery, 'server status=%s'%status, reason)
        return self.datastream(dict(head=head, data=data))

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def cache(self, **kwargs):
        """
        DAS web cache interface. Fire up new process for new requests and
        record its pid. The client is in charge to keep track of pid.
        The new process uses DAS core call to request the data into cache.
        Since query are cached the repeated call with the same query
        has no cost to DAS core.
        """
        # do not allow caching
        set_no_cache_flags()

        # if busy return right away
        if  self.busy():
            return self.empty_return(kwargs)

        uinput = kwargs.get('input', '').strip()
        check_query(uinput)
        if  not uinput:
            head = {'status': 'fail', 'reason': 'No input found',
                    'args': kwargs, 'ctime': 0, 'input': uinput}
            data = []
            return self.datastream(dict(head=head, data=data))
        self.adjust_input(kwargs)
        pid    = kwargs.get('pid', '')
        inst   = kwargs.get('instance', self.dbs_global)
        uinput = kwargs.get('input', '')
        view   = kwargs.get('view', 'list')
        qcache = kwargs.get('qcache', 0)
        data   = []

        # textual views need text only error messages...
        check, content = self.generate_dasquery(uinput, inst,
                              html_mode=self._is_web_request(view),
                              qcache=qcache)
        if  check:
            head = dict(timestamp=time.time())
            head.update({'status': 'fail',
                         'reason': 'Can not interpret the query'+ \
                                   ' (while creating DASQuery)',
                         'ctime': 0})
            if not self._is_web_request(view):
                head['error_details'] = content
                head['reason'] = head['reason'] + '\n\n' + content
            return self.datastream(dict(head=head, data=data))

        dasquery = content # returned content is valid DAS query
        status, error, reason = self.dasmgr.get_status(dasquery)
        kwargs.update({'status':status, 'error':error, 'reason':reason})
        if  not pid:
            pid = dasquery.qhash
        if  status == None and not self.reqmgr.has_pid(pid): # submit new request
            uid = cherrypy.request.headers.get('Remote-Addr')
            if  hasattr(cherrypy.request, 'user'):
                uid = cherrypy.request.user.get('dn', None)
            _evt, pid = self.taskmgr.spawn(\
                self.dasmgr.call, dasquery, uid=uid, pid=dasquery.qhash)
            self.reqmgr.add(pid, kwargs)
            return pid
        if  status == 'ok':
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)
            kwargs['dasquery'] = dasquery
            head, data = self.get_data(kwargs)
            return self.datastream(dict(head=head, data=data))
        kwargs['dasquery'] = dasquery.storage_query
        if  not self.pid_pat.match(str(pid)) or len(str(pid)) != 32:
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)
            return self.empty_return(dasquery, 'fail', 'Invalid pid')
        elif self.taskmgr.is_alive(pid):
            return pid
        elif status == None:
            # DAS was busy and query expired since status==None
            if  not self.taskmgr.is_alive(pid) and self.reqmgr.has_pid(pid):
                self.reqmgr.remove(pid)
                self.taskmgr.remove(pid)
                return self.empty_return(dasquery, 'fail', 'request expired')
            return pid
        else: # process is done, get data
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)
            head, data = self.get_data(kwargs)
            return self.datastream(dict(head=head, data=data))

    def get_page_content(self, kwargs, complete_msg=True):
        """Retrieve page content for provided set of parameters"""
        html_views = ['list', 'table']
        page = ''
        try:
            view = kwargs.get('view', 'list')
            if  view == 'plain':
                if  'limit' in kwargs:
                    del kwargs['limit']
            if  view in ['json', 'xml', 'plain'] and complete_msg:
                page = 'Request completed. Reload the page ...'
            else:
                head, data = self.get_data(kwargs)

                allowed_views = ['list', 'table', 'plain', 'xml', 'json']
                if view not in allowed_views:
                    raise

                func = getattr(self, view + "view")
                page = func(head, data)
        except HTTPError as _err:
            raise
        except Exception as exc:
            print_exc(exc)
            msg  = gen_error_msg(kwargs)
            page = self.templatepage('das_error', msg=msg)
        return page

    @expose
    @tools.secmodv2()
    def download(self, lfn):
        "DAS download page for given LFN"
        page = self.templatepage('filemover', lfn=lfn)
        return self.page(page, response_div=False)

    @expose
    @tools.secmodv2()
    def makepy(self, dataset, instance):
        """
        Request to create CMSSW py snippet for a given dataset
        """
        pat = re.compile('/.*/.*/.*')
        if  not pat.match(dataset):
            msg = 'Invalid dataset name'
            return self.error(msg)
        query = "file dataset=%s instance=%s | grep file.name" \
                % (dataset, instance)
        try:
            data   = self.dasmgr.result(query, idx=0, limit=0)
        except Exception as exc:
            print_exc(exc)
            msg    = 'Exception: %s\n' % str(exc)
            msg   += 'Unable to retrieve data for query=%s' % query
            return self.error(msg)
        lfns = []
        for rec in data:
            filename = DotDict(rec).get('file.name')
            if  filename not in lfns:
                lfns.append(filename)
        page = self.templatepage('das_files_py', lfnList=lfns, pfnList=[], isinstance=isinstance, list=list)
        cherrypy.response.headers['Content-Type'] = "text/plain"
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS)
    @tools.secmodv2()
    def request(self, **kwargs):
        """
        Request data from DAS cache.
        """
        # do not allow caching
        set_no_cache_flags()

        uinput  = kwargs.get('input', '').strip()
        check_query(uinput)
        if  not uinput:
            kwargs['reason'] = 'No input found'
            return self.redirect(**kwargs)

        # if busy return right away
        if  self.busy():
            return self.busy_page(uinput)

        time0   = time.time()
        self.adjust_input(kwargs)
        view    = kwargs.get('view', 'list')
        qcache  = kwargs.get('qcache', 0)
        if  'instance' in uinput:
            form     = self.form(uinput=uinput, view=view)
            content  = 'On DAS web UI please use drop-down menu to specify DBS'
            content += ' instance to avoid ambiguity. '
            content += 'To proceed please clear your input query.'
            return self.page(form + '<div class="box_red">%s</div>' % content)
        else:
            inst = kwargs.get('instance', self.dbs_global)
        uinput  = kwargs.get('input', '')
        form    = self.form(uinput=uinput, instance=inst, view=view)
        check, content = self.generate_dasquery(uinput, inst, qcache=qcache)
        if  check:
            if  view == 'list' or view == 'table':
                return self.page(form + content, ctime=time.time()-time0)
            else:
                return content
        dasquery = content # returned content is valid DAS query
        status, error, reason = self.dasmgr.get_status(dasquery)
        kwargs.update({'status':status, 'error':error, 'reason':reason})
        pid = dasquery.qhash
        if  status is None: # process new request
            kwargs['dasquery'] = dasquery.storage_query
            uid = cherrypy.request.headers.get('Remote-Addr')
            if  hasattr(cherrypy.request, 'user'):
                uid = cherrypy.request.user.get('dn', None)
            _evt, pid = self.taskmgr.spawn(self.dasmgr.call, dasquery,
                    uid=uid, pid=dasquery.qhash)
            self.reqmgr.add(pid, kwargs)
        elif status == 'ok' or status == 'fail':
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)

            # check if query can be rewritten via nested PK query
            rew_msg = self.q_rewriter and self.q_rewriter.check_fields(dasquery)
            if rew_msg:
                content =  self.templatepage('das_error', msg=rew_msg)
                return self.page(form + content, ctime=time.time()-time0)

            kwargs['dasquery'] = dasquery
            page = self.get_page_content(kwargs, complete_msg=False)
            ctime = (time.time()-time0)
            if  view == 'list' or view == 'table':
                return self.page(form + page, ctime=ctime)

            return page
        if  self.taskmgr.is_alive(pid):
            page = self.templatepage('das_check_pid', method='check_pid',
                    uinput=uinput, view=view, urllib=urllib,
                    base=self.base, pid=pid, interval=self.interval)
        elif status == None:
            # DAS was busy and query expired since status==None
            if  not self.taskmgr.is_alive(pid) and self.reqmgr.has_pid(pid):
                self.reqmgr.remove(pid)
                self.taskmgr.remove(pid)
                return self.empty_return(dasquery, 'fail', 'request expired')
            page = self.templatepage('das_check_pid', method='check_pid',
                    uinput=uinput, view=view, urllib=urllib,
                    base=self.base, pid=pid, interval=self.interval)
        else:
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)
            page = self.get_page_content(kwargs)
        ctime = (time.time()-time0)
        return self.page(form + page, ctime=ctime)

    @expose
    @tools.secmodv2()
    def status(self):
        """Return list of all current requests in DAS queue"""
        requests = [r for r in self.reqmgr.items()]
        page = self.templatepage('das_status', requests=requests, time=time)

        sdict = self.dasmgr.status()
        sdict['web'] = self.taskmgr.status()
        dasprint(dastimestamp('DAS INFO '), "web TaskManager", sdict['web'])
        for key, val in sdict.items():
            dasprint(dastimestamp('DAS INFO '), "%s TaskManager %s" % (key, val))
        page += '<h3>Services</h3>'
        def dump(idict):
            "Dump input dict"
            return ', '.join(['<em>%s:</em> %s' % (k, idict[k]) for k in sorted(idict)])
        for key, val in sdict.items():
            page += '<div>'
            stats = ', '.join([dump(v) for v in val.values()])
            page += '<b>%s</b>: %s' % (key, stats)
            page += '</div>'
        return self.page(page)

