def __init__(self, close_callback=None):
"""
Initializes a BaseChannel instance.
@param transport Underlying transport used for broker communication. Can be None, if so, will
use the AMQPTransport stateless singleton.
@type transport BaseTransport
@param close_callback The method to invoke when close() is called on this BaseChannel. May be left as None,
in which case close_impl() will be called. This expects to be a callable taking one
param, this channel instance.
"""
self.set_close_callback(close_callback)
self._transport = None
# setup FSM for BaseChannel / SendChannel tree
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_ATTACH, self.S_INIT, None,
self.S_ACTIVE)
self._fsm.add_transition(self.I_CLOSE, self.S_ACTIVE, self._on_close,
self.S_CLOSED)
self._fsm.add_transition(
self.I_CLOSE, self.S_CLOSED,
lambda *args: self.on_channel_close(None, 0, ""),
self.S_CLOSED) # closed is a goal state, multiple closes are ok
self._fsm.add_transition(self.I_CLOSE, self.S_INIT, None,
self.S_CLOSED) # INIT to CLOSED is fine too
def on_start(self):
self.queue_name = self.CFG.get_safe('process.queue_name', self.id)
self.subscriber = StreamSubscriber(process=self,
exchange_name=self.queue_name,
callback=self.recv_packet)
self._msg_buffer = []
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_READY, self.S_INIT, None, self.S_READY)
self._fsm.add_transition(self.I_FETCH, self.S_READY, None,
self.S_FETCH)
self._fsm.add_transition(self.I_READY, self.S_FETCH, self._reset,
self.S_READY)
self._fsm.add_transition(self.I_EXCEPTION, self.S_FETCH, None,
self.S_EXCEPTION)
self._fsm.add_transition(self.I_READY, self.S_EXCEPTION, self._reset,
self.S_READY)
self.subscriber.initialize()
self.done = gevent.event.Event()
self._fsm.process(self.I_READY)
self.greenlet = gevent.spawn(self.activate)
def on_start(self):
self.queue_name = self.CFG.get_safe('process.queue_name', self.id)
self.subscriber = StreamSubscriber(process=self, exchange_name=self.queue_name, callback=self.recv_packet)
self._msg_buffer = []
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_READY, self.S_INIT, None, self.S_READY)
self._fsm.add_transition(self.I_FETCH, self.S_READY, None, self.S_FETCH)
self._fsm.add_transition(self.I_READY, self.S_FETCH, self._reset, self.S_READY)
self._fsm.add_transition(self.I_EXCEPTION, self.S_FETCH, None, self.S_EXCEPTION)
self._fsm.add_transition(self.I_READY, self.S_EXCEPTION, self._reset, self.S_READY)
self.subscriber.initialize()
self.done = gevent.event.Event()
self._fsm.process(self.I_READY)
self.greenlet = gevent.spawn(self.activate)
def __init__(self, transport=None, close_callback=None):
"""
Initializes a BaseChannel instance.
@param transport Underlying transport used for broker communication. Can be None, if so, will
use the AMQPTransport stateless singleton.
@type transport BaseTransport
@param close_callback The method to invoke when close() is called on this BaseChannel. May be left as None,
in which case close_impl() will be called. This expects to be a callable taking one
param, this channel instance.
"""
self.set_close_callback(close_callback)
self._transport = transport or AMQPTransport.get_instance()
# setup FSM for BaseChannel / SendChannel tree
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_ATTACH, self.S_INIT, None, self.S_ACTIVE)
self._fsm.add_transition(self.I_CLOSE, self.S_ACTIVE, self._on_close, self.S_CLOSED)
self._fsm.add_transition(self.I_CLOSE, self.S_CLOSED, None, self.S_CLOSED) # closed is a goal state, multiple closes are ok and are no-ops
self._fsm.add_transition(self.I_CLOSE, self.S_INIT, None, self.S_CLOSED) # INIT to CLOSED is fine too
class BaseChannel(object):
_close_callback = None # close callback to use when closing, not always set (used for pooling)
_closed_error_callback = None # callback which triggers when the underlying transport closes with error
_exchange = None # exchange (too AMQP specific)
_close_event = None # used for giving notice a close was processed
# exchange related settings @TODO: these should likely come from config instead
_exchange_type = 'topic'
_exchange_auto_delete = None
_exchange_durable = None
# States, Inputs for FSM
S_INIT = 'INIT'
S_ACTIVE = 'ACTIVE'
S_CLOSED = 'CLOSED'
I_ATTACH = 'ATTACH'
I_CLOSE = 'CLOSE'
def __init__(self, close_callback=None):
"""
Initializes a BaseChannel instance.
@param transport Underlying transport used for broker communication. Can be None, if so, will
use the AMQPTransport stateless singleton.
@type transport BaseTransport
@param close_callback The method to invoke when close() is called on this BaseChannel. May be left as None,
in which case close_impl() will be called. This expects to be a callable taking one
param, this channel instance.
