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# Copyright 2015-2016, 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.
"""The RPC-invocation-side bridge between RPC Framework and GRPC-on-the-wire."""
import abc
import enum
import logging
import threading
import time
import six
from grpc._adapter import _intermediary_low
from grpc._links import _constants
from grpc.beta import interfaces as beta_interfaces
from grpc.framework.foundation import activated
from grpc.framework.foundation import logging_pool
from grpc.framework.foundation import relay
from grpc.framework.interfaces.links import links
_IDENTITY = lambda x: x
_STOP = _intermediary_low.Event.Kind.STOP
_WRITE = _intermediary_low.Event.Kind.WRITE_ACCEPTED
_COMPLETE = _intermediary_low.Event.Kind.COMPLETE_ACCEPTED
_READ = _intermediary_low.Event.Kind.READ_ACCEPTED
_METADATA = _intermediary_low.Event.Kind.METADATA_ACCEPTED
_FINISH = _intermediary_low.Event.Kind.FINISH
@enum.unique
class _Read(enum.Enum):
AWAITING_METADATA = 'awaiting metadata'
READING = 'reading'
AWAITING_ALLOWANCE = 'awaiting allowance'
CLOSED = 'closed'
@enum.unique
class _HighWrite(enum.Enum):
OPEN = 'open'
CLOSED = 'closed'
@enum.unique
class _LowWrite(enum.Enum):
OPEN = 'OPEN'
ACTIVE = 'ACTIVE'
CLOSED = 'CLOSED'
class _Context(beta_interfaces.GRPCInvocationContext):
def __init__(self):
self._lock = threading.Lock()
self._disable_next_compression = False
def disable_next_request_compression(self):
with self._lock:
self._disable_next_compression = True
def next_compression_disabled(self):
with self._lock:
disabled = self._disable_next_compression
self._disable_next_compression = False
return disabled
class _RPCState(object):
def __init__(
self, call, request_serializer, response_deserializer, sequence_number,
read, allowance, high_write, low_write, due, context):
self.call = call
self.request_serializer = request_serializer
self.response_deserializer = response_deserializer
self.sequence_number = sequence_number
self.read = read
self.allowance = allowance
self.high_write = high_write
self.low_write = low_write
self.due = due
self.context = context
def _no_longer_due(kind, rpc_state, key, rpc_states):
rpc_state.due.remove(kind)
if not rpc_state.due:
del rpc_states[key]
class _Kernel(object):
def __init__(
self, channel, host, metadata_transformer, request_serializers,
response_deserializers, ticket_relay):
self._lock = threading.Lock()
self._channel = channel
self._host = host
self._metadata_transformer = metadata_transformer
self._request_serializers = request_serializers
self._response_deserializers = response_deserializers
self._relay = ticket_relay
self._completion_queue = None
self._rpc_states = {}
self._pool = None
def _on_write_event(self, operation_id, unused_event, rpc_state):
if rpc_state.high_write is _HighWrite.CLOSED:
rpc_state.call.complete(operation_id)
rpc_state.due.add(_COMPLETE)
rpc_state.due.remove(_WRITE)
rpc_state.low_write = _LowWrite.CLOSED
else:
ticket = links.Ticket(
operation_id, rpc_state.sequence_number, None, None, None, None, 1,
None, None, None, None, None, None, None)
rpc_state.sequence_number += 1
self._relay.add_value(ticket)
rpc_state.low_write = _LowWrite.OPEN
_no_longer_due(_WRITE, rpc_state, operation_id, self._rpc_states)
def _on_read_event(self, operation_id, event, rpc_state):
if event.bytes is None or _FINISH not in rpc_state.due:
rpc_state.read = _Read.CLOSED
_no_longer_due(_READ, rpc_state, operation_id, self._rpc_states)
else:
if 0 < rpc_state.allowance:
rpc_state.allowance -= 1