    @expose
    @checkargs(['pid'])
    @tools.secmodv2()
    def check_pid(self, pid):
        """
        Check status of given pid. This is a server callback
        function for ajaxCheckPid, see js/ajax_utils.js
        """
        # do not allow caching
        set_no_cache_flags()

        img  = '<img src="%s/images/loading.gif" alt="loading"/>' % self.base
        page = ''
        try:
            if  self.taskmgr.is_alive(pid):
                page = img + " processing PID=%s" % pid
            else:
                # at this point we don't know if request arrived to this host
                # or it was processed. To distinguish the case we'll ask
                # request manager for that pid
                if  self.reqmgr.has_pid(pid):
                    self.reqmgr.remove(pid)
                    self.taskmgr.remove(pid)
                    page  = 'Request PID=%s is completed' % pid
                    page += ', please wait for results to load'
                else:
                    # there're no request on this server, re-initiate it
                    ref = cherrypy.request.headers.get('Referer', None)
                    if  ref:
                        url = urlparse(ref)
                        params = dict(parse_qsl(url.query))
                        return self.request(**params)
                    else:
                        msg  = 'No referer in cherrypy.request.headers'
                        msg += '\nHeaders: %s' % cherrypy.request.headers
                        dasprint(dastimestamp('DAS WEB ERROR '), msg)
        except Exception as err:
            msg = 'check_pid fails for pid=%s' % pid
            dasprint(dastimestamp('DAS WEB ERROR '), msg)
            print_exc(err)
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)
            return self.error(gen_error_msg({'pid':pid}), wrap=False)
        return page

    def listview(self, head, data):
        """DAS listview data representation"""
        return self.repmgr.listview(head, data)

    def tableview(self, head, data):
        """DAS tabular view data representation"""
        return self.repmgr.tableview(head, data)

    def plainview(self, head, data):
        """DAS plain view data representation"""
        return self.repmgr.plainview(head, data)

    def xmlview(self, head, data):
        """DAS XML data representation"""
        return self.repmgr.xmlview(head, data)

    def jsonview(self, head, data):
        """DAS JSON data representation"""
        return self.repmgr.jsonview(head, data)

    @exposedasjson
    @enable_cross_origin
    @checkargs(['query', 'dbs_instance'])
    @tools.secmodv2()
    def autocomplete(self, **kwargs):
        """
        Provides autocomplete functionality for DAS web UI.
        """
        query = kwargs.get("query", "").strip()
        result = autocomplete_helper(query, self.dasmgr, self.daskeys)
        dataset = [r for r in result if r['value'].find('dataset=')!=-1]
        dbsinst = kwargs.get('dbs_instance', self.dbs_global)
        if  self.dataset_daemon and len(dataset):
            dbsmgr = self._get_dbsmgr(dbsinst)
            # we shall autocomplete the last token so queries like
            # file dataset=/ZMM/.. are autocompleted
            prefix = ''
            if ' ' in query:
                prefix = '  '.join(query.split()[:-1]) + ' '
                print('prefix=', prefix)
                query = query.split()[-1]
            if  query.find('dataset=') != -1:
                query = query.replace('dataset=', '')
            for row in dbsmgr.find(query):
                result.append({'css': 'ac-info',
                               'value': prefix + 'dataset=%s' % row,
                               'info': 'dataset'})
        return result
Example #7
0
class DASWebService(DASWebManager):
    """
    DAS web service interface.
    """

    def __init__(self, dasconfig):
        DASWebManager.__init__(self, dasconfig)
        config = dasconfig["web_server"]
        self.pid_pat = re.compile(r"^[a-z0-9]{32}")
        self.base = config["url_base"]
        self.interval = config.get("status_update", 2500)
        self.engine = config.get("engine", None)
        self.check_clients = config.get("check_clients", False)
        nworkers = config["web_workers"]
        self.hot_thr = config.get("hot_threshold", 3000)
        self.dasconfig = dasconfig
        self.dburi = self.dasconfig["mongodb"]["dburi"]
        self.lifetime = self.dasconfig["mongodb"]["lifetime"]
        self.queue_limit = config.get("queue_limit", 50)
        qtype = config.get("qtype", "Queue")
        if qtype not in ["Queue", "PriorityQueue"]:
            msg = "Wrong queue type, qtype=%s" % qtype
            raise Exception(msg)
        if self.engine:
            thr_name = "DASWebService:PluginTaskManager"
            self.taskmgr = PluginTaskManager(bus=self.engine, nworkers=nworkers, name=thr_name, qtype=qtype)
            self.taskmgr.subscribe()
        else:
            thr_name = "DASWebService:TaskManager"
            self.taskmgr = TaskManager(nworkers=nworkers, name=thr_name, qtype=qtype)
        self.adjust = config.get("adjust_input", False)
        self.dasmgr = None  # defined at run-time via self.init()
        self.reqmgr = None  # defined at run-time via self.init()
        self.daskeys = []  # defined at run-time via self.init()
        self.colors = {}  # defined at run-time via self.init()
        self.dbs_url = None  # defined at run-time via self.init()
        self.dbs_global = None  # defined at run-time via self.init()
        self.kws = None  # defined at run-time via self.init()
        self.q_rewriter = None  # defined at run-time via self.init()
        self.dataset_daemon = config.get("dbs_daemon", False)
        self.dbsmgr = {}  # dbs_urls vs dbs_daemons, defined at run-time
        self.daskeyslist = []  # list of DAS keys
        self.init()

        # Monitoring thread which performs auto-reconnection
        thname = "dascore_monitor"
        start_new_thread(thname, dascore_monitor, ({"das": self.dasmgr, "uri": self.dburi}, self.init, 5))

    def dbs_daemon(self, config):
        """Start DBS daemon if it is requested via DAS configuration"""
        try:
            main_dbs_url = self.dbs_url
            dbs_urls = []
            print "### DBS URL:", self.dbs_url
            print "### DBS instances:", self.dbs_instances
            if not self.dbs_url or not self.dbs_instances:
                return  # just quit
            for inst in self.dbs_instances:
                dbs_urls.append((main_dbs_url.replace(self.dbs_global, inst), inst))
            interval = config.get("dbs_daemon_interval", 3600)
            dbsexpire = config.get("dbs_daemon_expire", 3600)
            preserve_dbs_col = config.get("preserve_on_restart", False)
            dbs_config = {"expire": dbsexpire, "preserve_on_restart": preserve_dbs_col}
            if self.dataset_daemon:
                for dbs_url, inst in dbs_urls:
                    dbsmgr = DBSDaemon(dbs_url, self.dburi, dbs_config)
                    self.dbsmgr[(dbs_url, inst)] = dbsmgr

                    def dbs_updater(_dbsmgr, interval):
                        """DBS updater daemon"""
                        while True:
                            try:
                                _dbsmgr.update()
                            except:
                                pass
                            time.sleep(interval)

                    print "### Start DBSDaemon for %s" % dbs_url
                    thname = "dbs_updater:%s" % dbs_url
                    start_new_thread(thname, dbs_updater, (dbsmgr, interval))
        except Exception as exc:
            print_exc(exc)

    def init(self):
        """Init DAS web server, connect to DAS Core"""
        try:
            self.reqmgr = RequestManager(lifetime=self.lifetime)
            self.dasmgr = DASCore(engine=self.engine)
            self.repmgr = CMSRepresentation(self.dasconfig, self.dasmgr)
            self.daskeys = self.dasmgr.das_keys()
            self.gfs = db_gridfs(self.dburi)
            self.daskeys.sort()
            self.dasmapping = self.dasmgr.mapping
            self.dbs_url = self.dasmapping.dbs_url()
            self.dbs_global = self.dasmapping.dbs_global_instance()
            self.dbs_instances = self.dasmapping.dbs_instances()
            self.dasmapping.init_presentationcache()
            self.colors = {"das": gen_color("das")}
            for system in self.dasmgr.systems:
                self.colors[system] = gen_color(system)
            # get SiteDB from global scope
            self.sitedbmgr = SERVICES.get("sitedb2", None)
            # Start DBS daemon
            if self.dataset_daemon:
                self.dbs_daemon(self.dasconfig["web_server"])
            if not self.daskeyslist:
                keylist = [r for r in self.dasmapping.das_presentation_map()]
                keylist.sort(key=lambda r: r["das"])
                self.daskeyslist = keylist

        except ConnectionFailure as _err:
            tstamp = dastimestamp("")
            mythr = threading.current_thread()
            print "### MongoDB connection failure thread=%s, id=%s, time=%s" % (mythr.name, mythr.ident, tstamp)
        except Exception as exc:
            print_exc(exc)
            self.dasmgr = None
            self.reqmgr = None
            self.dbs_url = None
            self.dbs_global = None
            self.dbs_instances = []
            self.daskeys = []
            self.colors = {}
            self.q_rewriter = None
            return

        # KWS and Query Rewriting failures are not fatal
        try:
            # init query rewriter, if needed
            if self.dasconfig["query_rewrite"]["pk_rewrite_on"]:
                self.q_rewriter = CMSQueryRewrite(self.repmgr, self.templatepage)
        except Exception as exc:
            print_exc(exc)
            self.q_rewriter = None