"""
self.set_close_callback(close_callback)
self._transport = None
# setup FSM for BaseChannel / SendChannel tree
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_ATTACH, self.S_INIT, None,
self.S_ACTIVE)
self._fsm.add_transition(self.I_CLOSE, self.S_ACTIVE, self._on_close,
self.S_CLOSED)
self._fsm.add_transition(
self.I_CLOSE, self.S_CLOSED,
lambda *args: self.on_channel_close(None, 0, ""),
self.S_CLOSED) # closed is a goal state, multiple closes are ok
self._fsm.add_transition(self.I_CLOSE, self.S_INIT, None,
self.S_CLOSED) # INIT to CLOSED is fine too
@property
def exchange_auto_delete(self):
if self._exchange_auto_delete is not None:
return self._exchange_auto_delete
if hasattr(self, '_send_name') and hasattr(self._send_name,
'exchange_auto_delete'):
return self._send_name.exchange_auto_delete
if hasattr(self, '_recv_name') and hasattr(self._recv_name,
'exchange_auto_delete'):
return self._recv_name.exchange_auto_delete
return True
@exchange_auto_delete.setter
def exchange_auto_delete(self, value):
self._exchange_auto_delete = value
@property
def exchange_durable(self):
if self._exchange_durable is not None:
return self._exchange_durable
if hasattr(self, '_send_name') and hasattr(self._send_name,
'exchange_durable'):
return self._send_name.exchange_durable
if hasattr(self, '_recv_name') and hasattr(self._recv_name,
'exchange_durable'):
return self._recv_name.exchange_durable
return False
@exchange_durable.setter
def exchange_durable(self, value):
self._exchange_durable = value
def set_close_callback(self, close_callback):
"""
Sets a callback method to be called when this channel's close method is invoked.
By default, if no callback is set on this channel, close_impl() is called instead.
The close callback is chiefly used to pool channels in the Node.
@param close_callback The callback method. Should be a callable taking one argument, this channel.
"""
self._close_callback = close_callback
@contextmanager
def _ensure_transport(self):
"""
Ensures this Channel has been activated with the Node.
"""
# log.debug("BaseChannel._ensure_transport (current: %s)", self._transport is not None)
if not self._transport:
raise ChannelError("No transport attached")
if not self._lock:
raise ChannelError("No lock available")
# is lock already acquired? spit out a notice
if self._lock._is_owned():
log.warn(
"INTERLEAVE DETECTED:\n\nCURRENT STACK:\n%s\n\nSTACK THAT LOCKED: %s\n",
"".join(traceback.format_stack()), "".join(self._lock_trace))
with self._lock:
# we could wait and wait, and it gets closed, and unless we check again, we'd never know!
if not self._transport:
raise ChannelError("No transport attached")
self._lock_trace = traceback.format_stack()
try:
yield
finally:
self._lock_trace = None
def _declare_exchange(self, exchange):
"""
Performs an AMQP exchange declare.
@param exchange The name of the exchange to use.
@TODO: this really shouldn't exist, messaging layer should not make this declaration. it will be provided.
perhaps push into an ion layer derivation to help bootstrapping / getting started fast.
"""
self._exchange = exchange
assert self._exchange
assert self._transport
with self._ensure_transport():
# log.debug("Exchange declare: %s, TYPE %s, DUR %s AD %s", self._exchange, self._exchange_type,
# self.exchange_durable, self.exchange_auto_delete)
self._transport.declare_exchange_impl(
self._exchange,
exchange_type=self._exchange_type,
durable=self.exchange_durable,
auto_delete=self.exchange_auto_delete)
def get_channel_id(self):
"""
Gets the underlying AMQP channel's channel identifier (number).
@return Channel id, or None.
"""
if not self._transport:
return None
return self._transport.channel_number
def reset(self):
"""
Provides a hook for resetting a node (used only by pooling in the node).
At this base level, is a no-op.
"""
pass
def close(self):
"""
Public close method.
If a close callback was specified when creating this instance, it will call that,
otherwise it calls close_impl.
If created via a Node (99% likely), the Node will take care of
calling close_impl for you at the proper time.
@returns An Event you can wait on for completion of the close. Will be set
automatically if the channel came from the Node's pool.
"""
ev = Event()
if self._close_callback:
self._close_callback(self)
ev.set()
else:
self._close_event = ev
self._fsm.process(self.I_CLOSE)
return ev
def _on_close(self, fsm):
self.close_impl()
def close_impl(self):
"""
Closes the AMQP connection.
"""
log.trace("BaseChannel.close_impl (%s)", self.get_channel_id())
if self._transport:
# the close destroys self._transport, so keep a ref here
transport = self._transport
with self._ensure_transport():
transport.close()
# set to None now so nothing else tries to use the channel during the callback
self._transport = None
def on_channel_open(self, transport):
"""
Node calls here to attach a bound transport.
"""
transport.add_on_close_callback(self.on_channel_close)
self.attach_transport(transport)
def attach_transport(self, transport):
"""
Attaches a bound transport and indicates this channel is now open.
