""" kombu.connection ================ Broker connection and pools. """ from __future__ import absolute_import import os import socket from contextlib import contextmanager from itertools import count, cycle from operator import itemgetter # jython breaks on relative import for .exceptions for some reason # (Issue #112) from kombu import exceptions from .five import Empty, range, string_t, text_t, LifoQueue as _LifoQueue from .log import get_logger from .transport import get_transport_cls, supports_librabbitmq from .utils import cached_property, retry_over_time, shufflecycle, HashedSeq from .utils.compat import OrderedDict from .utils.functional import lazy from .utils.url import as_url, parse_url, quote, urlparse __all__ = ['Connection', 'ConnectionPool', 'ChannelPool'] RESOLVE_ALIASES = {'pyamqp': 'amqp', 'librabbitmq': 'amqp'} _LOG_CONNECTION = os.environ.get('KOMBU_LOG_CONNECTION', False) _LOG_CHANNEL = os.environ.get('KOMBU_LOG_CHANNEL', False) logger = get_logger(__name__) roundrobin_failover = cycle failover_strategies = { 'round-robin': roundrobin_failover, 'shuffle': shufflecycle, } class Connection(object): """A connection to the broker. :param URL: Broker URL, or a list of URLs, e.g. .. code-block:: python Connection('amqp://guest:guest@localhost:5672//') Connection('amqp://foo;amqp://bar', failover_strategy='round-robin') Connection('redis://', transport_options={ 'visibility_timeout': 3000, }) import ssl Connection('amqp://', login_method='EXTERNAL', ssl={ 'ca_certs': '/etc/pki/tls/certs/something.crt', 'keyfile': '/etc/something/system.key', 'certfile': '/etc/something/system.cert', 'cert_reqs': ssl.CERT_REQUIRED, }) .. admonition:: SSL compatibility SSL currently only works with the py-amqp, amqplib, and qpid transports. For other transports you can use stunnel. :keyword ssl: Use SSL to connect to the server. Default is ``False``. May not be supported by the specified transport. :keyword transport: Default transport if not specified in the URL. :keyword connect_timeout: Timeout in seconds for connecting to the server. May not be supported by the specified transport. :keyword transport_options: A dict of additional connection arguments to pass to alternate kombu channel implementations. Consult the transport documentation for available options. :keyword heartbeat: Heartbeat interval in int/float seconds. Note that if heartbeats are enabled then the :meth:`heartbeat_check` method must be called regularly, around once per second. .. note:: The connection is established lazily when needed. If you need the connection to be established, then force it by calling :meth:`connect`:: >>> conn = Connection('amqp://') >>> conn.connect() and always remember to close the connection:: >>> conn.release() *Legacy options* These options have been replaced by the URL argument, but are still supported for backwards compatibility: :keyword hostname: Host name/address. NOTE: You cannot specify both the URL argument and use the hostname keyword argument at the same time. :keyword userid: Default user name if not provided in the URL. :keyword password: Default password if not provided in the URL. :keyword virtual_host: Default virtual host if not provided in the URL. :keyword port: Default port if not provided in the URL. """ port = None virtual_host = '/' connect_timeout = 5 _closed = None _connection = None _default_channel = None _transport = None _logger = False uri_prefix = None #: The cache of declared entities is per connection, #: in case the server loses data. declared_entities = None #: Iterator returning the next broker URL to try in the event #: of connection failure (initialized by :attr:`failover_strategy`). cycle = None #: Additional transport specific options, #: passed on to the transport instance. transport_options = None #: Strategy used to select new hosts when reconnecting after connection #: failure. One of "round-robin", "shuffle" or any custom iterator #: constantly yielding new URLs to try. failover_strategy = 'round-robin' #: Map of failover strategy name to Callable failover_strategies = failover_strategies #: Heartbeat value, currently only supported by the py-amqp transport. heartbeat = None hostname = userid = password = ssl = login_method = None def __init__(self, hostname='localhost', userid=None, password=None, virtual_host=None, port=None, insist=False, ssl=False, transport=None, connect_timeout=5, transport_options=None, login_method=None, uri_prefix=None, heartbeat=0, failover_strategy='round-robin', alternates=None, **kwargs): alt = [] if alternates is None else alternates # have to spell the args out, just to get nice docstrings :( params = self._initial_params = { 'hostname': hostname, 'userid': userid, 'password': password, 'virtual_host': virtual_host, 'port': port, 'insist': insist, 'ssl': ssl, 'transport': transport, 'connect_timeout': connect_timeout, 'login_method': login_method, 'heartbeat': heartbeat } if hostname and not isinstance(hostname, string_t): alt.extend(hostname) hostname = alt[0] if hostname and '://' in hostname: if ';' in hostname: alt.extend(hostname.split(';')) hostname = alt[0] if '+' in hostname[:hostname.index('://')]: # e.g. sqla+mysql://root:masterkey@localhost/ params['transport'], params['hostname'] = \ hostname.split('+', 1) transport = self.uri_prefix = params['transport'] else: transport = transport or urlparse(hostname).scheme if not get_transport_cls(transport).can_parse_url: # we must parse the URL params.update(parse_url(hostname)) params['transport'] = transport self._init_params(**params) # fallback hosts self.alt = alt self._failover_strategy_arg = failover_strategy or 'round-robin' self.failover_strategy = self.failover_strategies.get( self._failover_strategy_arg) or failover_strategy if self.alt: self.cycle = self.failover_strategy(self.alt) next(self.cycle) # skip first entry if transport_options is None: transport_options = {} self.transport_options = transport_options if _LOG_CONNECTION: # pragma: no cover self._logger = True if uri_prefix: self.uri_prefix = uri_prefix self.declared_entities = set() def switch(self, url): """Switch connection parameters to use a new URL (does not reconnect)""" self.close() self.declared_entities.clear() self._closed = False self._init_params(**dict(self._initial_params, **parse_url(url))) def maybe_switch_next(self): """Switch to next URL given by the current failover strategy (if any).""" if self.cycle: self.switch(next(self.cycle)) def _init_params(self, hostname, userid, password, virtual_host, port, insist, ssl, transport, connect_timeout, login_method, heartbeat): transport = transport or 'amqp' if transport == 'amqp' and supports_librabbitmq(): transport = 'librabbitmq' self.hostname = hostname self.userid = userid self.password = password self.login_method = login_method self.virtual_host = virtual_host or self.virtual_host self.port = port or self.port self.insist = insist self.connect_timeout = connect_timeout self.ssl = ssl self.transport_cls = transport self.heartbeat = heartbeat and float(heartbeat) def register_with_event_loop(self, loop): self.transport.register_with_event_loop(self.connection, loop) def _debug(self, msg, *args, **kwargs): if self._logger: # pragma: no cover fmt = '[Kombu connection:0x{id:x}] {msg}' logger.debug(fmt.format(id=id(self), msg=text_t(msg)), *args, **kwargs) def connect(self): """Establish connection to server immediately.""" self._closed = False return self.connection def channel(self): """Create and return a new channel.""" self._debug('create channel') chan = self.transport.create_channel(self.connection) if _LOG_CHANNEL: # pragma: no cover from .utils.debug import Logwrapped return Logwrapped(chan, 'kombu.channel', '[Kombu channel:{0.channel_id}] ') return chan def heartbeat_check(self, rate=2): """Allow the transport to perform any periodic tasks required to make heartbeats work. This should be called approximately every second. If the current transport does not support heartbeats then this is a noop operation. :keyword rate: Rate is how often the tick is called compared to the actual heartbeat value. E.g. if the heartbeat is set to 3 seconds, and the tick is called every 3 / 2 seconds, then the rate is 2. This value is currently unused by any transports. """ return self.transport.heartbeat_check(self.connection, rate=rate) def drain_events(self, **kwargs): """Wait for a single event from the server. :keyword timeout: Timeout in seconds before we give up. :raises :exc:`socket.timeout`: if the timeout is exceeded. """ return self.transport.drain_events(self.connection, **kwargs) def maybe_close_channel(self, channel): """Close