rpc_state.call.read(operation_id)
else:
rpc_state.read = _Read.AWAITING_ALLOWANCE
_no_longer_due(_READ, rpc_state, operation_id, self._rpc_states)
ticket = links.Ticket(
operation_id, rpc_state.sequence_number, None, None, None, None, None,
None, rpc_state.response_deserializer(event.bytes), None, None, None,
None, None)
rpc_state.sequence_number += 1
self._relay.add_value(ticket)
def _on_metadata_event(self, operation_id, event, rpc_state):
if _FINISH in rpc_state.due:
rpc_state.allowance -= 1
rpc_state.call.read(operation_id)
rpc_state.read = _Read.READING
rpc_state.due.add(_READ)
rpc_state.due.remove(_METADATA)
ticket = links.Ticket(
operation_id, rpc_state.sequence_number, None, None,
links.Ticket.Subscription.FULL, None, None, event.metadata, None,
None, None, None, None, None)
rpc_state.sequence_number += 1
self._relay.add_value(ticket)
else:
_no_longer_due(_METADATA, rpc_state, operation_id, self._rpc_states)
def _on_finish_event(self, operation_id, event, rpc_state):
_no_longer_due(_FINISH, rpc_state, operation_id, self._rpc_states)
if event.status.code == _intermediary_low.Code.OK:
termination = links.Ticket.Termination.COMPLETION
elif event.status.code == _intermediary_low.Code.CANCELLED:
termination = links.Ticket.Termination.CANCELLATION
elif event.status.code == _intermediary_low.Code.DEADLINE_EXCEEDED:
termination = links.Ticket.Termination.EXPIRATION
elif event.status.code == _intermediary_low.Code.UNIMPLEMENTED:
termination = links.Ticket.Termination.REMOTE_FAILURE
elif event.status.code == _intermediary_low.Code.UNKNOWN:
termination = links.Ticket.Termination.LOCAL_FAILURE
else:
termination = links.Ticket.Termination.TRANSMISSION_FAILURE
code = _constants.LOW_STATUS_CODE_TO_HIGH_STATUS_CODE[event.status.code]
ticket = links.Ticket(
operation_id, rpc_state.sequence_number, None, None, None, None, None,
None, None, event.metadata, code, event.status.details, termination,
None)
rpc_state.sequence_number += 1
self._relay.add_value(ticket)
def _spin(self, completion_queue):
while True:
event = completion_queue.get(None)
with self._lock:
rpc_state = self._rpc_states.get(event.tag, None)
if event.kind is _STOP:
pass
elif event.kind is _WRITE:
self._on_write_event(event.tag, event, rpc_state)
elif event.kind is _METADATA:
self._on_metadata_event(event.tag, event, rpc_state)
elif event.kind is _READ:
self._on_read_event(event.tag, event, rpc_state)
elif event.kind is _FINISH:
self._on_finish_event(event.tag, event, rpc_state)
elif event.kind is _COMPLETE:
_no_longer_due(_COMPLETE, rpc_state, event.tag, self._rpc_states)
else:
logging.error('Illegal RPC event! %s', (event,))
if self._completion_queue is None and not self._rpc_states:
completion_queue.stop()
return
def _invoke(
self, operation_id, group, method, initial_metadata, payload, termination,
timeout, allowance, options):
"""Invoke an RPC.
Args:
operation_id: Any object to be used as an operation ID for the RPC.
group: The group to which the RPC method belongs.
method: The RPC method name.
initial_metadata: The initial metadata object for the RPC.
payload: A payload object for the RPC or None if no payload was given at
invocation-time.
termination: A links.Ticket.Termination value or None indicated whether or
not more writes will follow from this side of the RPC.
timeout: A duration of time in seconds to allow for the RPC.
allowance: The number of payloads (beyond the free first one) that the
local ticket exchange mate has granted permission to be read.
options: A beta_interfaces.GRPCCallOptions value or None.