"""
self._transport = transport
self._lock = coros.RLock()
self._fsm.process(self.I_ATTACH)
def set_closed_error_callback(self, callback):
"""
Sets the closed error callback.
This callback is called when the underlying transport closes early with an error.
This is typically used for internal operations with the broker and will likely not be
used by others.
@param callback The callback to trigger. Should take three parameters, this channel, the error code, and the error text.
@returns The former value of the closed error callback.
"""
oldval = self._closed_error_callback
self._closed_error_callback = callback
return oldval
@contextmanager
def push_closed_error_callback(self, callback):
"""
Context manager based approach to set_closed_error_callback.
"""
cur_cb = self.set_closed_error_callback(callback)
try:
yield callback
finally:
self.set_closed_error_callback(cur_cb)
def on_channel_close(self, transport, code, text):
"""
Callback for when the Pika channel is closed.
"""
# make callback to user event if we've closed
if self._close_event is not None:
self._close_event.set()
self._close_event = None
# remove transport so we don't try to use it again
# (all?) calls are protected via _ensure_transport, which raise a ChannelError if you try to do anything with it.
self._transport = None
# make callback if it exists!
if not (code == 0 or code == 200) and self._closed_error_callback:
# run in try block because this can shutter the entire connection
try:
self._closed_error_callback(self, code, text)
except Exception, e:
log.warn("Closed error callback caught an exception: %s",
str(e))
# fixup channel state fsm, but only if we're not executing a transition right now
if self._fsm.current_state != self.S_CLOSED and self._fsm.next_state is None:
self._fsm.current_state = self.S_CLOSED
class BaseChannel(object):
_amq_chan = None # underlying transport
_close_callback = None # close callback to use when closing, not always set (used for pooling)
_closed_error_callback = None # callback which triggers when the underlying transport closes with error
_exchange = None # exchange (too AMQP specific)
# exchange related settings @TODO: these should likely come from config instead
_exchange_type = 'topic'
_exchange_auto_delete = True
_exchange_durable = False
# States, Inputs for FSM
S_INIT = 'INIT'
S_ACTIVE = 'ACTIVE'
S_CLOSED = 'CLOSED'
I_ATTACH = 'ATTACH'
I_CLOSE = 'CLOSE'
def __init__(self, transport=None, close_callback=None):
"""
Initializes a BaseChannel instance.
@param transport Underlying transport used for broker communication. Can be None, if so, will
use the AMQPTransport stateless singleton.
@type transport BaseTransport
@param close_callback The method to invoke when close() is called on this BaseChannel. May be left as None,
in which case close_impl() will be called. This expects to be a callable taking one
param, this channel instance.
"""
self.set_close_callback(close_callback)
self._transport = transport or AMQPTransport.get_instance()
# setup FSM for BaseChannel / SendChannel tree
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_ATTACH, self.S_INIT, None, self.S_ACTIVE)
self._fsm.add_transition(self.I_CLOSE, self.S_ACTIVE, self._on_close, self.S_CLOSED)
self._fsm.add_transition(self.I_CLOSE, self.S_CLOSED, None, self.S_CLOSED) # closed is a goal state, multiple closes are ok and are no-ops
self._fsm.add_transition(self.I_CLOSE, self.S_INIT, None, self.S_CLOSED) # INIT to CLOSED is fine too
def set_close_callback(self, close_callback):
"""
Sets a callback method to be called when this channel's close method is invoked.
By default, if no callback is set on this channel, close_impl() is called instead.
The close callback is chiefly used to pool channels in the Node.
@param close_callback The callback method. Should be a callable taking one argument, this channel.
"""
self._close_callback = close_callback
def _ensure_amq_chan(self):
"""
Ensures this Channel has been activated with the Node.
"""
# log.debug("BaseChannel._ensure_amq_chan (current: %s)", self._amq_chan is not None)
if not self._amq_chan:
raise ChannelError("No amq_chan attached")
def _declare_exchange(self, exchange):
"""
Performs an AMQP exchange declare.
@param exchange The name of the exchange to use.
@TODO: this really shouldn't exist, messaging layer should not make this declaration. it will be provided.
perhaps push into an ion layer derivation to help bootstrapping / getting started fast.
"""
self._exchange = exchange
assert self._exchange
self._ensure_amq_chan()
assert self._transport
# log.debug("Exchange declare: %s, TYPE %s, DUR %s AD %s", self._exchange, self._exchange_type,
# self._exchange_durable, self._exchange_auto_delete)
self._transport.declare_exchange_impl(self._amq_chan,
self._exchange,
exchange_type=self._exchange_type,
durable=self._exchange_durable,
auto_delete=self._exchange_auto_delete)
def attach_underlying_channel(self, amq_chan):
"""
Attaches an AMQP channel and indicates this channel is now open.
"""
self._amq_chan = amq_chan
self._fsm.process(self.I_ATTACH)
def get_channel_id(self):
"""
Gets the underlying AMQP channel's channel identifier (number).