given channel, but ignore connection and channel errors.""" try: channel.close() except (self.connection_errors + self.channel_errors): pass def _do_close_self(self): # Close only connection and channel(s), but not transport. self.declared_entities.clear() if self._default_channel: self.maybe_close_channel(self._default_channel) if self._connection: try: self.transport.close_connection(self._connection) except self.connection_errors + (AttributeError, socket.error): pass self._connection = None def _close(self): """Really close connection, even if part of a connection pool.""" self._do_close_self() if self._transport: self._transport.client = None self._transport = None self._debug('closed') self._closed = True def collect(self, socket_timeout=None): # amqp requires communication to close, we don't need that just # to clear out references, Transport._collect can also be implemented # by other transports that want fast after fork try: gc_transport = self._transport._collect except AttributeError: _timeo = socket.getdefaulttimeout() socket.setdefaulttimeout(socket_timeout) try: self._close() except socket.timeout: pass finally: socket.setdefaulttimeout(_timeo) else: gc_transport(self._connection) if self._transport: self._transport.client = None self._transport = None self.declared_entities.clear() self._connection = None def release(self): """Close the connection (if open).""" self._close() close = release def ensure_connection(self, errback=None, max_retries=None, interval_start=2, interval_step=2, interval_max=30, callback=None): """Ensure we have a connection to the server. If not retry establishing the connection with the settings specified. :keyword errback: Optional callback called each time the connection can't be established. Arguments provided are the exception raised and the interval that will be slept ``(exc, interval)``. :keyword max_retries: Maximum number of times to retry. If this limit is exceeded the connection error will be re-raised. :keyword interval_start: The number of seconds we start sleeping for. :keyword interval_step: How many seconds added to the interval for each retry. :keyword interval_max: Maximum number of seconds to sleep between each retry. :keyword callback: Optional callback that is called for every internal iteration (1 s) """ def on_error(exc, intervals, retries, interval=0): round = self.completes_cycle(retries) if round: interval = next(intervals) if errback: errback(exc, interval) self.maybe_switch_next() # select next host return interval if round else 0 retry_over_time(self.connect, self.recoverable_connection_errors, (), {}, on_error, max_retries, interval_start, interval_step, interval_max, callback) return self def completes_cycle(self, retries): """Return true if the cycle is complete after number of `retries`.""" return not (retries + 1) % len(self.alt) if self.alt else True def revive(self, new_channel): """Revive connection after connection re-established.""" if self._default_channel: self.maybe_close_channel(self._default_channel) self._default_channel = None def _default_ensure_callback(self, exc, interval): logger.error("Ensure: Operation error: %r. Retry in %ss", exc, interval, exc_info=True) def ensure(self, obj, fun, errback=None, max_retries=None, interval_start=1, interval_step=1, interval_max=1, on_revive=None): """Ensure operation completes, regardless of any channel/connection errors occurring. Will retry by establishing the connection, and reapplying the function. :param fun: Method to apply. :keyword errback: Optional callback called each time the connection can't be established. Arguments provided are the exception raised and the interval that will be slept ``(exc, interval)``. :keyword max_retries: Maximum number of times to retry. If this limit is exceeded the connection error will be re-raised. :keyword interval_start: The number of seconds we start sleeping for. :keyword interval_step: How many seconds added to the interval for each retry. :keyword interval_max: Maximum number of seconds to sleep between each retry. **Example** This is an example ensuring a publish operation:: >>> from kombu import Connection, Producer >>> conn = Connection('amqp://') >>> producer = Producer(conn) >>> def errback(exc, interval): ... logger.error('Error: %r', exc, exc_info=1) ... logger.info('Retry