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def redirect(self, **kwargs):
        """
        Represent DAS redirect page
        """
        dmsg = "You do not have permission to access the resource requested."
        msg = kwargs.get("reason", dmsg)
        if msg:
            msg = "Reason: " + msg
        page = self.templatepage("das_redirect", msg=msg)
        return self.page(page, response_div=False)

    def bottom(self, response_div=True):
        """
        Define footer for all DAS web pages
        """
        return self.templatepage("das_bottom", div=response_div, base=self.base, version=DAS.version)

    def page(self, content, ctime=None, response_div=True):
        """
        Define footer for all DAS web pages
        """
        page = self.top()
        page += content
        page += self.templatepage("das_bottom", ctime=ctime, base=self.base, version=DAS.version, div=response_div)
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS + ["section", "highlight"])
    def faq(self, **kwargs):
        """
        represent DAS FAQ.
        """
        section = kwargs.get("section", None)
        highlight = kwargs.get("highlight", None)
        guide = self.templatepage("dbsql_vs_dasql", operators=", ".join(das_operators()))
        daskeys = self.templatepage("das_keys", daskeys=self.daskeyslist)
        page = self.templatepage(
            "das_faq",
            guide=guide,
            daskeys=daskeys,
            section=section,
            highlight=highlight,
            operators=", ".join(das_operators()),
            aggregators=", ".join(das_aggregators()),
        )
        return self.page(page, response_div=False)

    @expose
    def cli(self):
        """
        Serve DAS CLI file download.
        """
        dasroot = "/".join(__file__.split("/")[:-3])
        clifile = os.path.join(dasroot, "DAS/tools/das_client.py")
        return serve_file(clifile, content_type="text/plain")

    @expose
    def movetodas(self):
        "Placeholder page for DBS to DAS migration"
        style = "width:600px;margin-left:auto;margin-right:auto;padding-top:20px"
        page = """<div style="%s">""" % style
        page += "Dear user,<br/>DBS Data Discovery page is depricated.<br/>"
        page += "Please migrate to Data Aggregation Service located at"
        page += "<p>https://cmsweb.cern.ch/das/</p>"
        page += "<em>CMS HTTP group.</em>"
        page += "</div>" ""
        return page

    @expose
    def opensearch(self):
        """
        Serve DAS opensearch file.
        """
        if self.base and self.base.find("http://") != -1:
            base = self.base
        else:
            base = "http://cmsweb.cern.ch/das"
        desc = self.templatepage("das_opensearch", base=base)
        cherrypy.response.headers["Content-Type"] = "application/opensearchdescription+xml"
        return desc

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def services(self):
        """
        represent DAS services
        """
        dasdict = {}
        daskeys = set()
        dasmapkeys = self.dasmgr.mapping.dasmapscache.keys()
        dasmapkeys.sort()
        for key in dasmapkeys:
            srv, urn = key
            if srv not in self.dasmgr.systems:
                continue
            entry = self.dasmgr.mapping.dasmapscache[key]
            tmpdict = {}
            for item in entry["das_map"]:
                dkey = item["das_key"]
                rkey = item["rec_key"]
                daskeys.add(dkey)
                vlist = tmpdict.get(dkey, []) + [rkey]
                tmpdict[dkey] = list(set(vlist))
            apis = []
            if srv in dasdict:
                vdict = dasdict[srv]
                okeys = vdict["keys"]
                apis = vdict["apis"] + [urn]
                for kkk, vvv in okeys.iteritems():
                    vlist = tmpdict.get(kkk, []) + vvv
                    tmpdict[kkk] = list(set(vlist))
            else:
                apis = [urn]
            vdict = dict(keys=dict(tmpdict), apis=apis)
            dasdict[srv] = vdict
        mapreduce = [r for r in self.dasmgr.rawcache.get_map_reduce()]
        page = self.templatepage("das_services", dasdict=dasdict, daskeys=list(daskeys), mapreduce=mapreduce)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def api(self, system, name):
        """
        Return DAS mapping record about provided API.
        """
        record = self.dasmgr.mapping.api_info(system, name)
        page = "<b>DAS mapping record</b>"
        page += das_json_full(record)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def default(self, *args, **kwargs):
        """
        Default method.
        """
        return self.index(args, kwargs)

    def adjust_input(self, kwargs):
        """
        Adjust user input wrt common DAS keyword patterns, e.g.
        /Zee/*/* -> dataset=*Zee*, T1_US -> site=T1_US.

        More ambiguous input (such as Zee -> dataset=*Zee*) is however left
        to be handled by the keyword search.

        This is active only if adjust_input is set in DAS server configuration.
        """
        if not self.adjust:
            return
        uinput = kwargs.get("input", "")
        inst = kwargs.get("instance", self.dbs_global)

        kwargs["input"] = identify_apparent_query_patterns(uinput, inst)

    def _get_dbsmgr(self, inst):
        """
        Given a string representation of DBS instance, returns DBSManager
        instance which "knows" how to look up datasets
        """
        mgr = None
        # instance selection shall be more clean
        if not self.dataset_daemon:
            return mgr
        for dbs_url, dbs_inst in self.dbsmgr.keys():
            if dbs_inst == inst:
                return self.dbsmgr[(dbs_url, dbs_inst)]
        return mgr

    def _get_kws_host(self):
        """
        gets the host for keyword search from config. default is same server
        """
        return self.dasconfig["load_balance"]["kws_host"]

    def _get_autocompl_host(self):
        """
        gets the host for autocompletion from config. default is same server
        """
        conf = self.dasconfig.get("load_balance", {})
        return conf.get("autocompletion_host", "")

    def is_kws_enabled(self):
        """
        is keyword search client (ajax request) enabled
        """
        return self.dasconfig["keyword_search"]["kws_on"]

    def is_kws_service_enabled(self):
        """
        is keyword search service (response to ajax call) enabled
        """
        return self.dasconfig["keyword_search"]["kws_service_on"]

    def generate_dasquery(self, uinput, inst, html_mode=True):
        """
        Check provided input as valid DAS input query.
        Returns status and content (either error message or valid DASQuery)
        :param uinput: user's input
        :param inst: DBS instance
        :param html_mode: whether errors shall be output in html
        """

        def error_msg(msg, show_kws=False, tmpl="das_ambiguous", **kwargs):
            """
            Helper function which renders an error template, default is
            das_ambiguous, but can be overriden via tmpl param.
            Template has two versions: html and text for CLI.

            The template is passed with msg, base, guide, and **kwargs. """
            guide = self.templatepage("dbsql_vs_dasql", operators=", ".join(das_operators()))
            # render keyword search loader, if needed
            kws = ""
            if show_kws:
                kws = self.templatepage(
                    "kwdsearch_via_ajax", uinput=uinput, inst=inst or self.dbs_global, kws_host=self._get_kws_host()
                )
            # render the appropriate template (html vs text mode)
            page = self.templatepage(
                tmpl + ("_txt" if not html_mode else ""),
                msg=msg,
                base=self.base,
                guide=guide,
                kws_enabled=show_kws,
                kws=kws,
                **kwargs
            )
            return page

        if not uinput:
            return 1, error_msg("No input query")

        # Generate a DASQuery object, if it fails we catch the exception and
        # wrap it for upper layer (web interface)
        try:
            dasquery = DASQuery(uinput, instance=inst)
        except WildcardMultipleMatchesException as err:
            das_parser_error(uinput, str(err).replace("\n", ""))
            return 1, error_msg(str(err), tmpl="das_wildcard_err", suggest=err.options.values)
        except WildcardMatchingException as err:
            das_parser_error(uinput, str(type(err)) + " " + str(err))
            return 1, error_msg(str(err))
        except Exception as err:
            das_parser_error(uinput, str(type(err)) + " " + str(err))

            # show multiple dataset matches for 1 keyword queries
            if hasattr(response, "dataset_matches_msg"):
                return 1, error_msg(response.dataset_matches_msg, show_kws=self.is_kws_enabled())

            # for non Wildcard parsing errors, show the Keyword Search
            return 1, error_msg(str(err), show_kws=self.is_kws_enabled())

        # DAS query validation
        if isinstance(uinput, dict):  # DASQuery w/ {'spec':{'_id:id}}
            pass
        elif uinput.find("queries") != -1:
            pass
        elif uinput.find("records") != -1:
            pass
        else:  # normal user DAS query
            try:
                service_map = dasquery.service_apis_map()
            except Exception as exc:
                msg = "Fail to obtain service API map for this DASQuery"
                print msg
                print_exc(exc)
                return 1, error_msg(msg)
            if not service_map:
                return 1, error_msg("Unable to resolve the query over the " "available services: %s" % dasquery)
        return 0, dasquery

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def index(self, *args, **kwargs):
        """
        represents DAS web interface.
        It uses das_searchform template for
        input form and yui_table for output Table widget.
        """
        uinput = getarg(kwargs, "input", "")
        return self.page(self.form(uinput=uinput, cards=True))

    def form(self, uinput="", instance=None, view="list", cards=False):
        """
        provide input DAS search form
        """
        # TODO: rename into search_form()? (template is also called like this

        if "'" in uinput:  # e.g. file.creation_date>'20120101 12:01:01'
            uinput = uinput.replace("'", '"')
        if not instance:
            instance = self.dbs_global
        cards = self.templatepage(
            "das_cards", base=self.base, show=cards, width=900, height=220, cards=help_cards(self.base)
        )
        daskeys = self.templatepage("das_keys", daskeys=self.daskeyslist)
        page = self.templatepage(
            "das_searchform",
            input=uinput,
            init_dbses=list(self.dbs_instances),
            daskeys=daskeys,
            base=self.base,
            instance=instance,
            view=view,
            cards=cards,
            autocompl_host=json.dumps(self._get_autocompl_host()),
        )
        return page