@return Channel id, or None.
"""
if not self._amq_chan:
return None
return self._amq_chan.channel_number
def reset(self):
"""
Provides a hook for resetting a node (used only by pooling in the node).
At this base level, is a no-op.
"""
pass
def close(self):
"""
Public close method.
If a close callback was specified when creating this instance, it will call that,
otherwise it calls close_impl.
If created via a Node (99% likely), the Node will take care of
calling close_impl for you at the proper time.
"""
if self._close_callback:
self._close_callback(self)
else:
self._fsm.process(self.I_CLOSE)
def _on_close(self, fsm):
self.close_impl()
def close_impl(self):
"""
Closes the AMQP connection.
"""
log.debug("BaseChannel.close_impl (%s)", self.get_channel_id())
if self._amq_chan:
# the close destroys self._amq_chan, so keep a ref here
amq_chan = self._amq_chan
amq_chan.close()
# set to None now so nothing else tries to use the channel during the callback
self._amq_chan = None
# PIKA BUG: in v0.9.5, this amq_chan instance will be left around in the callbacks
# manager, and trips a bug in the handler for on_basic_deliver. We attempt to clean
# up for Pika here so we don't goof up when reusing a channel number.
amq_chan.callbacks.remove(amq_chan.channel_number, 'Basic.GetEmpty')
amq_chan.callbacks.remove(amq_chan.channel_number, 'Channel.Close')
amq_chan.callbacks.remove(amq_chan.channel_number, '_on_basic_deliver')
amq_chan.callbacks.remove(amq_chan.channel_number, '_on_basic_get')
# uncomment these lines to see the full callback list that Pika maintains
#stro = pprint.pformat(callbacks._callbacks)
#log.error(str(stro))
def on_channel_open(self, amq_chan):
"""
The node calls here to attach an open Pika channel.
We attach our on_channel_close handler and then call attach_underlying_channel.
"""
amq_chan.add_on_close_callback(self.on_channel_close)
self.attach_underlying_channel(amq_chan)
def set_closed_error_callback(self, callback):
"""
Sets the closed error callback.
This callback is called when the underlying transport closes early with an error.
This is typically used for internal operations with the broker and will likely not be
used by others.
@param callback The callback to trigger. Should take three parameters, this channel, the error code, and the error text.
@returns The former value of the closed error callback.
"""
oldval = self._closed_error_callback
self._closed_error_callback = callback
return oldval
@contextmanager
def push_closed_error_callback(self, callback):
"""
Context manager based approach to set_closed_error_callback.
"""
cur_cb = self.set_closed_error_callback(callback)
try:
yield callback
finally:
self.set_closed_error_callback(cur_cb)
def on_channel_close(self, code, text):
"""
Callback for when the Pika channel is closed.
"""
logmeth = log.debug
if not (code == 0 or code == 200):
logmeth = log.error
logmeth("BaseChannel.on_channel_close\n\tchannel number: %s\n\tcode: %d\n\ttext: %s", self.get_channel_id(), code, text)
# remove amq_chan so we don't try to use it again
# (all?) calls are protected via _ensure_amq_chan, which raise a ChannelError if you try to do anything with it.
self._amq_chan = None
# make callback if it exists!
if not (code == 0 or code == 200) and self._closed_error_callback:
# run in try block because this can shutter the entire connection
try:
self._closed_error_callback(self, code, text)
except Exception, e:
log.warn("Closed error callback caught an exception: %s", str(e))
class BaseChannel(object):
_amq_chan = None # underlying transport
_close_callback = None # close callback to use when closing, not always set (used for pooling)
_closed_error_callback = None # callback which triggers when the underlying transport closes with error
_exchange = None # exchange (too AMQP specific)
# exchange related settings @TODO: these should likely come from config instead
_exchange_type = 'topic'
_exchange_auto_delete = True
_exchange_durable = False
# States, Inputs for FSM
S_INIT = 'INIT'
S_ACTIVE = 'ACTIVE'
S_CLOSED = 'CLOSED'
I_ATTACH = 'ATTACH'
I_CLOSE = 'CLOSE'
def __init__(self, transport=None, close_callback=None):
"""
Initializes a BaseChannel instance.
@param transport Underlying transport used for broker communication. Can be None, if so, will
use the AMQPTransport stateless singleton.
@type transport BaseTransport
@param close_callback The method to invoke when close() is called on this BaseChannel. May be left as None,
in which case close_impl() will be called. This expects to be a callable taking one
param, this channel instance.
"""
self.set_close_callback(close_callback)
self._transport = transport or AMQPTransport.get_instance()
# setup FSM for BaseChannel / SendChannel tree
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_ATTACH, self.S_INIT, None,
self.S_ACTIVE)
self._fsm.add_transition(self.I_CLOSE, self.S_ACTIVE, self._on_close,
self.S_CLOSED)
self._fsm.add_transition(
self.I_CLOSE, self.S_CLOSED, None, self.S_CLOSED
) # closed is a goal state, multiple closes are ok and are no-ops
self._fsm.add_transition(self.I_CLOSE, self.S_INIT, None,
self.S_CLOSED) # INIT to CLOSED is fine too
def set_close_callback(self, close_callback):
"""
Sets a callback method to be called when this channel's close method is invoked.
