def __init__(self, fconf, handler):
"""
Initialize a MasterServer instance
@param fconf the path to the configuration file
@param handler the handler object in charge of managing HTTP requests
"""
Logger.__init__(self, "Manager")
conf = json.load(open(fconf))
# Jinja2 initialization.
tmpl_path = os.path.join(os.path.dirname(os.path.abspath(__file__)),
'templates')
self.env = Environment(loader=FileSystemLoader(tmpl_path))
self.status = ApplicationStatus()
# This is a dictionary structure in the form
# reduce_dict["group-name"] = [
# [ file list by unique integers, size in byte
# ] => Reduce-0
# [
# ] => Reduce-1
# ]
self.reduce_mark = set()
self.reduce_dict = defaultdict(list)
self.dead_reduce_dict = defaultdict(list)
# This is a dictionary nick => Handler instance
self.masters = {}
self.last_id = -1
self.pending_works = defaultdict(list) # nick => [work, ...]
self.ping_max = int(conf["ping-max"])
self.ping_interval = int(conf["ping-interval"])
self.num_reducer = int(conf["num-reducer"])
# This will just keep track of the name of the files
self.reduce_files = []
self.results_printed = False
for _ in range(self.num_reducer):
self.reduce_files.append("N/A")
# Load the input module and assing the generator to the work_queue
module = load_module(conf["input-module"])
cls = getattr(module, "Input", None)
# Some code for the DFS
generator = cls(fconf).input()
self.use_dfs = use_dfs = conf['dfs-enabled']
if use_dfs:
dfsconf = conf['dfs-conf']
dfsconf['host'] = dfsconf['master']
self.path = conf['output-prefix']
else:
dfsconf = None
self.path = os.path.join(
os.path.join(conf['datadir'], conf['output-prefix'])
)
self.work_queue = WorkQueue(self.logger, generator, use_dfs, dfsconf)
# Lock to synchronize access to the timestamps dictionary
self.lock = Lock()
self.timestamps = {} # nick => (send_ts:enum, ts:float)
# Ping thread
self.hb_thread = Thread(target=self.hearthbeat)
# Event to mark the end of the server
self.finished = Event()
self.addrinfo = (conf['master-host'], conf['master-port'])
Server.__init__(self, self.addrinfo[0], self.addrinfo[1], handler)
class MasterServer(Server, Logger):
def __init__(self, fconf, handler):
"""
Initialize a MasterServer instance
@param fconf the path to the configuration file
@param handler the handler object in charge of managing HTTP requests
"""
Logger.__init__(self, "Manager")
conf = json.load(open(fconf))
# Jinja2 initialization.
tmpl_path = os.path.join(os.path.dirname(os.path.abspath(__file__)),
'templates')
self.env = Environment(loader=FileSystemLoader(tmpl_path))
self.status = ApplicationStatus()
# This is a dictionary structure in the form
# reduce_dict["group-name"] = [
# [ file list by unique integers, size in byte
# ] => Reduce-0
# [
# ] => Reduce-1
# ]
self.reduce_mark = set()
self.reduce_dict = defaultdict(list)
self.dead_reduce_dict = defaultdict(list)
# This is a dictionary nick => Handler instance
self.masters = {}
self.last_id = -1
self.pending_works = defaultdict(list) # nick => [work, ...]
self.ping_max = int(conf["ping-max"])
self.ping_interval = int(conf["ping-interval"])
self.num_reducer = int(conf["num-reducer"])
# This will just keep track of the name of the files
self.reduce_files = []
self.results_printed = False
for _ in range(self.num_reducer):
self.reduce_files.append("N/A")
# Load the input module and assing the generator to the work_queue
module = load_module(conf["input-module"])
cls = getattr(module, "Input", None)
# Some code for the DFS
generator = cls(fconf).input()
self.use_dfs = use_dfs = conf['dfs-enabled']
if use_dfs:
dfsconf = conf['dfs-conf']
dfsconf['host'] = dfsconf['master']
self.path = conf['output-prefix']
else:
dfsconf = None
self.path = os.path.join(
os.path.join(conf['datadir'], conf['output-prefix'])
)
self.work_queue = WorkQueue(self.logger, generator, use_dfs, dfsconf)
# Lock to synchronize access to the timestamps dictionary
self.lock = Lock()
self.timestamps = {} # nick => (send_ts:enum, ts:float)
# Ping thread
self.hb_thread = Thread(target=self.hearthbeat)
# Event to mark the end of the server
self.finished = Event()
self.addrinfo = (conf['master-host'], conf['master-port'])
Server.__init__(self, self.addrinfo[0], self.addrinfo[1], handler)
def run(self):
"Start the server"
# Just redirects every message logged to the application status object
# in order to make it available through the web interface
self.logger.addHandler(PushHandler(self.status.push_log))
if self.work_queue.use_dfs:
self.info("Starting Distributed Filesystem")
self.work_queue.fs.start()
self.info("Server started on http://%s:%d" % self.addrinfo)
self.hb_thread.start()
Server.run(self)
def stop(self):
"Stop the server"
self.finished.set()
if self.work_queue.use_dfs:
self.work_queue.fs.stop()
def retrieve_file(self, nick, reduce_idx, file):
fid, fsize = file
fname = get_file_name(self.path, reduce_idx, fid)
self.reduce_files[reduce_idx] = (nick, fname, fsize)
def print_results(self):
if self.results_printed:
return
if not self.reduce_mark and not self.dead_reduce_dict and \
self.status.phase == self.status.PHASE_MERGE:
self.results_printed = True
for nick, fname, fsize in self.reduce_files:
self.info("Group %s produced %s [%d bytes] output file" % \
(nick, fname, fsize))
def on_group_died(self, nick, is_error):
"""
Called whenever a master disconnected from the server
@param nick the nick of the master dying
@param is_error a boolean indicating if this was an abnormal error or
whether the socket was safely shutted down.
"""
# NB: Possibly we can restart the master through a bash script or
# provide to the final user an overridable method in order to manage
# the situation and apply different policies.
self.status.update_master_status(nick, {'status': 'dead'})
self.status.faults += 1
# Remove any pending map activity
lst = self.pending_works[nick]
del self.pending_works[nick]
for wstatus in lst:
self.status.map_faulted += 1
self.work_queue.push(wstatus.state)
# Remove any pending reduce activity
lst = self.reduce_dict[nick]
if lst: # This might be None
self.dead_reduce_dict[nick] = lst
for reducer_lst in lst:
if reducer_lst:
self.status.reduce_faulted += 1
del self.reduce_dict[nick]
del self.masters[nick]
def hearthbeat(self):
"""
This method is executed in an external thread namely the hearthbeat
thread. The aim of the code is to periodically ping all the masters.
"""
while not self.finished.is_set():
with self.lock:
for nick in self.masters:
self.timestamps[nick] = (PING_EXECUTE, 0)
time.sleep(self.ping_interval)
# Here we do not do anything if a given master overflows a specific
# the specified limit but just warn the user about the violation.
with self.lock:
for nick in self.masters:
status, rtt = self.timestamps.get(nick, (None, None))
if status is not None and rtt > self.ping_max:
self.warning(
"RTT for %s is above the limit (%.2f > %.2f)" % \
(nick, rtt, self.ping_max)
)