    @expose
    def error(self, msg, wrap=True):
        """
        Show error message.
        """
        page = self.templatepage("das_error", msg=str(msg))
        if wrap:
            page = self.page(self.form() + page)
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def gridfs(self, **kwargs):
        """
        Retieve records from GridFS
        """
        time0 = time.time()
        if "fid" not in kwargs:
            code = web_code("No file id")
            raise HTTPError(500, "DAS error, code=%s" % code)
        fid = kwargs.get("fid")
        data = {"status": "requested", "fid": fid}
        try:
            fds = self.gfs.get(ObjectId(fid))
            return fds.read()
        except Exception as exc:
            print_exc(exc)
            code = web_code("Exception")
            raise HTTPError(500, "DAS error, code=%s" % code)
        data["ctime"] = time.time() - time0
        return json.dumps(data)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def records(self, *args, **kwargs):
        """
        Retieve all records id's.
        """
        try:
            recordid = None
            if args:
                recordid = args[0]
                spec = {"_id": ObjectId(recordid)}
                fields = None
                query = dict(fields=fields, spec=spec)
            elif kwargs and "_id" in kwargs:
                spec = {"_id": ObjectId(kwargs["_id"])}
                fields = None
                query = dict(fields=fields, spec=spec)
            else:  # return all ids
                query = dict(fields=None, spec={})

            res = ""
            time0 = time.time()
            idx = getarg(kwargs, "idx", 0)
            limit = getarg(kwargs, "limit", 10)
            coll = kwargs.get("collection", "merge")
            view = kwargs.get("view", "")
            if view == "json":
                res = []
            inst = kwargs.get("instance", self.dbs_global)
            form = self.form(uinput="")
            check, content = self.generate_dasquery(query, inst)
            if check:
                return self.page(form + content, ctime=time.time() - time0)
            dasquery = content  # returned content is valid DAS query
            nresults = self.dasmgr.rawcache.nresults(dasquery, coll)
            gen = self.dasmgr.rawcache.get_from_cache(dasquery, idx=idx, limit=limit, collection=coll)
            if recordid:  # we got id
                for row in gen:
                    if view == "json":
                        res.append(row)
                    else:
                        res += das_json(dasquery, row)
            else:
                for row in gen:
                    rid = row["_id"]
                    del row["_id"]
                    res += self.templatepage("das_record", id=rid, collection=coll, daskeys=", ".join(row))
            if recordid:
                page = res
            else:
                url = "/das/records?"
                if nresults:
                    page = self.templatepage("das_pagination", nrows=nresults, idx=idx, limit=limit, url=url)
                else:
                    page = "No results found, nresults=%s" % nresults
                page += res

            ctime = time.time() - time0
            if view == "json":
                return json.dumps(res)
            page = self.page(form + page, ctime=ctime)
            return page
        except Exception as exc:
            print_exc(exc)
            return self.error(gen_error_msg(kwargs))

    @jsonstreamer
    def datastream(self, kwargs):
        """Stream DAS data into JSON format"""
        head = kwargs.get("head", dict(timestamp=time.time()))
        if "mongo_query" not in head:
            head["mongo_query"] = head["dasquery"].mongo_query if "dasquery" in head else {}
        if "dasquery" in head:
            del head["dasquery"]
        if "args" in head:
            del head["args"]
        data = kwargs.get("data", [])
        if self.check_clients:
            # update client version
            cli, cli_msg = check_client_version()
            head.update({"client": cli, "client_message": cli_msg})
            # for old clients setup appropriate status/reason
            if cli_msg:
                head.update({"status": "warning", "reason": cli_msg})
        return head, data

    def get_data(self, kwargs):
        """
        Invoke DAS workflow and get data from the cache.
        """
        head = dict(timestamp=time.time())
        head["args"] = kwargs
        uinput = kwargs.get("input", "")
        inst = kwargs.get("instance", self.dbs_global)
        idx = getarg(kwargs, "idx", 0)
        limit = getarg(kwargs, "limit", 0)  # do not impose limit
        coll = kwargs.get("collection", "merge")
        status = kwargs.get("status")
        error = kwargs.get("error")
        reason = kwargs.get("reason")
        dasquery = kwargs.get("dasquery", None)
        time0 = time.time()
        if dasquery:
            dasquery = DASQuery(dasquery, instance=inst)
        else:
            check, content = self.generate_dasquery(uinput, inst, html_mode=False)
            if check:
                head.update({"status": "fail", "reason": content, "ctime": time.time() - time0, "input": uinput})
                data = []
                return head, data
            dasquery = content  # returned content is valid DAS query
        try:
            nres = self.dasmgr.nresults(dasquery, coll)
            data = self.dasmgr.get_from_cache(dasquery, idx, limit)
            # check that we got what we expected
            data = [r for r in data]
            if nres and not len(data):
                for retry in xrange(1, 3, 5):
                    msg = "retry in %s sec" % retry
                    print dastimestamp("DAS WARNING "), msg, dasquery
                    time.sleep(retry)  # retry one more time
                    data = self.dasmgr.get_from_cache(dasquery, idx, limit)
                    data = [r for r in data]
                    if len(data):
                        break
            if nres and not len(data):
                msg = "fail to get all data for %s, nres=%s, len(data)=%s" % (dasquery, nres, len(data))
                print dastimestamp("DAS WARNING "), msg
                status = "fail"
                reason = "Fail to retrieve data from DAS cache, please retry"

            if dasquery.aggregators:
                # aggregators split DAS record into sub-system and then
                # apply aggregator functions, therefore we need to correctly
                # account for nresults. Resolve generator into list and take
                # its length as nresults value.
                data = [r for r in data]
                nres = len(data)
            if error:  # DAS record contains an error
                status = "error"
            head.update({"status": status, "nresults": nres, "ctime": time.time() - time0, "dasquery": dasquery})
        except Exception as exc:
            status = "fail"
            reason = str(exc)
            print_exc(exc)
            head.update({"status": status, "ctime": time.time() - time0, "dasquery": dasquery})
            data = []
        head.update({"incache": self.dasmgr.incache(dasquery, coll="cache"), "apilist": self.dasmgr.apilist(dasquery)})
        if reason:
            head.update({"reason": reason})
        if status != "ok":
            head.update(self.info())
        return head, data

    def info(self):
        "Return status of DAS server"
        info = {"nrequests": self.reqmgr.size(), "nworkers": self.taskmgr.nworkers(), "dasweb": self.reqmgr.status()}
        if self.dasmgr and self.dasmgr.taskmgr:
            info.update({"dascore": self.dasmgr.taskmgr.status()})
        return dict(das_server=info)

    def busy(self):
        """
        Check server load and report busy status if
        nrequests - nworkers > queue limit
        """
        nrequests = self.reqmgr.size()
        if (nrequests - self.taskmgr.nworkers()) > self.queue_limit:
            msg = "#request=%s, queue_limit=%s, #workers=%s" % (nrequests, self.taskmgr.nworkers(), self.queue_limit)
            print dastimestamp("DAS WEB SERVER IS BUSY "), msg
            return True
        return False

    def busy_page(self, uinput=None):
        """DAS server busy page layout"""
        page = "<h3>DAS server is busy, please try later</h3>"
        form = self.form(uinput)
        return self.page(form + page)

    def _is_web_request(self, view):
        """
        returns whether the current view mode is not web
        """

        # first, check for explicit output type (view)

        if view in ["json", "xml", "plain"]:
            return False

        # check accept header - e.g. das client only provides accept header
        accepts = cherrypy.request.headers.elements("Accept")
        non_html_accepts = ["application/json"]
        other_accepted = [a for a in accepts if a.value not in non_html_accepts]

        # if only non html content types are accepted we are in non html mode
        if not other_accepted and accepts:
            return False

        return True

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def cache(self, **kwargs):
        """
        DAS web cache interface. Fire up new process for new requests and
        record its pid. The client is in charge to keep track of pid.
        The new process uses DAS core call to request the data into cache.
        Since query are cached the repeated call with the same query
        has no cost to DAS core.
        """
        # do not allow caching
        set_no_cache_flags()

        # if busy return right away
        if self.busy():
            nrequests = self.reqmgr.size()
            level = nrequests - self.taskmgr.nworkers() - self.queue_limit
            reason = "DAS server is busy"
            reason += ", #requests=%s, #workers=%s, queue size=%s" % (
                self.reqmgr.size(),
                self.taskmgr.nworkds(),
                self.queue_limit,
            )
            head = dict(timestamp=time.time())
            head.update({"status": "busy", "reason": reason, "ctime": 0})
            data = []
            return self.datastream(dict(head=head, data=data))

        uinput = kwargs.get("input", "").strip()
        if not uinput:
            head = {"status": "fail", "reason": "No input found", "args": kwargs, "ctime": 0, "input": uinput}
            data = []
            return self.datastream(dict(head=head, data=data))
        self.adjust_input(kwargs)
        pid = kwargs.get("pid", "")
        inst = kwargs.get("instance", self.dbs_global)
        uinput = kwargs.get("input", "")
        view = kwargs.get("view", "list")
        data = []