By default, if no callback is set on this channel, close_impl() is called instead.
The close callback is chiefly used to pool channels in the Node.
@param close_callback The callback method. Should be a callable taking one argument, this channel.
"""
self._close_callback = close_callback
def _ensure_amq_chan(self):
"""
Ensures this Channel has been activated with the Node.
"""
# log.debug("BaseChannel._ensure_amq_chan (current: %s)", self._amq_chan is not None)
if not self._amq_chan:
raise ChannelError("No amq_chan attached")
def _declare_exchange(self, exchange):
"""
Performs an AMQP exchange declare.
@param exchange The name of the exchange to use.
@TODO: this really shouldn't exist, messaging layer should not make this declaration. it will be provided.
perhaps push into an ion layer derivation to help bootstrapping / getting started fast.
"""
self._exchange = exchange
assert self._exchange
self._ensure_amq_chan()
assert self._transport
# log.debug("Exchange declare: %s, TYPE %s, DUR %s AD %s", self._exchange, self._exchange_type,
# self._exchange_durable, self._exchange_auto_delete)
self._transport.declare_exchange_impl(
self._amq_chan,
self._exchange,
exchange_type=self._exchange_type,
durable=self._exchange_durable,
auto_delete=self._exchange_auto_delete)
def attach_underlying_channel(self, amq_chan):
"""
Attaches an AMQP channel and indicates this channel is now open.
"""
self._amq_chan = amq_chan
self._fsm.process(self.I_ATTACH)
def get_channel_id(self):
"""
Gets the underlying AMQP channel's channel identifier (number).
@return Channel id, or None.
"""
if not self._amq_chan:
return None
return self._amq_chan.channel_number
def reset(self):
"""
Provides a hook for resetting a node (used only by pooling in the node).
At this base level, is a no-op.
"""
pass
def close(self):
"""
Public close method.
If a close callback was specified when creating this instance, it will call that,
otherwise it calls close_impl.
If created via a Node (99% likely), the Node will take care of
calling close_impl for you at the proper time.
"""
if self._close_callback:
self._close_callback(self)
else:
self._fsm.process(self.I_CLOSE)
def _on_close(self, fsm):
self.close_impl()
def close_impl(self):
"""
Closes the AMQP connection.
"""
log.debug("BaseChannel.close_impl (%s)", self.get_channel_id())
if self._amq_chan:
# the close destroys self._amq_chan, so keep a ref here
amq_chan = self._amq_chan
amq_chan.close()
# set to None now so nothing else tries to use the channel during the callback
self._amq_chan = None
# PIKA BUG: in v0.9.5, this amq_chan instance will be left around in the callbacks
# manager, and trips a bug in the handler for on_basic_deliver. We attempt to clean
# up for Pika here so we don't goof up when reusing a channel number.
amq_chan.callbacks.remove(amq_chan.channel_number,
'Basic.GetEmpty')
amq_chan.callbacks.remove(amq_chan.channel_number, 'Channel.Close')
amq_chan.callbacks.remove(amq_chan.channel_number,
'_on_basic_deliver')
amq_chan.callbacks.remove(amq_chan.channel_number, '_on_basic_get')
# uncomment these lines to see the full callback list that Pika maintains
#stro = pprint.pformat(callbacks._callbacks)
#log.error(str(stro))
def on_channel_open(self, amq_chan):
"""
The node calls here to attach an open Pika channel.
We attach our on_channel_close handler and then call attach_underlying_channel.
"""
amq_chan.add_on_close_callback(self.on_channel_close)
self.attach_underlying_channel(amq_chan)
def set_closed_error_callback(self, callback):
"""
Sets the closed error callback.
This callback is called when the underlying transport closes early with an error.
This is typically used for internal operations with the broker and will likely not be
used by others.
@param callback The callback to trigger. Should take three parameters, this channel, the error code, and the error text.
@returns The former value of the closed error callback.
"""
oldval = self._closed_error_callback
self._closed_error_callback = callback
return oldval
@contextmanager
def push_closed_error_callback(self, callback):
"""
Context manager based approach to set_closed_error_callback.
"""
cur_cb = self.set_closed_error_callback(callback)
try:
yield callback
finally:
self.set_closed_error_callback(cur_cb)
def on_channel_close(self, code, text):
"""
Callback for when the Pika channel is closed.
