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# Copyright 2015, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""State and behavior for ingestion during an operation."""
import abc
import collections
import enum
import six
from grpc.framework.core import _constants
from grpc.framework.core import _interfaces
from grpc.framework.core import _utilities
from grpc.framework.foundation import abandonment
from grpc.framework.foundation import callable_util
from grpc.framework.interfaces.base import base
_CREATE_SUBSCRIPTION_EXCEPTION_LOG_MESSAGE = 'Exception initializing ingestion!'
_INGESTION_EXCEPTION_LOG_MESSAGE = 'Exception during ingestion!'
class _SubscriptionCreation(
collections.namedtuple(
'_SubscriptionCreation',
('kind', 'subscription', 'code', 'details',))):
"""A sum type for the outcome of ingestion initialization.
Attributes:
kind: A Kind value coarsely indicating how subscription creation completed.
subscription: The created subscription. Only present if kind is
Kind.SUBSCRIPTION.
code: A code value to be sent to the other side of the operation along with
an indication that the operation is being aborted due to an error on the
remote side of the operation. Only present if kind is Kind.REMOTE_ERROR.
details: A details value to be sent to the other side of the operation
along with an indication that the operation is being aborted due to an
error on the remote side of the operation. Only present if kind is
Kind.REMOTE_ERROR.
"""
@enum.unique
class Kind(enum.Enum):
SUBSCRIPTION = 'subscription'
REMOTE_ERROR = 'remote error'
ABANDONED = 'abandoned'
class _SubscriptionCreator(six.with_metaclass(abc.ABCMeta)):
"""Common specification of subscription-creating behavior."""
@abc.abstractmethod
def create(self, group, method):
"""Creates the base.Subscription of the local customer.
Any exceptions raised by this method should be attributed to and treated as
defects in the customer code called by this method.
Args:
group: The group identifier of the operation.
method: The method identifier of the operation.
Returns:
A _SubscriptionCreation describing the result of subscription creation.
"""
raise NotImplementedError()
class _ServiceSubscriptionCreator(_SubscriptionCreator):
"""A _SubscriptionCreator appropriate for service-side use."""
def __init__(self, servicer, operation_context, output_operator):
"""Constructor.
Args:
servicer: The base.Servicer that will service the operation.
operation_context: A base.OperationContext for the operation to be passed
to the customer.
output_operator: A base.Operator for the operation to be passed to the
customer and to be called by the customer to accept operation data
emitted by the customer.
"""
self._servicer = servicer
self._operation_context = operation_context
self._output_operator = output_operator
def create(self, group, method):
try:
subscription = self._servicer.service(
group, method, self._operation_context, self._output_operator)
except base.NoSuchMethodError as e:
return _SubscriptionCreation(
_SubscriptionCreation.Kind.REMOTE_ERROR, None, e.code, e.details)
except abandonment.Abandoned:
return _SubscriptionCreation(
_SubscriptionCreation.Kind.ABANDONED, None, None, None)
else:
return _SubscriptionCreation(
_SubscriptionCreation.Kind.SUBSCRIPTION, subscription, None, None)
def _wrap(behavior):
def wrapped(*args, **kwargs):
try:
behavior(*args, **kwargs)
except abandonment.Abandoned:
return False
else:
return True
return wrapped
class _IngestionManager(_interfaces.IngestionManager):
"""An implementation of _interfaces.IngestionManager."""
def __init__(
self, lock, pool, subscription, subscription_creator, termination_manager,
transmission_manager, expiration_manager, protocol_manager):
"""Constructor.
Args:
lock: The operation-wide lock.
pool: A thread pool in which to execute customer code.
subscription: A base.Subscription describing the customer's interest in
operation values from the other side. May be None if
subscription_creator is not None.
subscription_creator: A _SubscriptionCreator wrapping the portion of
customer code that when called returns the base.Subscription describing
the customer's interest in operation values from the other side. May be
None if subscription is not None.
termination_manager: The _interfaces.TerminationManager for the operation.
transmission_manager: The _interfaces.TransmissionManager for the
operation.
expiration_manager: The _interfaces.ExpirationManager for the operation.
protocol_manager: The _interfaces.ProtocolManager for the operation.