        # textual views need text only error messages...
        check, content = self.generate_dasquery(uinput, inst, html_mode=self._is_web_request(view))
        if check:
            head = dict(timestamp=time.time())
            head.update(
                {"status": "fail", "reason": "Can not interpret the query" + " (while creating DASQuery)", "ctime": 0}
            )
            if not self._is_web_request(view):
                head["error_details"] = content
                head["reason"] = head["reason"] + "\n\n" + content
            return self.datastream(dict(head=head, data=data))

        dasquery = content  # returned content is valid DAS query
        status, error, reason = self.dasmgr.get_status(dasquery)
        kwargs.update({"status": status, "error": error, "reason": reason})
        if not pid:
            pid = dasquery.qhash
        if status == None and not self.reqmgr.has_pid(pid):  # submit new request
            addr = cherrypy.request.headers.get("Remote-Addr")
            _evt, pid = self.taskmgr.spawn(self.dasmgr.call, dasquery, uid=addr, pid=dasquery.qhash)
            self.reqmgr.add(pid, kwargs)
            return pid
        if status == "ok":
            self.reqmgr.remove(pid)
            kwargs["dasquery"] = dasquery
            head, data = self.get_data(kwargs)
            return self.datastream(dict(head=head, data=data))
        kwargs["dasquery"] = dasquery.storage_query
        if not self.pid_pat.match(str(pid)) or len(str(pid)) != 32:
            self.reqmgr.remove(pid)
            head = {"status": "fail", "reason": "Invalid pid", "args": kwargs, "ctime": 0, "input": uinput}
            data = []
            return self.datastream(dict(head=head, data=data))
        elif self.taskmgr.is_alive(pid):
            return pid
        else:  # process is done, get data
            self.reqmgr.remove(pid)
            head, data = self.get_data(kwargs)
            return self.datastream(dict(head=head, data=data))

    def get_page_content(self, kwargs, complete_msg=True):
        """Retrieve page content for provided set of parameters"""
        page = ""
        try:
            view = kwargs.get("view", "list")
            if view == "plain":
                if "limit" in kwargs:
                    del kwargs["limit"]
            if view in ["json", "xml", "plain"] and complete_msg:
                page = "Request completed. Reload the page ..."
            else:
                head, data = self.get_data(kwargs)

                allowed_views = ["list", "table", "plain", "xml", "json"]
                if view not in allowed_views:
                    raise

                func = getattr(self, view + "view")
                page = func(head, data)
        except HTTPError as _err:
            raise
        except Exception as exc:
            print_exc(exc)
            msg = gen_error_msg(kwargs)
            page = self.templatepage("das_error", msg=msg)
        return page

    @expose
    def download(self, lfn):
        "DAS download page for given LFN"
        page = self.templatepage("filemover", lfn=lfn)
        return self.page(page, response_div=False)

    @expose
    def makepy(self, dataset, instance):
        """
        Request to create CMSSW py snippet for a given dataset
        """
        pat = re.compile("/.*/.*/.*")
        if not pat.match(dataset):
            msg = "Invalid dataset name"
            return self.error(msg)
        query = "file dataset=%s instance=%s | grep file.name" % (dataset, instance)
        try:
            data = self.dasmgr.result(query, idx=0, limit=0)
        except Exception as exc:
            print_exc(exc)
            msg = "Exception: %s\n" % str(exc)
            msg += "Unable to retrieve data for query=%s" % query
            return self.error(msg)
        lfns = []
        for rec in data:
            filename = DotDict(rec).get("file.name")
            if filename not in lfns:
                lfns.append(filename)
        page = self.templatepage("das_files_py", lfnList=lfns, pfnList=[])
        cherrypy.response.headers["Content-Type"] = "text/plain"
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def request(self, **kwargs):
        """
        Request data from DAS cache.
        """
        # do not allow caching
        set_no_cache_flags()

        uinput = kwargs.get("input", "").strip()
        if not uinput:
            kwargs["reason"] = "No input found"
            return self.redirect(**kwargs)

        # if busy return right away
        if self.busy():
            return self.busy_page(uinput)

        time0 = time.time()
        self.adjust_input(kwargs)
        view = kwargs.get("view", "list")
        inst = kwargs.get("instance", self.dbs_global)
        uinput = kwargs.get("input", "")
        form = self.form(uinput=uinput, instance=inst, view=view)
        check, content = self.generate_dasquery(uinput, inst)
        if check:
            if view == "list" or view == "table":
                return self.page(form + content, ctime=time.time() - time0)
            else:
                return content
        dasquery = content  # returned content is valid DAS query
        status, error, reason = self.dasmgr.get_status(dasquery)
        kwargs.update({"status": status, "error": error, "reason": reason})
        pid = dasquery.qhash
        if status == None:  # process new request
            kwargs["dasquery"] = dasquery.storage_query
            addr = cherrypy.request.headers.get("Remote-Addr")
            _evt, pid = self.taskmgr.spawn(self.dasmgr.call, dasquery, uid=addr, pid=dasquery.qhash)
            self.reqmgr.add(pid, kwargs)
        elif status == "ok" or status == "fail":
            self.reqmgr.remove(pid)

            # check if query can be rewritten via nested PK query
            rew_msg = self.q_rewriter and self.q_rewriter.check_fields(dasquery)
            if rew_msg:
                content = self.templatepage("das_error", msg=rew_msg)
                return self.page(form + content, ctime=time.time() - time0)

            kwargs["dasquery"] = dasquery
            page = self.get_page_content(kwargs, complete_msg=False)
            ctime = time.time() - time0
            if view == "list" or view == "table":
                return self.page(form + page, ctime=ctime)

            return page
        if self.taskmgr.is_alive(pid):
            page = self.templatepage(
                "das_check_pid",
                method="check_pid",
                uinput=uinput,
                view=view,
                base=self.base,
                pid=pid,
                interval=self.interval,
            )
        else:
            self.reqmgr.remove(pid)
            page = self.get_page_content(kwargs)
        ctime = time.time() - time0
        return self.page(form + page, ctime=ctime)

    @expose
    def status(self):
        """Return list of all current requests in DAS queue"""
        requests = [r for r in self.reqmgr.items()]
        page = self.templatepage("das_status", requests=requests)
        return self.page(page)

    @expose
    @checkargs(["pid"])
    def check_pid(self, pid):
        """
        Check status of given pid. This is a server callback
        function for ajaxCheckPid, see js/ajax_utils.js
        """
        # do not allow caching
        set_no_cache_flags()

        img = '<img src="%s/images/loading.gif" alt="loading"/>' % self.base
        page = ""
        try:
            if self.taskmgr.is_alive(pid):
                page = img + " processing PID=%s" % pid
            else:
                # at this point we don't know if request arrived to this host
                # or it was processed. To distinguish the case we'll ask
                # request manager for that pid
                if self.reqmgr.has_pid(pid):
                    self.reqmgr.remove(pid)
                    page = "Request PID=%s is completed" % pid
                    page += ", please wait for results to load"
                else:
                    # there're no request on this server, re-initiate it
                    ref = cherrypy.request.headers.get("Referer", None)
                    if ref:
                        url = urlparse(ref)
                        params = dict(parse_qsl(url.query))
                        return self.request(**params)
                    else:
                        msg = "No referer in cherrypy.request.headers"
                        msg += "\nHeaders: %s" % cherrypy.request.headers
                        print dastimestamp("DAS WEB ERROR "), msg
        except Exception as err:
            msg = "check_pid fails for pid=%s" % pid
            print dastimestamp("DAS WEB ERROR "), msg
            print_exc(err)
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)
            return self.error(gen_error_msg({"pid": pid}), wrap=False)
        return page

    def listview(self, head, data):
        """DAS listview data representation"""
        return self.repmgr.listview(head, data)

    def tableview(self, head, data):
        """DAS tabular view data representation"""
        return self.repmgr.tableview(head, data)

    def plainview(self, head, data):
        """DAS plain view data representation"""
        return self.repmgr.plainview(head, data)

    def xmlview(self, head, data):
        """DAS XML data representation"""
        return self.repmgr.xmlview(head, data)

    def jsonview(self, head, data):
        """DAS JSON data representation"""
        return self.repmgr.jsonview(head, data)

    @exposedasjson
    @enable_cross_origin
    @checkargs(["query", "dbs_instance"])
    def autocomplete(self, **kwargs):
        """
        Provides autocomplete functionality for DAS web UI.
        """
        query = kwargs.get("query", "").strip()
        result = autocomplete_helper(query, self.dasmgr, self.daskeys)
        dataset = [r for r in result if r["value"].find("dataset=") != -1]
        dbsinst = kwargs.get("dbs_instance", self.dbs_global)
        if self.dataset_daemon and len(dataset):
            dbsmgr = self._get_dbsmgr(dbsinst)
            if query.find("dataset=") != -1:
                query = query.replace("dataset=", "")
            for row in dbsmgr.find(query):
                result.append({"css": "ac-info", "value": "dataset=%s" % row, "info": "dataset"})
        return result
Example #8
0
 def setUp(self):
     """
     set up stuff
     """
     self.reqmgr = RequestManager(lifetime=0)
Example #9
0
class testDAS_RegMgr(unittest.TestCase):
    """
    A test class for the DAS RequestManager
    """
    def setUp(self):
        """
        set up stuff
        """
        self.reqmgr = RequestManager(lifetime=0)

    def test_reqmgr(self):
        """Test reqmgr methods"""
        pid  = 1
        kwds = {'uinput':'bla'}
        self.reqmgr.add(pid, kwds)
        result = self.reqmgr.get(pid)
        self.assertEqual(kwds, result)

        self.reqmgr.remove(pid)
        result = self.reqmgr.get(pid)
        self.assertEqual(None, result)

    def test_reqmgr_tstamp(self):
        """Test reqmgr methods"""
        pid  = 1
        kwds = {'input':'bla'}
        self.reqmgr.add(pid, kwds)
        result = self.reqmgr.get(pid)
        self.assertEqual(kwds, result)
        time.sleep(1)
        self.reqmgr.clean()
        result = [r for r in self.reqmgr.items()]
        self.assertEqual([], result)
Example #10
0
 def setUp(self):
     """
     set up stuff
     """
     self.reqmgr = RequestManager(lifetime=0)
Example #11
0
class testDAS_RegMgr(unittest.TestCase):
    """
    A test class for the DAS RequestManager
    """
    def setUp(self):
        """
        set up stuff
        """
        self.reqmgr = RequestManager(lifetime=0)

    def test_reqmgr(self):
        """Test reqmgr methods"""
        pid = 1
        kwds = {'uinput': 'bla'}
        self.reqmgr.add(pid, kwds)
        result = self.reqmgr.get(pid)
        self.assertEqual(kwds, result)