"""
logmeth = log.debug
if not (code == 0 or code == 200):
logmeth = log.error
logmeth(
"BaseChannel.on_channel_close\n\tchannel number: %s\n\tcode: %d\n\ttext: %s",
self.get_channel_id(), code, text)
# remove amq_chan so we don't try to use it again
# (all?) calls are protected via _ensure_amq_chan, which raise a ChannelError if you try to do anything with it.
self._amq_chan = None
# make callback if it exists!
if not (code == 0 or code == 200) and self._closed_error_callback:
# run in try block because this can shutter the entire connection
try:
self._closed_error_callback(self, code, text)
except Exception, e:
log.warn("Closed error callback caught an exception: %s",
str(e))
class BaseChannel(object):
_close_callback = None # close callback to use when closing, not always set (used for pooling)
_closed_error_callback = None # callback which triggers when the underlying transport closes with error
_exchange = None # exchange (too AMQP specific)
_close_event = None # used for giving notice a close was processed
# exchange related settings @TODO: these should likely come from config instead
_exchange_type = 'topic'
_exchange_auto_delete = None
_exchange_durable = None
# States, Inputs for FSM
S_INIT = 'INIT'
S_ACTIVE = 'ACTIVE'
S_CLOSED = 'CLOSED'
I_ATTACH = 'ATTACH'
I_CLOSE = 'CLOSE'
def __init__(self, close_callback=None):
"""
Initializes a BaseChannel instance.
@param transport Underlying transport used for broker communication. Can be None, if so, will
use the AMQPTransport stateless singleton.
@type transport BaseTransport
@param close_callback The method to invoke when close() is called on this BaseChannel. May be left as None,
in which case close_impl() will be called. This expects to be a callable taking one
param, this channel instance.
"""
self.set_close_callback(close_callback)
self._transport = None
# setup FSM for BaseChannel / SendChannel tree
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_ATTACH, self.S_INIT, None, self.S_ACTIVE)
self._fsm.add_transition(self.I_CLOSE, self.S_ACTIVE, self._on_close, self.S_CLOSED)
self._fsm.add_transition(self.I_CLOSE, self.S_CLOSED, lambda *args: self.on_channel_close(None, 0, ""), self.S_CLOSED) # closed is a goal state, multiple closes are ok
self._fsm.add_transition(self.I_CLOSE, self.S_INIT, None, self.S_CLOSED) # INIT to CLOSED is fine too
@property
def exchange_auto_delete(self):
# Fix OOIION-1710: Added because exchanges get deleted on broker restart
if CFG.get_safe('container.messaging.names.durable', False):
self._exchange_auto_delete = False
return False
if self._exchange_auto_delete is not None:
return self._exchange_auto_delete
if hasattr(self, '_send_name') and hasattr(self._send_name, 'exchange_auto_delete'):
return self._send_name.exchange_auto_delete
if hasattr(self, '_recv_name') and hasattr(self._recv_name, 'exchange_auto_delete'):
return self._recv_name.exchange_auto_delete
return True
@exchange_auto_delete.setter
def exchange_auto_delete(self, value):
self._exchange_auto_delete = value
@property
def exchange_durable(self):
# Fix OOIION-1710: Added because exchanges get deleted on broker restart
if CFG.get_safe('container.messaging.names.durable', False):
self._exchange_durable = True
return True
if self._exchange_durable is not None:
return self._exchange_durable
if hasattr(self, '_send_name') and hasattr(self._send_name, 'exchange_durable'):
return self._send_name.exchange_durable
if hasattr(self, '_recv_name') and hasattr(self._recv_name, 'exchange_durable'):
return self._recv_name.exchange_durable
return False
@exchange_durable.setter
def exchange_durable(self, value):
self._exchange_durable = value
def set_close_callback(self, close_callback):
"""
Sets a callback method to be called when this channel's close method is invoked.
By default, if no callback is set on this channel, close_impl() is called instead.
The close callback is chiefly used to pool channels in the Node.
@param close_callback The callback method. Should be a callable taking one argument, this channel.
"""
self._close_callback = close_callback
@contextmanager
def _ensure_transport(self):
"""
Ensures this Channel has been activated with the Node.
"""
# log.debug("BaseChannel._ensure_transport (current: %s)", self._transport is not None)
if not self._transport:
raise ChannelError("No transport attached")
if not self._lock:
raise ChannelError("No lock available")
# is lock already acquired? spit out a notice
if self._lock._is_owned():
log.warn("INTERLEAVE DETECTED:\n\nCURRENT STACK:\n%s\n\nSTACK THAT LOCKED: %s\n",
"".join(traceback.format_stack()), "".join(self._lock_trace))
with self._lock:
# we could wait and wait, and it gets closed, and unless we check again, we'd never know!
if not self._transport:
raise ChannelError("No transport attached")
self._lock_trace = traceback.format_stack()
try:
yield
finally:
self._lock_trace = None
def _declare_exchange(self, exchange):
"""
Performs an AMQP exchange declare.
@param exchange The name of the exchange to use.
@TODO: this really shouldn't exist, messaging layer should not make this declaration. it will be provided.
perhaps push into an ion layer derivation to help bootstrapping / getting started fast.