in %s seconds.', interval) >>> publish = conn.ensure(producer, producer.publish, ... errback=errback, max_retries=3) >>> publish({'hello': 'world'}, routing_key='dest') """ def _ensured(*args, **kwargs): got_connection = 0 conn_errors = self.recoverable_connection_errors chan_errors = self.recoverable_channel_errors has_modern_errors = hasattr( self.transport, 'recoverable_connection_errors', ) for retries in count(0): # for infinity try: return fun(*args, **kwargs) except conn_errors as exc: if got_connection and not has_modern_errors: # transport can not distinguish between # recoverable/irrecoverable errors, so we propagate # the error if it persists after a new connection was # successfully established. raise if max_retries is not None and retries > max_retries: raise self._debug('ensure connection error: %r', exc, exc_info=1) self._connection = None self._do_close_self() errback and errback(exc, 0) remaining_retries = None if max_retries is not None: remaining_retries = max(max_retries - retries, 1) self.ensure_connection(errback, remaining_retries, interval_start, interval_step, interval_max) new_channel = self.channel() self.revive(new_channel) obj.revive(new_channel) if on_revive: on_revive(new_channel) got_connection += 1 except chan_errors as exc: if max_retries is not None and retries > max_retries: raise self._debug('ensure channel error: %r', exc, exc_info=1) errback and errback(exc, 0) _ensured.__name__ = "%s(ensured)" % fun.__name__ _ensured.__doc__ = fun.__doc__ _ensured.__module__ = fun.__module__ return _ensured def autoretry(self, fun, channel=None, **ensure_options): """Decorator for functions supporting a ``channel`` keyword argument. The resulting callable will retry calling the function if it raises connection or channel related errors. The return value will be a tuple of ``(retval, last_created_channel)``. If a ``channel`` is not provided, then one will be automatically acquired (remember to close it afterwards). See :meth:`ensure` for the full list of supported keyword arguments. Example usage:: channel = connection.channel() try: ret, channel = connection.autoretry(publish_messages, channel) finally: channel.close() """ channels = [channel] create_channel = self.channel class Revival(object): __name__ = getattr(fun, '__name__', None) __module__ = getattr(fun, '__module__', None) __doc__ = getattr(fun, '__doc__', None) def revive(self, channel): channels[0] = channel def __call__(self, *args, **kwargs): if channels[0] is None: self.revive(create_channel()) return fun(*args, channel=channels[0], **kwargs), channels[0] revive = Revival() return self.ensure(revive, revive, **ensure_options) def create_transport(self): return self.get_transport_cls()(client=self) def get_transport_cls(self): """Get the currently used transport class.""" transport_cls = self.transport_cls if not transport_cls or isinstance(transport_cls, string_t): transport_cls = get_transport_cls(transport_cls) return transport_cls def clone(self, **kwargs): """Create a copy of the connection with the same connection settings.""" return self.__class__(**dict(self._info(resolve=False), **kwargs)) def get_heartbeat_interval(self): return self.transport.get_heartbeat_interval(self.connection) def _info(self, resolve=True): transport_cls = self.transport_cls if resolve: transport_cls = RESOLVE_ALIASES.get(transport_cls, transport_cls) D = self.transport.default_connection_params hostname = self.hostname or D.get('hostname') if self.uri_prefix: hostname = '%s+%s' % (self.uri_prefix, hostname) info = ( ('hostname', hostname), ('userid', self.userid or D.get('userid')), ('password', self.password or D.get('password')), ('virtual_host', self.virtual_host or D.get('virtual_host')), ('port', self.port or D.get('port')), ('insist', self.insist), ('ssl', self.ssl), ('transport', transport_cls), ('connect_timeout', self.connect_timeout), ('transport_options', self.transport_options), ('login_method', self.login_method or D.get('login_method')), ('uri_prefix', self.uri_prefix), ('heartbeat', self.heartbeat), ('failover_strategy', self._failover_strategy_arg), ('alternates', self.alt), ) return info def info(self): """Get connection info.""" return OrderedDict(self._info()) def __eqhash__(self): return