        self.reqmgr.remove(pid)
        result = self.reqmgr.get(pid)
        self.assertEqual(None, result)

    def test_reqmgr_tstamp(self):
        """Test reqmgr methods"""
        pid = 1
        kwds = {'input': 'bla'}
        self.reqmgr.add(pid, kwds)
        result = self.reqmgr.get(pid)
        self.assertEqual(kwds, result)
        time.sleep(1)
        self.reqmgr.clean()
        result = [r for r in self.reqmgr.items()]
        self.assertEqual([], result)
Example #12
0
class DASWebService(DASWebManager):
    """
    DAS web service interface.
    """
    def __init__(self, dasconfig):
        DASWebManager.__init__(self, dasconfig)
        config = dasconfig['web_server']
        self.pid_pat     = re.compile(r'^[a-z0-9]{32}')
        self.base        = config['url_base']
        self.interval    = config.get('status_update', 2500)
        self.engine      = config.get('engine', None)
        nworkers         = config['number_of_workers']
        self.hot_thr     = config.get('hot_threshold', 3000)
        self.dasconfig   = dasconfig
        self.dburi       = self.dasconfig['mongodb']['dburi']
        self.lifetime    = self.dasconfig['mongodb']['lifetime']
        self.queue_limit = config.get('queue_limit', 50)
        if  self.engine:
            thr_name = 'DASWebService:PluginTaskManager'
            self.taskmgr = PluginTaskManager(\
                        bus=self.engine, nworkers=nworkers, name=thr_name)
            self.taskmgr.subscribe()
        else:
            thr_name = 'DASWebService:TaskManager'
            self.taskmgr = TaskManager(nworkers=nworkers, name=thr_name)
        self.adjust      = config.get('adjust_input', False)

        self.init()

        # Monitoring thread which performs auto-reconnection
        thread.start_new_thread(dascore_monitor, \
                ({'das':self.dasmgr, 'uri':self.dburi}, self.init, 5))

        # Obtain DBS global instance or set it as None
        if  self.dasconfig.has_key('dbs'):
            self.dbs_global = \
                self.dasconfig['dbs'].get('dbs_global_instance', None)
            self.dbs_instances = \
                self.dasconfig['dbs'].get('dbs_instances', [])
        else:
            self.dbs_global = None
            self.dbs_instances = []

        # Start DBS daemon
        self.dataset_daemon = config.get('dbs_daemon', False)
        if  self.dataset_daemon:
            self.dbs_daemon(config)

    def process_requests_onhold(self):
        "Process requests which are on hold"
        try:
            limit = self.queue_limit/2
            thread.start_new_thread(onhold_worker, \
                (self.dasmgr, self.taskmgr, self.reqmgr, limit))
        except Exception as exc:
            print_exc(exc)

    def dbs_daemon(self, config):
        """Start DBS daemon if it is requested via DAS configuration"""
        try:
            main_dbs_url = self.dasconfig['dbs']['dbs_global_url']
            self.dbs_urls = []
            for inst in self.dbs_instances:
                self.dbs_urls.append(\
                        main_dbs_url.replace(self.dbs_global, inst))
            interval  = config.get('dbs_daemon_interval', 3600)
            dbsexpire = config.get('dbs_daemon_expire', 3600)
            self.dbsmgr = {} # dbs_urls vs dbs_daemons
            if  self.dataset_daemon:
                for dbs_url in self.dbs_urls:
                    dbsmgr = DBSDaemon(dbs_url, self.dburi, expire=dbsexpire)
                    self.dbsmgr[dbs_url] = dbsmgr
                    def dbs_updater(_dbsmgr, interval):
                        """DBS updater daemon"""
                        while True:
                            try:
                                _dbsmgr.update()
                            except:
                                pass
                            time.sleep(interval)
                    print "Start DBSDaemon for %s" % dbs_url
                    thread.start_new_thread(dbs_updater, (dbsmgr, interval, ))
        except Exception as exc:
            print_exc(exc)

    def init(self):
        """Init DAS web server, connect to DAS Core"""
        try:
            self.logcol     = DASLogdb(self.dasconfig)
            self.reqmgr     = RequestManager(self.dburi, lifetime=self.lifetime)
            self.dasmgr     = DASCore(engine=self.engine)
            self.repmgr     = CMSRepresentation(self.dasconfig, self.dasmgr)
            self.daskeys    = self.dasmgr.das_keys()
            self.gfs        = db_gridfs(self.dburi)
            self.daskeys.sort()
            self.dasmapping = self.dasmgr.mapping
            self.dasmapping.init_presentationcache()
            self.colors = {}
            for system in self.dasmgr.systems:
                self.colors[system] = gen_color(system)
            self.sitedbmgr   = SiteDBService(self.dasconfig)
        except Exception as exc:
            print_exc(exc)
            self.dasmgr = None
            self.daskeys = []
            self.colors = {}
            return
        # Start Onhold_request daemon
        if  self.dasconfig['web_server'].get('onhold_daemon', False):
            self.process_requests_onhold()

    def logdb(self, query):
        """
        Make entry in Logging DB
        """
        qhash = genkey(query)
        args  = cherrypy.request.params
        doc = dict(qhash=qhash,
                date=int(str(date.fromtimestamp(time.time())).replace('-', '')),
                headers=cherrypy.request.headers,
                method=cherrypy.request.method,
                path=cherrypy.request.path_info,
                args=args, ahash=genkey(args),
                ip=cherrypy.request.remote.ip,
                hostname=cherrypy.request.remote.name,
                port=cherrypy.request.remote.port)
        self.logcol.insert('web', doc)

    def get_nhits(self):
        "Return number of hits per day client made"
        tsec  = time.mktime(date.timetuple(date.today()))
        spec  = {'ip': cherrypy.request.remote.ip, 'ts': {'$gte': tsec},
                 'args.pid': {'$exists': False}, # do not count pid requests
                 'path': '/cache'} # requests from das_client calls
        nhits = self.logcol.find(spec, count=True)
        return nhits

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def redirect(self, **kwargs):
        """
        Represent DAS redirect page
        """
        dmsg = 'You do not have permission to access the resource requested.'
        msg  = kwargs.get('reason', dmsg)
        if  msg:
            msg = 'Reason: ' + msg
        page = self.templatepage('das_redirect', msg=msg)
        return self.page(page, response_div=False)

    def bottom(self, response_div=True):
        """
        Define footer for all DAS web pages
        """
        return self.templatepage('das_bottom', div=response_div,
                version=DAS.version)

    def page(self, content, ctime=None, response_div=True):
        """
        Define footer for all DAS web pages
        """
        page  = self.top()
        page += content
        page += self.templatepage('das_bottom', ctime=ctime, 
                                  version=DAS.version, div=response_div)
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS + ['section', 'highlight'])
    def faq(self, *args, **kwargs):
        """
        represent DAS FAQ.
        """
        section = kwargs.get('section', None)
        highlight = kwargs.get('highlight', None)
        guide = self.templatepage('dbsql_vs_dasql', 
                    operators=', '.join(das_operators()))
        page = self.templatepage('das_faq', guide=guide,
                section=section, highlight=highlight,
                operators=', '.join(das_operators()), 
                aggregators=', '.join(das_aggregators()))
        return self.page(page, response_div=False)

    @expose
    def cli(self):
        """
        Serve DAS CLI file download.
        """
        dasroot = '/'.join(__file__.split('/')[:-3])
        clifile = os.path.join(dasroot, 'DAS/tools/das_client.py')
        return serve_file(clifile, content_type='text/plain')

    @expose
    def movetodas(self):
        "Placeholder page for DBS to DAS migration"
        style = "width:600px;margin-left:auto;margin-right:auto;padding-top:20px"
        page  = """<div style="%s">""" % style
        page += "Dear user,<br/>DBS Data Discovery page is depricated.<br/>"
        page += "Please migrate to Data Aggregation Service located at"
        page += "<p>https://cmsweb.cern.ch/das/</p>"
        page += "<em>CMS HTTP group.</em>"
        page += "</div>"""
        return page

    @expose
    def opensearch(self):
        """
        Serve DAS opensearch file.
        """
        if  self.base and self.base.find('http://') != -1:
            base = self.base
        else:
            base = 'http://cmsweb.cern.ch/das'
        desc = self.templatepage('das_opensearch', base=base)
        cherrypy.response.headers['Content-Type'] = \
                'application/opensearchdescription+xml'
        return desc

