def __init__(self, logger=None, reset_storage=False, storage=None):
if not logger:
logger = logging.getLogger('hostpool.rest.backend')
self.logger = logger.getChild('backend')
self.logger.setLevel(logging.DEBUG)
self.storage = Database(storage)
if reset_storage:
with FLOCK.acquire(timeout=10):
self.storage.init_data()
class RestBackend(object):
'''RESTful service backend class'''
def __init__(self, logger=None, reset_storage=False, storage=None):
if not logger:
logger = logging.getLogger('hostpool.rest.backend')
self.logger = logger.getChild('backend')
self.logger.setLevel(logging.DEBUG)
self.storage = Database(storage)
if reset_storage:
with FLOCK.acquire(timeout=10):
self.storage.init_data()
def list_hosts(self, filters=None):
'''Get an iterable of all hosts'''
self.logger.debug('backend.list_hosts()')
return [x for x in self.storage.get_hosts()
if self.check_host_by_filters(x, filters)]
def add_hosts(self, config):
'''Adds hosts to the host pool'''
self.logger.debug('backend.add_hosts({0})'.format(config))
if not isinstance(config, dict) or \
not config.get('hosts'):
raise exceptions.HostPoolHTTPException('Invalid hosts format')
hosts = HostAlchemist(config).parse()
return self.storage.add_hosts(hosts)
def remove_host(self, host_id):
'''Remove a host from the host pool'''
self.logger.debug('backend.remove_host({0})'.format(host_id))
if not host_id or not isinstance(host_id, int):
raise exceptions.HostNotFoundException(host_id)
h_id = self.storage.remove_host(host_id)
if not h_id:
raise exceptions.HostNotFoundException(host_id)
return h_id
def update_host(self, host_id, updates):
'''Updates a host in the host pool'''
self.logger.debug('backend.update_host({0})'.format(host_id))
if not host_id or not isinstance(host_id, int):
raise exceptions.HostNotFoundException(host_id)
if not isinstance(updates, dict):
raise exceptions.HostPoolHTTPException('Invalid data format')
orig = self.storage.get_host(host_id)
if not orig:
raise exceptions.HostNotFoundException(host_id)
updated = dict_update(orig, updates)
h_id = self.storage.update_host(host_id, updated)
if not h_id:
raise exceptions.HostNotFoundException(host_id)
return h_id
def check_host_by_filters(self, host, filters):
'''Check if a host matches a set of filters'''
# Basic validation
if not filters or not isinstance(filters, dict):
self.logger.warn('No filters specified')
return True
if not host:
self.logger.warn('No host specified')
return False
# Check filters using a True fall-through
# Check OS
if filters.get('os'):
if not isinstance(filters.get('os'), basestring):
self.logger.warn('Invalid, non-string requested OS provided')
return False
if filters.get('os').lower() != host.get('os', '').lower():
self.logger.warn('Host does not match all filters '
'(os={0})'.format(filters.get('os').lower()))
return False
# Check tags (AND method)
if filters.get('tags'):
if not isinstance(filters.get('tags'), list):
self.logger.warn('Invalid, non-list requested tags provided')
return False
for tag in filters.get('tags'):
if tag not in host.get('tags', list()):
self.logger.warn('Host does not match all filters '
'(tags={0})'.format(filters.get('tags')))
return False
return True
def acquire_host(self, filters=None):
'''Acquire a host, mark it taken'''
# Format the OS request
self.logger.debug('backend.acquire_host({0})'.format(filters))
for host_id in self.get_unallocated_host_ids():
# Allocate the host
self.logger.debug('Trying host #{0}'.format(host_id))
self.storage.update_host(host_id, {'allocated': True})
# Refresh our data
host = self.storage.get_host(host_id)
# Enforce any user-defined requests
if self.check_host_by_filters(host, filters) and \
self.host_port_scan(host['endpoint']):
return self.storage.get_host(host_id)
self.storage.update_host(host_id, {'allocated': False})
# We didn't manage to acquire any host
raise exceptions.NoHostAvailableException()
def release_host(self, host_id):
'''Release a host, free it'''
if not host_id or not isinstance(host_id, int):
raise exceptions.HostNotFoundException(host_id)
self.storage.update_host(host_id, {'allocated': False})
return self.storage.get_host(host_id)
def get_host(self, host_id):
'''Gets a host + key data'''
self.logger.debug('backend.get_host({0})'.format(host_id))
if not host_id or not isinstance(host_id, int):
raise exceptions.HostNotFoundException(host_id)
host = self.storage.get_host(host_id)
if not host:
raise exceptions.HostNotFoundException(host_id)
return host
def get_unallocated_host_ids(self):
'''Get a generator for free hosts'''
hosts = self.list_hosts()
for host in hosts:
if not host['allocated']:
yield host[constants.HOST_ID_KEY]
def host_port_scan(self, endpoint):
'''Scans a TCP port'''
# Basic validation
if not endpoint or not endpoint.get('ip') or not endpoint.get('port'):
self.logger.error('Invalid endpoint specified')
return False
# Creates a TCP socket
sock = socket.socket()
sock.settimeout(1)
self.logger.info('Testing endpoint tcp://{0}:{1}'.format(
endpoint['ip'], endpoint['port']))
try:
sock.connect((endpoint['ip'], endpoint['port']))
sock.close()
self.logger.info('Successfully connected to '
'endpoint tcp://{0}:{1}'.format(
endpoint['ip'], endpoint['port']))
return True
except socket.error as exc:
self.logger.warn('Error connecting to endpoint tcp://{0}:{1}. '
'Exception: {2}'.format(
endpoint['ip'], endpoint['port'], exc))
return False