"""
self._exchange = exchange
assert self._exchange
assert self._transport
with self._ensure_transport():
# log.debug("Exchange declare: %s, TYPE %s, DUR %s AD %s", self._exchange, self._exchange_type,
# self.exchange_durable, self.exchange_auto_delete)
self._transport.declare_exchange_impl(self._exchange,
exchange_type=self._exchange_type,
durable=self.exchange_durable,
auto_delete=self.exchange_auto_delete)
def get_channel_id(self):
"""
Gets the underlying AMQP channel's channel identifier (number).
@return Channel id, or None.
"""
if not self._transport:
return None
return self._transport.channel_number
def reset(self):
"""
Provides a hook for resetting a node (used only by pooling in the node).
At this base level, is a no-op.
"""
pass
def close(self):
"""
Public close method.
If a close callback was specified when creating this instance, it will call that,
otherwise it calls close_impl.
If created via a Node (99% likely), the Node will take care of
calling close_impl for you at the proper time.
@returns An Event you can wait on for completion of the close. Will be set
automatically if the channel came from the Node's pool.
"""
ev = Event()
if self._close_callback:
self._close_callback(self)
ev.set()
else:
self._close_event = ev
self._fsm.process(self.I_CLOSE)
return ev
def _on_close(self, fsm):
self.close_impl()
def close_impl(self):
"""
Closes the AMQP connection.
"""
#log.trace("BaseChannel.close_impl (%s)", self.get_channel_id())
if self._transport:
# the close destroys self._transport, so keep a ref here
transport = self._transport
with self._ensure_transport():
transport.close()
# set to None now so nothing else tries to use the channel during the callback
self._transport = None
def on_channel_open(self, transport):
"""
Node calls here to attach a bound transport.
"""
transport.add_on_close_callback(self.on_channel_close)
self.attach_transport(transport)
def attach_transport(self, transport):
"""
Attaches a bound transport and indicates this channel is now open.
"""
self._transport = transport
self._lock = RLock()
self._fsm.process(self.I_ATTACH)
def set_closed_error_callback(self, callback):
"""
Sets the closed error callback.
This callback is called when the underlying transport closes early with an error.
This is typically used for internal operations with the broker and will likely not be
used by others.
@param callback The callback to trigger. Should take three parameters, this channel, the error code, and the error text.
@returns The former value of the closed error callback.
"""
oldval = self._closed_error_callback
self._closed_error_callback = callback
return oldval
@contextmanager
def push_closed_error_callback(self, callback):
"""
Context manager based approach to set_closed_error_callback.
"""
cur_cb = self.set_closed_error_callback(callback)
try:
yield callback
finally:
self.set_closed_error_callback(cur_cb)
def on_channel_close(self, transport, code, text):
"""
Callback for when the Pika channel is closed.
"""
# make callback to user event if we've closed
if self._close_event is not None:
self._close_event.set()
self._close_event = None
# remove transport so we don't try to use it again
# (all?) calls are protected via _ensure_transport, which raise a ChannelError if you try to do anything with it.
self._transport = None
# make callback if it exists!
if not (code == 0 or code == 200) and self._closed_error_callback:
# run in try block because this can shutter the entire connection
try:
self._closed_error_callback(self, code, text)
except Exception as e:
log.warn("Closed error callback caught an exception: %s", str(e))
# fixup channel state fsm, but only if we're not executing a transition right now
if self._fsm.current_state != self.S_CLOSED and self._fsm.next_state is None:
self._fsm.current_state = self.S_CLOSED
class TransformPoll(TransformStreamListener):
'''
Transform Extension of Stream Listener which allows the transform to poll
and buffer data from the queue, in lieu of consuming automatically.
'''
MESSAGE_BUFFER = 1024
TIMEOUT = 2.0
S_INIT = 'INIT'
S_READY = 'READY'
S_FETCH = 'FETCHED'
S_EXCEPTION = 'EXCEPTION'
I_READY = 'RESET'
I_FETCH = 'FETCH'
I_EXCEPTION = 'EXCEPT'
def on_start(self):
self.queue_name = self.CFG.get_safe('process.queue_name', self.id)
self.subscriber = StreamSubscriber(process=self, exchange_name=self.queue_name, callback=self.recv_packet)
self._msg_buffer = []
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_READY, self.S_INIT, None, self.S_READY)
self._fsm.add_transition(self.I_FETCH, self.S_READY, None, self.S_FETCH)
self._fsm.add_transition(self.I_READY, self.S_FETCH, self._reset, self.S_READY)
self._fsm.add_transition(self.I_EXCEPTION, self.S_FETCH, None, self.S_EXCEPTION)
self._fsm.add_transition(self.I_READY, self.S_EXCEPTION, self._reset, self.S_READY)
self.subscriber.initialize()
self.done = gevent.event.Event()
self._fsm.process(self.I_READY)
self.greenlet = gevent.spawn(self.activate)
def on_quit(self):
self._ack_all()
self.subscriber.close()
if self.subscriber._chan._amq_chan is not None:
log.error('Channel is still attached, forcing closure.')
self.subscriber._chan.close_impl()
self.done.set()
self.greenlet.join(5)
self.greenlet = None
def _reset(self, fsm):
self._ack_all()
def _ack_all(self):
while self._msg_buffer:
msg = self._msg_buffer.pop()
try:
msg.ack()
except:
log.critical('Failed to ack message')
def ack_all(self):
'''
Acknowledge all the messages in the current buffer.