HashedSeq(self.transport_cls, self.hostname, self.userid, self.password, self.virtual_host, self.port, repr(self.transport_options)) def as_uri(self, include_password=False, mask='**', getfields=itemgetter('port', 'userid', 'password', 'virtual_host', 'transport')): """Convert connection parameters to URL form.""" hostname = self.hostname or 'localhost' if self.transport.can_parse_url: if self.uri_prefix: return '%s+%s' % (self.uri_prefix, hostname) return self.hostname if self.uri_prefix: return '%s+%s' % (self.uri_prefix, hostname) fields = self.info() port, userid, password, vhost, transport = getfields(fields) return as_url( transport, hostname, port, userid, password, quote(vhost), sanitize=not include_password, mask=mask, ) def Pool(self, limit=None, preload=None): """Pool of connections. See :class:`ConnectionPool`. :keyword limit: Maximum number of active connections. Default is no limit. :keyword preload: Number of connections to preload when the pool is created. Default is 0. *Example usage*:: >>> connection = Connection('amqp://') >>> pool = connection.Pool(2) >>> c1 = pool.acquire() >>> c2 = pool.acquire() >>> c3 = pool.acquire() Traceback (most recent call last): File "", line 1, in File "kombu/connection.py", line 354, in acquire raise ConnectionLimitExceeded(self.limit) kombu.exceptions.ConnectionLimitExceeded: 2 >>> c1.release() >>> c3 = pool.acquire() """ return ConnectionPool(self, limit, preload) def ChannelPool(self, limit=None, preload=None): """Pool of channels. See :class:`ChannelPool`. :keyword limit: Maximum number of active channels. Default is no limit. :keyword preload: Number of channels to preload when the pool is created. Default is 0. *Example usage*:: >>> connection = Connection('amqp://') >>> pool = connection.ChannelPool(2) >>> c1 = pool.acquire() >>> c2 = pool.acquire() >>> c3 = pool.acquire() Traceback (most recent call last): File "", line 1, in File "kombu/connection.py", line 354, in acquire raise ChannelLimitExceeded(self.limit) kombu.connection.ChannelLimitExceeded: 2 >>> c1.release() >>> c3 = pool.acquire() """ return ChannelPool(self, limit, preload) def Producer(self, channel=None, *args, **kwargs): """Create new :class:`kombu.Producer` instance using this connection.""" from .messaging import Producer return Producer(channel or self, *args, **kwargs) def Consumer(self, queues=None, channel=None, *args, **kwargs): """Create new :class:`kombu.Consumer` instance using this connection.""" from .messaging import Consumer return Consumer(channel or self, queues, *args, **kwargs) def SimpleQueue(self, name, no_ack=None, queue_opts=None, exchange_opts=None, channel=None, **kwargs): """Create new :class:`~kombu.simple.SimpleQueue`, using a channel from this connection. If ``name`` is a string, a queue and exchange will be automatically created using that name as the name of the queue and exchange, also it will be used as the default routing key. :param name: Name of the queue/or a :class:`~kombu.Queue`. :keyword no_ack: Disable acknowledgements. Default is false. :keyword queue_opts: Additional keyword arguments passed to the constructor of the automatically created :class:`~kombu.Queue`. :keyword exchange_opts: Additional keyword arguments passed to the constructor of the automatically created :class:`~kombu.Exchange`. :keyword channel: Custom channel to use. If not specified the connection default channel is used. """ from .simple import SimpleQueue return SimpleQueue(channel or self, name, no_ack, queue_opts, exchange_opts, **kwargs) def SimpleBuffer(self, name, no_ack=None, queue_opts=None, exchange_opts=None, channel=None, **kwargs): """Create new :class:`~kombu.simple.SimpleQueue` using a channel from this connection. Same as :meth:`SimpleQueue`, but configured with buffering semantics. The resulting queue and exchange will not be durable, also auto delete is enabled. Messages will be transient (not persistent), and acknowledgements are disabled (``no_ack``). """ from .simple import SimpleBuffer return SimpleBuffer(channel or self, name, no_ack, queue_opts, exchange_opts, **kwargs) def _establish_connection(self): self._debug('establishing connection...') conn = self.transport.establish_connection() self._debug('connection established: %r', conn) return conn def __repr__(self): """``x.__repr__() <==> repr(x)``""" return ''.format(self.as_uri(), id(self)) def __copy__(self): """``x.