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def services(self, *args, **kwargs):
        """
        represent DAS services
        """
        dasdict = {}
        daskeys = []
        for system, keys in self.dasmgr.mapping.daskeys().iteritems():
            if  system not in self.dasmgr.systems:
                continue
            tmpdict = {}
            for key in keys:
                tmpdict[key] = self.dasmgr.mapping.lookup_keys(system, key) 
                if  key not in daskeys:
                    daskeys.append(key)
            dasdict[system] = dict(keys=dict(tmpdict), 
                apis=self.dasmgr.mapping.list_apis(system))
        mapreduce = [r for r in self.dasmgr.rawcache.get_map_reduce()]
        page = self.templatepage('das_services', dasdict=dasdict, 
                        daskeys=daskeys, mapreduce=mapreduce)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def api(self, name, **kwargs):
        """
        Return DAS mapping record about provided API.
        """
        record = self.dasmgr.mapping.api_info(name)
        page   = "<b>DAS mapping record</b>"
        page  += das_json(record)
        return self.page(page, response_div=False)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def default(self, *args, **kwargs):
        """
        Default method.
        """
        return self.index(args, kwargs)

    def adjust_input(self, kwargs):
        """
        Adjust user input wrt common DAS keyword patterns, e.g.
        Zee -> dataset=*Zee*, T1_US -> site=T1_US*. This method
        only works if self.adjust is set in configuration of DAS server.
        This method can be customization for concrete DAS applications via
        external free_text_parser function (part of DAS.web.utils module)
        """
        if  not self.adjust:
            return
        uinput = kwargs.get('input', '')
        query_part = uinput.split('|')[0]
        if  query_part == 'queries' or query_part == 'records':
            return
        new_input = free_text_parser(uinput, self.daskeys)
        if  uinput and new_input == uinput:
            selkey = choose_select_key(uinput, self.daskeys, 'dataset')
            if  selkey and len(new_input) > len(selkey) and \
                new_input[:len(selkey)] != selkey:
                new_input = selkey + ' ' + new_input
        kwargs['input'] = new_input

    def generate_dasquery(self, uinput, inst, html_error=True):
        """
        Check provided input as valid DAS input query.
        Returns status and content (either error message or valid DASQuery)
        """
        def helper(msg, html_error=None):
            """Helper function which provide error template"""
            if  not html_error:
                return msg
            guide = self.templatepage('dbsql_vs_dasql', 
                        operators=', '.join(das_operators()))
            page = self.templatepage('das_ambiguous', msg=msg, base=self.base,
                        guide=guide)
            return page
        if  not uinput:
            return 1, helper('No input query')
        # Generate DASQuery object, if it fails we catch the exception and
        # wrap it for upper layer (web interface)
        try:
            dasquery = DASQuery(uinput, instance=inst)
        except Exception as err:
            return 1, helper(das_parser_error(uinput, str(err)), html_error)
        fields = dasquery.mongo_query.get('fields', [])
        if  not fields:
            fields = []
        spec   = dasquery.mongo_query.get('spec', {})
        for word in fields+spec.keys():
            found = 0
            if  word in DAS_DB_KEYWORDS:
                found = 1
            for key in self.daskeys:
                if  word.find(key) != -1:
                    found = 1
            if  not found:
                msg = 'Provided input does not contain a valid DAS key'
                return 1, helper(msg, html_error)
        if  isinstance(uinput, dict): # DASQuery w/ {'spec':{'_id:id}}
            pass
        elif uinput.find('queries') != -1:
            pass
        elif uinput.find('records') != -1:
            pass
        else: # normal user DAS query
            try:
                service_map = dasquery.service_apis_map()
            except Exception as exc:
                msg = 'Fail to lookup DASQuery service API map'
                print msg
                print_exc(exc)
                return 1, helper(msg, html_error)
            if  not service_map:
                msg  = "None of the API's registered in DAS "
                msg += "can resolve this query"
                return 1, helper(msg, html_error)
        return 0, dasquery

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def index(self, *args, **kwargs):
        """
        represents DAS web interface. 
        It uses das_searchform template for
        input form and yui_table for output Table widget.
        """
        uinput = getarg(kwargs, 'input', '') 
        return self.page(self.form(uinput=uinput, cards=True))

    def form(self, uinput='', instance=None, view='list', cards=False):
        """
        provide input DAS search form
        """
        if  not instance:
            instance = self.dbs_global
        cards = self.templatepage('das_cards', base=self.base, show=cards, \
                width=900, height=220, cards=help_cards(self.base))
        page  = self.templatepage('das_searchform', input=uinput, \
                init_dbses=list(self.dbs_instances), \
                base=self.base, instance=instance, view=view, cards=cards)
        return page

    @expose
    def error(self, msg, wrap=True):
        """
        Show error message.
        """
        page = self.templatepage('das_error', msg=str(msg))
        if  wrap:
            page  = self.page(self.form() + page)
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def gridfs(self, *args, **kwargs):
        """
        Retieve records from GridFS
        """
        time0 = time.time()
        if  not kwargs.has_key('fid'):
            code = web_code('No file id')
            raise HTTPError(500, 'DAS error, code=%s' % code)
        fid  = kwargs.get('fid')
        data = {'status':'requested', 'fid':fid}
        try:
            fds = self.gfs.get(ObjectId(fid))
            return fds.read()
        except Exception as exc:
            print_exc(exc)
            code = web_code('Exception')
            raise HTTPError(500, 'DAS error, code=%s' % code)
        data['ctime'] = time.time() - time0
        return json.dumps(data)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def records(self, *args, **kwargs):
        """
        Retieve all records id's.
        """
        try:
            recordid = None
            if  args:
                recordid = args[0]
                spec = {'_id':ObjectId(recordid)}
                fields = None
                query = dict(fields=fields, spec=spec)
            elif  kwargs and kwargs.has_key('_id'):
                spec = {'_id': ObjectId(kwargs['_id'])}
                fields = None
                query = dict(fields=fields, spec=spec)
            else: # return all ids
                query = dict(fields=None, spec={})

            res      = ''
            time0    = time.time()
            idx      = getarg(kwargs, 'idx', 0)
            limit    = getarg(kwargs, 'limit', 10)
            coll     = kwargs.get('collection', 'merge')
            inst     = kwargs.get('instance', self.dbs_global)
            form     = self.form(uinput="")
            check, content = self.generate_dasquery(query, inst)
            if  check:
                return self.page(form + content, ctime=time.time()-time0)
            dasquery = content # returned content is valid DAS query
            nresults = self.dasmgr.rawcache.nresults(dasquery, coll)
            gen      = self.dasmgr.rawcache.get_from_cache\
                (dasquery, idx=idx, limit=limit, collection=coll)
            if  recordid: # we got id
                for row in gen:
                    res += das_json(row)
            else:
                for row in gen:
                    rid  = row['_id']
                    del row['_id']
                    res += self.templatepage('das_record', \
                            id=rid, collection=coll, daskeys=', '.join(row))
            if  recordid:
                page  = res
            else:
                url   = '/das/records?'
                if  nresults:
                    page = self.templatepage('das_pagination', \
                        nrows=nresults, idx=idx, limit=limit, url=url)
                else:
                    page = 'No results found, nresults=%s' % nresults
                page += res

            ctime   = (time.time()-time0)
            page = self.page(form + page, ctime=ctime)
            return page
        except Exception as exc:
            print_exc(exc)
            return self.error(gen_error_msg(kwargs))

    @jsonstreamer
    def datastream(self, kwargs):
        """Stream DAS data into JSON format"""
        head = kwargs.get('head', dict(timestamp=time.time()))
        if  not head.has_key('mongo_query'):
            head['mongo_query'] = head['dasquery'].mongo_query \
                if head.has_key('dasquery') else {}
        if  head.has_key('dasquery'):
            del head['dasquery']
        if  head.has_key('args'):
            del head['args']
        data = kwargs.get('data', [])
        return head, data

    def get_data(self, kwargs):
        """
        Invoke DAS workflow and get data from the cache.
        """
        head   = dict(timestamp=time.time())
        head['args'] = kwargs
        uinput = kwargs.get('input', '')
        inst   = kwargs.get('instance', self.dbs_global)
        idx    = getarg(kwargs, 'idx', 0)
        limit  = getarg(kwargs, 'limit', 0) # do not impose limit
        coll   = kwargs.get('collection', 'merge')
        dasquery = kwargs.get('dasquery', None)
        time0  = time.time()
        if  dasquery:
            dasquery = DASQuery(dasquery, instance=inst)
        else:
            check, content = \
                    self.generate_dasquery(uinput, inst, html_error=False)
            if  check:
                head.update({'status': 'fail', 'reason': content,
                             'ctime': time.time()-time0, 'input': uinput})
                data = []
                return head, data
            dasquery = content # returned content is valid DAS query
        try:
            nres = self.dasmgr.nresults(dasquery, coll)
            data = \
                self.dasmgr.get_from_cache(dasquery, idx, limit)
            head.update({'status':'ok', 'nresults':nres,
                         'ctime': time.time()-time0, 'dasquery': dasquery})
        except Exception as exc:
            print_exc(exc)
            head.update({'status': 'fail', 'reason': str(exc),
                         'ctime': time.time()-time0, 'dasquery': dasquery})
            data = []
        head.update({'incache':self.dasmgr.incache(dasquery, coll='cache')})
        return head, data

    def busy(self):
        """
        Check number server load and report busy status if it's
        above threashold = queue size - nworkers
        """
        nrequests = self.reqmgr.size()
        if  (nrequests - self.taskmgr.nworkers()) > self.queue_limit:
            return True
        return False

    def busy_page(self, uinput=None):
        """DAS server busy page layout"""
        page = "<h3>DAS server is busy, please try later</h3>"
        form = self.form(uinput)
        return self.page(form + page)

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def cache(self, **kwargs):
        """
        DAS web cache interface. Fire up new process for new requests and
        record its pid. The client is in charge to keep track of pid.
        The new process uses DAS core call to request the data into cache.
        Since query are cached the repeated call with the same query
        has no cost to DAS core.
        """
        # remove expires records from merge collection
        self.dasmgr.rawcache.remove_expired('merge')