'''
self._fsm.process(self.I_READY)
def reject_all(self):
'''
Reject all the messages in the curernt buffer.
'''
self._reject_all()
self._fsm.process(self.I_READY)
def _reject_all(self):
while self._msg_buffer:
msg = self._msg_buffer.pop()
try:
msg.reject()
except:
log.critical('Failed to reject message')
def poll_trigger(self):
'''
Conditional method for determining when to fetch, meant to be overridden.
'''
n = self.poll()
if n:
return True
else:
return False
def poll(self):
'''
Returns the number of available messages
'''
return self.subscriber.get_stats()[0]
def fetch(self):
'''
Method for fetching
'''
n = self.poll()
return self._fetch(n)
def _fetch(self, n):
'''
Fetches n messages from the queue,
The messages must be acknowledged before another fetch can take place
'''
self._fsm.process(self.I_FETCH)
try:
if len(self._msg_buffer) + n >= self.MESSAGE_BUFFER:
raise BadRequest('Request exceeds maximum buffer space')
try:
self._msg_buffer.extend( self.subscriber.get_n_msgs(n, self.TIMEOUT))
except gevent.Timeout:
raise Timeout
except:
self._fsm.process(self.I_EXCEPTION)
return []
return [(msg.body, msg.headers) for msg in self._msg_buffer]
def activate(self):
pass
class TransformPoll(TransformStreamListener):
'''
Transform Extension of Stream Listener which allows the transform to poll
and buffer data from the queue, in lieu of consuming automatically.
'''
MESSAGE_BUFFER = 1024
TIMEOUT = 2.0
S_INIT = 'INIT'
S_READY = 'READY'
S_FETCH = 'FETCHED'
S_EXCEPTION = 'EXCEPTION'
I_READY = 'RESET'
I_FETCH = 'FETCH'
I_EXCEPTION = 'EXCEPT'
def on_start(self):
self.queue_name = self.CFG.get_safe('process.queue_name', self.id)
self.subscriber = StreamSubscriber(process=self,
exchange_name=self.queue_name,
callback=self.recv_packet)
self._msg_buffer = []
self._fsm = FSM(self.S_INIT)
self._fsm.add_transition(self.I_READY, self.S_INIT, None, self.S_READY)
self._fsm.add_transition(self.I_FETCH, self.S_READY, None,
self.S_FETCH)
self._fsm.add_transition(self.I_READY, self.S_FETCH, self._reset,
self.S_READY)
self._fsm.add_transition(self.I_EXCEPTION, self.S_FETCH, None,
self.S_EXCEPTION)
self._fsm.add_transition(self.I_READY, self.S_EXCEPTION, self._reset,
self.S_READY)
self.subscriber.initialize()
self.done = gevent.event.Event()
self._fsm.process(self.I_READY)
self.greenlet = gevent.spawn(self.activate)
def on_quit(self):
self._ack_all()
self.subscriber.close()
if self.subscriber._chan._amq_chan is not None:
log.error('Channel is still attached, forcing closure.')
self.subscriber._chan.close_impl()
self.done.set()
self.greenlet.join(5)
self.greenlet = None
def _reset(self, fsm):
self._ack_all()
def _ack_all(self):
while self._msg_buffer:
msg = self._msg_buffer.pop()
try:
msg.ack()
except:
log.critical('Failed to ack message')
def ack_all(self):
'''
Acknowledge all the messages in the current buffer.
'''
self._fsm.process(self.I_READY)
def reject_all(self):
'''
Reject all the messages in the curernt buffer.
'''
self._reject_all()
self._fsm.process(self.I_READY)
def _reject_all(self):
while self._msg_buffer:
msg = self._msg_buffer.pop()
try:
msg.reject()
except:
log.critical('Failed to reject message')
def poll_trigger(self):
'''
Conditional method for determining when to fetch, meant to be overridden.
'''
n = self.poll()
if n:
return True
else:
return False
def poll(self):
'''
Returns the number of available messages
'''
return self.subscriber.get_stats()[0]
def fetch(self):
'''
Method for fetching
'''
n = self.poll()
return self._fetch(n)
def _fetch(self, n):
'''
Fetches n messages from the queue,
The messages must be acknowledged before another fetch can take place
'''
self._fsm.process(self.I_FETCH)
try:
if len(self._msg_buffer) + n >= self.MESSAGE_BUFFER:
raise BadRequest('Request exceeds maximum buffer space')
try:
self._msg_buffer.extend(
self.subscriber.get_n_msgs(n, self.TIMEOUT))
except gevent.Timeout:
raise Timeout
except:
self._fsm.process(self.I_EXCEPTION)
return []
return [(msg.body, msg.headers) for msg in self._msg_buffer]
def activate(self):
pass