__copy__() <==> copy(x)``""" return self.clone() def __reduce__(self): return self.__class__, tuple(self.info().values()), None def __enter__(self): return self def __exit__(self, *args): self.release() @property def qos_semantics_matches_spec(self): return self.transport.qos_semantics_matches_spec(self.connection) @property def connected(self): """Return true if the connection has been established.""" return (not self._closed and self._connection is not None and self.transport.verify_connection(self._connection)) @property def connection(self): """The underlying connection object. .. warning:: This instance is transport specific, so do not depend on the interface of this object. """ if not self._closed: if not self.connected: self.declared_entities.clear() self._default_channel = None self._connection = self._establish_connection() self._closed = False return self._connection @property def default_channel(self): """Default channel, created upon access and closed when the connection is closed. Can be used for automatic channel handling when you only need one channel, and also it is the channel implicitly used if a connection is passed instead of a channel, to functions that require a channel. """ # make sure we're still connected, and if not refresh. self.connection if self._default_channel is None: self._default_channel = self.channel() return self._default_channel @property def host(self): """The host as a host name/port pair separated by colon.""" return ':'.join([self.hostname, str(self.port)]) @property def transport(self): if self._transport is None: self._transport = self.create_transport() return self._transport @cached_property def manager(self): """Experimental manager that can be used to manage/monitor the broker instance. Not available for all transports.""" return self.transport.manager def get_manager(self, *args, **kwargs): return self.transport.get_manager(*args, **kwargs) @cached_property def recoverable_connection_errors(self): """List of connection related exceptions that can be recovered from, but where the connection must be closed and re-established first.""" try: return self.transport.recoverable_connection_errors except AttributeError: # There were no such classification before, # and all errors were assumed to be recoverable, # so this is a fallback for transports that do # not support the new recoverable/irrecoverable classes. return self.connection_errors + self.channel_errors @cached_property def recoverable_channel_errors(self): """List of channel related exceptions that can be automatically recovered from without re-establishing the connection.""" try: return self.transport.recoverable_channel_errors except AttributeError: return () @cached_property def connection_errors(self): """List of exceptions that may be raised by the connection.""" return self.transport.connection_errors @cached_property def channel_errors(self): """List of exceptions that may be raised by the channel.""" return self.transport.channel_errors @property def supports_heartbeats(self): return self.transport.supports_heartbeats @property def is_evented(self): return self.transport.supports_ev BrokerConnection = Connection class Resource(object): LimitExceeded = exceptions.LimitExceeded def __init__(self, limit=None, preload=None): self.limit = limit self.preload = preload or 0 self._closed = False self._resource = _LifoQueue() self._dirty = set() self.setup() def setup(self): raise NotImplementedError('subclass responsibility') def _add_when_empty(self): if self.limit and len(self._dirty) >= self.limit: raise self.LimitExceeded(self.limit) # All taken, put new on the queue and # try get again, this way the first in line # will get the resource. self._resource.put_nowait(self.new()) def acquire(self, block=False, timeout=None): """Acquire resource. :keyword block: If the limit is exceeded, block until there is an available item. :keyword timeout: Timeout to wait if ``block`` is true. Default is :const:`None` (forever). :raises LimitExceeded: if block is false and the limit has been exceeded. """ if self._closed: raise RuntimeError('Acquire on closed pool') if self.limit: while 1: try: R = self._resource.get(block=block, timeout=timeout) except Empty: self._add_when_empty() else: try: R = self.prepare(R) except BaseException: if