This document describes the current stable version of Celery (3.1). For development docs, go here.
Source code for kombu.connection
"""
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 "<stdin>", line 1, in <module>
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 "<stdin>", line 1, in <module>
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 '<Connection: {0} at 0x{1:x}>'.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)