"""
self._lock = lock
self._pool = pool
self._termination_manager = termination_manager
self._transmission_manager = transmission_manager
self._expiration_manager = expiration_manager
self._protocol_manager = protocol_manager
if subscription is None:
self._subscription_creator = subscription_creator
self._wrapped_operator = None
elif subscription.kind is base.Subscription.Kind.FULL:
self._subscription_creator = None
self._wrapped_operator = _wrap(subscription.operator.advance)
else:
# TODO(nathaniel): Support other subscriptions.
raise ValueError('Unsupported subscription "%s"!' % subscription.kind)
self._pending_initial_metadata = None
self._pending_payloads = []
self._pending_completion = None
self._local_allowance = 1
# A nonnegative integer or None, with None indicating that the local
# customer is done emitting anyway so there's no need to bother it by
# informing it that the remote customer has granted it further permission to
# emit.
self._remote_allowance = 0
self._processing = False
def _abort_internal_only(self):
self._subscription_creator = None
self._wrapped_operator = None
self._pending_initial_metadata = None
self._pending_payloads = None
self._pending_completion = None
def _abort_and_notify(self, outcome_kind, code, details):
self._abort_internal_only()
if self._termination_manager.outcome is None:
outcome = _utilities.Outcome(outcome_kind, code, details)
self._termination_manager.abort(outcome)
self._transmission_manager.abort(outcome)
self._expiration_manager.terminate()
def _operator_next(self):
"""Computes the next step for full-subscription ingestion.
Returns:
An initial_metadata, payload, completion, allowance, continue quintet
indicating what operation values (if any) are available to pass into
customer code and whether or not there is anything immediately
actionable to call customer code to do.
"""
if self._wrapped_operator is None:
return None, None, None, None, False
else:
initial_metadata, payload, completion, allowance, action = [None] * 5
if self._pending_initial_metadata is not None:
initial_metadata = self._pending_initial_metadata
self._pending_initial_metadata = None
action = True
if self._pending_payloads and 0 < self._local_allowance:
payload = self._pending_payloads.pop(0)
self._local_allowance -= 1
action = True
if not self._pending_payloads and self._pending_completion is not None:
completion = self._pending_completion
self._pending_completion = None
action = True
if self._remote_allowance is not None and 0 < self._remote_allowance:
allowance = self._remote_allowance
self._remote_allowance = 0
action = True
return initial_metadata, payload, completion, allowance, bool(action)
def _operator_process(
self, wrapped_operator, initial_metadata, payload,
completion, allowance):
while True:
advance_outcome = callable_util.call_logging_exceptions(
wrapped_operator, _INGESTION_EXCEPTION_LOG_MESSAGE,
initial_metadata=initial_metadata, payload=payload,
completion=completion, allowance=allowance)
if advance_outcome.exception is None:
if advance_outcome.return_value:
with self._lock:
if self._termination_manager.outcome is not None:
return
if completion is not None:
self._termination_manager.ingestion_complete()
initial_metadata, payload, completion, allowance, moar = (
self._operator_next())
if not moar:
self._processing = False
return
else:
with self._lock:
if self._termination_manager.outcome is None:
self._abort_and_notify(
base.Outcome.Kind.LOCAL_FAILURE, None, None)
return
else:
with self._lock:
if self._termination_manager.outcome is None:
self._abort_and_notify(base.Outcome.Kind.LOCAL_FAILURE, None, None)
return
def _operator_post_create(self, subscription):
wrapped_operator = _wrap(subscription.operator.advance)
with self._lock:
if self._termination_manager.outcome is not None:
return
self._wrapped_operator = wrapped_operator
self._subscription_creator = None
metadata, payload, completion, allowance, moar = self._operator_next()
if not moar:
self._processing = False
return
self._operator_process(
wrapped_operator, metadata, payload, completion, allowance)
def _create(self, subscription_creator, group, name):
outcome = callable_util.call_logging_exceptions(
subscription_creator.create,
_CREATE_SUBSCRIPTION_EXCEPTION_LOG_MESSAGE, group, name)
if outcome.return_value is None:
with self._lock:
if self._termination_manager.outcome is None:
self._abort_and_notify(base.Outcome.Kind.LOCAL_FAILURE, None, None)
elif outcome.return_value.kind is _SubscriptionCreation.Kind.ABANDONED:
with self._lock:
if self._termination_manager.outcome is None:
self._abort_and_notify(base.Outcome.Kind.LOCAL_FAILURE, None, None)
elif outcome.return_value.kind is _SubscriptionCreation.Kind.REMOTE_ERROR:
code = outcome.return_value.code
details = outcome.return_value.details
with self._lock:
if self._termination_manager.outcome is None:
self._abort_and_notify(
base.Outcome.Kind.REMOTE_FAILURE, code, details)
elif outcome.return_value.subscription.kind is base.Subscription.Kind.FULL:
self._protocol_manager.set_protocol_receiver(
outcome.return_value.subscription.protocol_receiver)
self._operator_post_create(outcome.return_value.subscription)
else:
# TODO(nathaniel): Support other subscriptions.
raise ValueError(
'Unsupported "%s"!' % outcome.return_value.subscription.kind)
def _store_advance(self, initial_metadata, payload, completion, allowance):
if initial_metadata is not None:
self._pending_initial_metadata = initial_metadata
if payload is not None:
self._pending_payloads.append(payload)
if completion is not None:
self._pending_completion = completion
if allowance is not None and self._remote_allowance is not None:
self._remote_allowance += allowance
def _operator_advance(self, initial_metadata, payload, completion, allowance):
if self._processing:
self._store_advance(initial_metadata, payload, completion, allowance)
else:
action = False
if initial_metadata is not None:
action = True
if payload is not None:
if 0 < self._local_allowance:
self._local_allowance -= 1
action = True
else:
self._pending_payloads.append(payload)
payload = False
if completion is not None:
if self._pending_payloads:
self._pending_completion = completion
else:
action = True
if allowance is not None and self._remote_allowance is not None:
allowance += self._remote_allowance
self._remote_allowance = 0
action = True
if action:
self._pool.submit(
callable_util.with_exceptions_logged(
self._operator_process, _constants.INTERNAL_ERROR_LOG_MESSAGE),
self._wrapped_operator, initial_metadata, payload, completion,
allowance)
def set_group_and_method(self, group, method):
"""See _interfaces.IngestionManager.set_group_and_method for spec."""
if self._subscription_creator is not None and not self._processing:
self._pool.submit(
callable_util.with_exceptions_logged(
self._create, _constants.INTERNAL_ERROR_LOG_MESSAGE),
self._subscription_creator, group, method)
self._processing = True
def add_local_allowance(self, allowance):
"""See _interfaces.IngestionManager.add_local_allowance for spec."""
if any((self._subscription_creator, self._wrapped_operator,)):
self._local_allowance += allowance
if not self._processing:
initial_metadata, payload, completion, allowance, moar = (
self._operator_next())
if moar:
self._pool.submit(
callable_util.with_exceptions_logged(
self._operator_process,
_constants.INTERNAL_ERROR_LOG_MESSAGE),
initial_metadata, payload, completion, allowance)
def local_emissions_done(self):
self._remote_allowance = None
def advance(self, initial_metadata, payload, completion, allowance):
"""See _interfaces.IngestionManager.advance for specification."""
if self._subscription_creator is not None:
self._store_advance(initial_metadata, payload, completion, allowance)
elif self._wrapped_operator is not None:
self._operator_advance(initial_metadata, payload, completion, allowance)
def invocation_ingestion_manager(
subscription, lock, pool, termination_manager, transmission_manager,
expiration_manager, protocol_manager):
"""Creates an IngestionManager appropriate for invocation-side use.
Args:
subscription: A base.Subscription indicating the customer's interest in the
data and results from the service-side of the operation.
lock: The operation-wide lock.
pool: A thread pool in which to execute customer code.
termination_manager: The _interfaces.TerminationManager for the operation.
transmission_manager: The _interfaces.TransmissionManager for the
operation.
expiration_manager: The _interfaces.ExpirationManager for the operation.
protocol_manager: The _interfaces.ProtocolManager for the operation.
Returns:
An IngestionManager appropriate for invocation-side use.
"""
return _IngestionManager(
lock, pool, subscription, None, termination_manager, transmission_manager,
expiration_manager, protocol_manager)
def service_ingestion_manager(
servicer, operation_context, output_operator, lock, pool,
termination_manager, transmission_manager, expiration_manager,
protocol_manager):
"""Creates an IngestionManager appropriate for service-side use.
The returned IngestionManager will require its set_group_and_name method to be
called before its advance method may be called.
Args:
servicer: A base.Servicer for servicing the operation.
operation_context: A base.OperationContext for the operation to be passed to
the customer.
output_operator: A base.Operator for the operation to be passed to the
customer and to be called by the customer to accept operation data output
by the customer.
lock: The operation-wide lock.
pool: A thread pool in which to execute customer code.
termination_manager: The _interfaces.TerminationManager for the operation.
transmission_manager: The _interfaces.TransmissionManager for the
operation.
expiration_manager: The _interfaces.ExpirationManager for the operation.
protocol_manager: The _interfaces.ProtocolManager for the operation.
Returns:
An IngestionManager appropriate for service-side use.
"""
subscription_creator = _ServiceSubscriptionCreator(
servicer, operation_context, output_operator)
return _IngestionManager(
lock, pool, None, subscription_creator, termination_manager,
transmission_manager, expiration_manager, protocol_manager)
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