isinstance(R, lazy): # no evaluated yet, just put it back self._resource.put_nowait(R) else: # evaluted so must try to release/close first. self.release(R) raise self._dirty.add(R) break else: R = self.prepare(self.new()) def release(): """Release resource so it can be used by another thread. The caller is responsible for discarding the object, and to never use the resource again. A new resource must be acquired if so needed. """ self.release(R) R.release = release return R def prepare(self, resource): return resource def close_resource(self, resource): resource.close() def release_resource(self, resource): pass def replace(self, resource): """Replace resource with a new instance. This can be used in case of defective resources.""" if self.limit: self._dirty.discard(resource) self.close_resource(resource) def release(self, resource): if self.limit: self._dirty.discard(resource) self._resource.put_nowait(resource) self.release_resource(resource) else: self.close_resource(resource) def collect_resource(self, resource): pass def force_close_all(self): """Close and remove all resources in the pool (also those in use). Can be used to close resources from parent processes after fork (e.g. sockets/connections). """ self._closed = True dirty = self._dirty resource = self._resource while 1: # - acquired try: dres = dirty.pop() except KeyError: break try: self.collect_resource(dres) except AttributeError: # Issue #78 pass while 1: # - available # deque supports '.clear', but lists do not, so for that # reason we use pop here, so that the underlying object can # be any object supporting '.pop' and '.append'. try: res = resource.queue.pop() except IndexError: break try: self.collect_resource(res) except AttributeError: pass # Issue #78 if os.environ.get('KOMBU_DEBUG_POOL'): # pragma: no cover _orig_acquire = acquire _orig_release = release _next_resource_id = 0 def acquire(self, *args, **kwargs): # noqa import traceback id = self._next_resource_id = self._next_resource_id + 1 print('+{0} ACQUIRE {1}'.format(id, self.__class__.__name__)) r = self._orig_acquire(*args, **kwargs) r._resource_id = id print('-{0} ACQUIRE {1}'.format(id, self.__class__.__name__)) if not hasattr(r, 'acquired_by'): r.acquired_by = [] r.acquired_by.append(traceback.format_stack()) return r def release(self, resource): # noqa id = resource._resource_id print('+{0} RELEASE {1}'.format(id, self.__class__.__name__)) r = self._orig_release(resource) print('-{0} RELEASE {1}'.format(id, self.__class__.__name__)) self._next_resource_id -= 1 return r class ConnectionPool(Resource): LimitExceeded = exceptions.ConnectionLimitExceeded def __init__(self, connection, limit=None, preload=None): self.connection = connection super(ConnectionPool, self).__init__(limit=limit, preload=preload) def new(self): return self.connection.clone() def release_resource(self, resource): try: resource._debug('released') except AttributeError: pass def close_resource(self, resource): resource._close() def collect_resource(self, resource, socket_timeout=0.1): return resource.collect(socket_timeout) @contextmanager def acquire_channel(self, block=False): with self.acquire(block=block) as connection: yield connection, connection.default_channel def setup(self): if self.limit: for i in range(self.limit): if i < self.preload: conn = self.new() conn.connect() else: conn = lazy(self.new) self._resource.put_nowait(conn) def prepare(self, resource): if callable(resource): resource = resource() resource._debug('acquired') return resource class ChannelPool(Resource): LimitExceeded = exceptions.ChannelLimitExceeded def __init__(self, connection, limit=None, preload=None): self.connection = connection super(ChannelPool, self).__init__(limit=limit, preload=preload) def new(self): return lazy(self.connection.channel) def setup(self): channel = self.new() if self.limit: for i in range(self.limit): self._resource.put_nowait( i < self.preload and channel() or lazy(channel)) def prepare(self, channel): if callable(channel): channel = channel() return channel def maybe_channel(channel): """Return the default channel if argument is a connection instance, otherwise just return the channel given.""" if isinstance(channel, Connection): return channel.default_channel return channel def is_connection(obj): return isinstance(obj, Connection)