        # do not allow caching
        cherrypy.response.headers['Cache-Control'] = 'no-cache'
        cherrypy.response.headers['Pragma'] = 'no-cache'
        uinput = kwargs.get('input', '').strip()
        if  not uinput:
            head = {'status': 'fail', 'reason': 'No input found',
                    'args': kwargs, 'ctime': 0, 'input': uinput}
            data = []
            return self.datastream(dict(head=head, data=data))
        self.adjust_input(kwargs)
        pid    = kwargs.get('pid', '')
        inst   = kwargs.get('instance', self.dbs_global)
        uinput = kwargs.get('input', '')
        data   = []
        check, content = self.generate_dasquery(uinput, inst)
        if  check:
            head = dict(timestamp=time.time())
            head.update({'status': 'fail',
                         'reason': 'Fail to create DASQuery object',
                         'ctime': 0})
            return self.datastream(dict(head=head, data=data))
        dasquery = content # returned content is valid DAS query
        status, qhash = self.dasmgr.get_status(dasquery)
        if  status == 'ok':
            self.reqmgr.remove(dasquery.qhash)
            head, data = self.get_data(kwargs)
            return self.datastream(dict(head=head, data=data))
        kwargs['dasquery'] = dasquery.storage_query
        if  not pid and self.busy():
            head = dict(timestamp=time.time())
            head.update({'status': 'busy', 'reason': 'DAS server is busy',
                         'ctime': 0})
            return self.datastream(dict(head=head, data=data))
        if  pid:
            if  not self.pid_pat.match(str(pid)) or len(str(pid)) != 32:
                head = {'status': 'fail', 'reason': 'Invalid pid',
                        'args': kwargs, 'ctime': 0, 'input': uinput}
                data = []
                return self.datastream(dict(head=head, data=data))
            elif self.taskmgr.is_alive(pid):
                return pid
            else: # process is done, get data
                self.reqmgr.remove(pid)
                head, data = self.get_data(kwargs)
                return self.datastream(dict(head=head, data=data))
        else:
            config = self.dasconfig.get('cacherequests', {})
            thr = threshold(self.sitedbmgr, self.hot_thr, config)
            nhits = self.get_nhits()
            if  nhits > thr: # exceed threshold
                if  self.busy(): # put request onhold, server is busy
                    tstamp = time.time() + 60*(nhits/thr) + (nhits%thr)
                    pid  = dasquery.qhash
                    self.reqmgr.add_onhold(\
                        pid, uinput, cherrypy.request.remote.ip, tstamp)
                    head = {'status':'onhold',
                            'mongo_query':dasquery.mongo_query,
                            'pid':pid, 'nresults':0, 'ctime':0,
                            'timestamp':time.time()}
                    data = []
                    return self.datastream(dict(head=head, data=data))
            addr = cherrypy.request.headers.get('Remote-Addr')
            _evt, pid = self.taskmgr.spawn(\
                self.dasmgr.call, dasquery, addr, pid=dasquery.qhash)
            self.logdb(uinput) # put entry in log DB once we place a request
            self.reqmgr.add(pid, kwargs)
            return pid

    def get_page_content(self, kwargs, complete_msg=True):
        """Retrieve page content for provided set of parameters"""
        page = ''
        try:
            view = kwargs.get('view', 'list')
            if  view == 'plain':
                if  kwargs.has_key('limit'):
                    del kwargs['limit']
            if  view in ['json', 'xml', 'plain'] and complete_msg:
                page = 'Request comlpeted. Reload the page ...'
            else:
                head, data = self.get_data(kwargs)
                func = getattr(self, view + "view")
                page = func(head, data)
        except HTTPError as _err:
            raise 
        except Exception as exc:
            print_exc(exc)
            msg  = gen_error_msg(kwargs)
            page = self.templatepage('das_error', msg=msg)
        return page

    @expose
    def makepy(self, dataset, instance):
        """
        Request to create CMSSW py snippet for a given dataset
        """
        pat = re.compile('/.*/.*/.*')
        if  not pat.match(dataset):
            msg = 'Invalid dataset name'
            return self.error(msg)
        query = "file dataset=%s instance=%s | grep file.name" \
                % (dataset, instance)
        try:
            data   = self.dasmgr.result(query, idx=0, limit=0)
        except Exception as exc:
            print_exc(exc)
            msg    = 'Exception: %s\n' % str(exc)
            msg   += 'Unable to retrieve data for query=%s' % query
            return self.error(msg)
        lfns = []
        for rec in data:
            filename = DotDict(rec).get('file.name')
            if  filename not in lfns:
                lfns.append(filename)
        page = self.templatepage('das_files_py', lfnList=lfns, pfnList=[])
        cherrypy.response.headers['Content-Type'] = "text/plain"
        return page

    @expose
    @checkargs(DAS_WEB_INPUTS)
    def request(self, **kwargs):
        """
        Request data from DAS cache.
        """
        # remove expires records from merge collection
        self.dasmgr.rawcache.remove_expired('merge')

        # do not allow caching
        cherrypy.response.headers['Cache-Control'] = 'no-cache'
        cherrypy.response.headers['Pragma'] = 'no-cache'

        uinput  = kwargs.get('input', '').strip()
        if  not uinput:
            kwargs['reason'] = 'No input found'
            return self.redirect(**kwargs)

        time0   = time.time()
        self.adjust_input(kwargs)
        view    = kwargs.get('view', 'list')
        inst    = kwargs.get('instance', self.dbs_global)
        uinput  = kwargs.get('input', '')
        if  self.busy():
            return self.busy_page(uinput)
        ahash    = genkey(cherrypy.request.params)
        self.logdb(uinput)
        form    = self.form(uinput=uinput, instance=inst, view=view)
        check, content = self.generate_dasquery(uinput, inst)
        if  check:
            if  view == 'list' or view == 'table':
                return self.page(form + content, ctime=time.time()-time0)
            else:
                return content
        dasquery = content # returned content is valid DAS query
        status, qhash = self.dasmgr.get_status(dasquery)
        if  status == 'ok':
            page = self.get_page_content(kwargs, complete_msg=False)
            ctime = (time.time()-time0)
            if  view == 'list' or view == 'table':
                return self.page(form + page, ctime=ctime)
            return page
        else:
            kwargs['dasquery'] = dasquery.storage_query
            addr = cherrypy.request.headers.get('Remote-Addr')
            _evt, pid = self.taskmgr.spawn(self.dasmgr.call, dasquery, addr,
                                pid=dasquery.qhash)
            self.reqmgr.add(pid, kwargs)
            if  self.taskmgr.is_alive(pid):
                page = self.templatepage('das_check_pid', method='check_pid',
                        uinput=uinput, view=view, ahash=ahash,
                        base=self.base, pid=pid, interval=self.interval)
            else:
                page = self.get_page_content(kwargs)
                self.reqmgr.remove(pid)
        ctime = (time.time()-time0)
        return self.page(form + page, ctime=ctime)

    @expose
    def requests(self):
        """Return list of all current requests in DAS queue"""
        page = ""
        count = 0
        for row in self.reqmgr.items():
            page += '<li>%s placed at %s<br/>%s</li>' \
                        % (row['_id'], row['timestamp'], row['kwds'])
            count += 1
        if  page:
            page = "<ul>%s</ul>" % page
        else:
            page = "The request queue is empty"
        if  count:
            page += '<div>Total: %s requests</div>' % count
        return self.page(page)

    @expose
    @checkargs(['pid', 'ahash'])
    def check_pid(self, pid, ahash):
        """
        Check status of given pid and return appropriate page content.
        This is a server callback function for ajaxCheckPid, see
        js/ajax_utils.js
        """
        cherrypy.response.headers['Cache-Control'] = 'no-cache'
        cherrypy.response.headers['Pragma'] = 'no-cache'
        img  = '<img src="%s/images/loading.gif" alt="loading"/>' % self.base
        page = ''
        try:
            if  self.taskmgr.is_alive(pid):
                page = img + " processing PID=%s" % pid
            else:
                kwargs = self.reqmgr.get(pid)
                if  kwargs and kwargs.has_key('dasquery'):
                    del kwargs['dasquery']
                # if no kwargs (another request delete it)
                # use logging DB to look-up user request via ahash
                if  not kwargs:
                    spec = {'ahash':ahash}
                    skey = [('ts', DESCENDING)]
                    res  = [r for r in self.logcol.find(spec).sort(skey)]
                    kwargs = res[0]['args']
                    self.adjust_input(kwargs)
                self.reqmgr.remove(pid)
                page = self.get_page_content(kwargs)
        except Exception as err:
            msg = 'check_pid fails for pid=%s' % pid
            print dastimestamp('DAS WEB ERROR '), msg
            print_exc(err)
            self.reqmgr.remove(pid)
            self.taskmgr.remove(pid)
            return self.error(gen_error_msg({'pid':pid}), wrap=False)
        return page

    def listview(self, head, data):
        """DAS listview data representation"""
        return self.repmgr.listview(head, data)

    def tableview(self, head, data):
        """DAS tabular view data representation"""
        return self.repmgr.tableview(head, data)

    def plainview(self, head, data):
        """DAS plain view data representation"""
        return self.repmgr.plainview(head, data)

    def xmlview(self, head, data):
        """DAS XML data representation"""
        return self.repmgr.xmlview(head, data)

    def jsonview(self, head, data):
        """DAS JSON data representation"""
        return self.repmgr.jsonview(head, data)

    @exposedasjson
    @checkargs(['query', 'dbs_instance'])
    def autocomplete(self, **kwargs):
        """
        Provides autocomplete functionality for DAS web UI.
        """
        query = kwargs.get("query", "").strip()
        result = autocomplete_helper(query, self.dasmgr, self.daskeys)
        dataset = [r for r in result if r['value'].find('dataset=')!=-1]
        dbsinst = kwargs.get('dbs_instance', self.dbs_global)
        if  self.dataset_daemon and len(dataset):
            dbs_urls = [d for d in self.dbsmgr.keys() if d.find(dbsinst) != -1]
            if  len(dbs_urls) == 1:
                dbsmgr = self.dbsmgr[dbs_urls[0]]
                if  query.find('dataset=') != -1:
                    query = query.replace('dataset=', '')
                for row in dbsmgr.find(query):
                    result.append({'css': 'ac-info',
                                   'value': 'dataset=%s' % row,
                                   'info': 'dataset'})
        return result