"""
if termination is links.Ticket.Termination.COMPLETION:
high_write = _HighWrite.CLOSED
elif termination is None:
high_write = _HighWrite.OPEN
else:
return
transformed_initial_metadata = self._metadata_transformer(initial_metadata)
request_serializer = self._request_serializers.get(
(group, method), _IDENTITY)
response_deserializer = self._response_deserializers.get(
(group, method), _IDENTITY)
call = _intermediary_low.Call(
self._channel, self._completion_queue, '/%s/%s' % (group, method),
self._host, time.time() + timeout)
if options is not None and options.credentials is not None:
call.set_credentials(options.credentials._low_credentials)
if transformed_initial_metadata is not None:
for metadata_key, metadata_value in transformed_initial_metadata:
call.add_metadata(metadata_key, metadata_value)
call.invoke(self._completion_queue, operation_id, operation_id)
if payload is None:
if high_write is _HighWrite.CLOSED:
call.complete(operation_id)
low_write = _LowWrite.CLOSED
due = set((_METADATA, _COMPLETE, _FINISH,))
else:
low_write = _LowWrite.OPEN
due = set((_METADATA, _FINISH,))
else:
if options is not None and options.disable_compression:
flags = _intermediary_low.WriteFlags.WRITE_NO_COMPRESS
else:
flags = 0
call.write(request_serializer(payload), operation_id, flags)
low_write = _LowWrite.ACTIVE
due = set((_WRITE, _METADATA, _FINISH,))
context = _Context()
self._rpc_states[operation_id] = _RPCState(
call, request_serializer, response_deserializer, 1,
_Read.AWAITING_METADATA, 1 if allowance is None else (1 + allowance),
high_write, low_write, due, context)
protocol = links.Protocol(links.Protocol.Kind.INVOCATION_CONTEXT, context)
ticket = links.Ticket(
operation_id, 0, None, None, None, None, None, None, None, None, None,
None, None, protocol)
self._relay.add_value(ticket)
def _advance(self, operation_id, rpc_state, payload, termination, allowance):
if payload is not None:
disable_compression = rpc_state.context.next_compression_disabled()
if disable_compression:
flags = _intermediary_low.WriteFlags.WRITE_NO_COMPRESS
else:
flags = 0
rpc_state.call.write(
rpc_state.request_serializer(payload), operation_id, flags)
rpc_state.low_write = _LowWrite.ACTIVE
rpc_state.due.add(_WRITE)
if allowance is not None:
if rpc_state.read is _Read.AWAITING_ALLOWANCE:
rpc_state.allowance += allowance - 1
rpc_state.call.read(operation_id)
rpc_state.read = _Read.READING
rpc_state.due.add(_READ)
else:
rpc_state.allowance += allowance
if termination is links.Ticket.Termination.COMPLETION:
rpc_state.high_write = _HighWrite.CLOSED
if rpc_state.low_write is _LowWrite.OPEN:
rpc_state.call.complete(operation_id)
rpc_state.due.add(_COMPLETE)
rpc_state.low_write = _LowWrite.CLOSED
elif termination is not None:
rpc_state.call.cancel()
def add_ticket(self, ticket):
with self._lock:
if ticket.sequence_number == 0:
if self._completion_queue is None:
logging.error('Received invocation ticket %s after stop!', ticket)
else:
if (ticket.protocol is not None and
ticket.protocol.kind is links.Protocol.Kind.CALL_OPTION):
grpc_call_options = ticket.protocol.value
else:
grpc_call_options = None
self._invoke(
ticket.operation_id, ticket.group, ticket.method,
ticket.initial_metadata, ticket.payload, ticket.termination,
ticket.timeout, ticket.allowance, grpc_call_options)
else:
rpc_state = self._rpc_states.get(ticket.operation_id)
if rpc_state is not None:
self._advance(
ticket.operation_id, rpc_state, ticket.payload,
ticket.termination, ticket.allowance)
def start(self):
"""Starts this object.
This method must be called before attempting to exchange tickets with this
object.
"""
with self._lock:
self._completion_queue = _intermediary_low.CompletionQueue()
self._pool = logging_pool.pool(1)
self._pool.submit(self._spin, self._completion_queue)
def stop(self):
"""Stops this object.
This method must be called for proper termination of this object, and no
attempts to exchange tickets with this object may be made after this method
has been called.
"""
with self._lock:
if not self._rpc_states:
self._completion_queue.stop()
self._completion_queue = None
pool = self._pool
pool.shutdown(wait=True)
class InvocationLink(six.with_metaclass(abc.ABCMeta, links.Link, activated.Activated)):
"""A links.Link for use on the invocation-side of a gRPC connection.
Implementations of this interface are only valid for use when activated.
"""
class _InvocationLink(InvocationLink):
def __init__(
self, channel, host, metadata_transformer, request_serializers,
response_deserializers):
self._relay = relay.relay(None)
self._kernel = _Kernel(
channel, host,
_IDENTITY if metadata_transformer is None else metadata_transformer,
{} if request_serializers is None else request_serializers,
{} if response_deserializers is None else response_deserializers,
self._relay)
def _start(self):
self._relay.start()
self._kernel.start()
return self
def _stop(self):
self._kernel.stop()
self._relay.stop()
def accept_ticket(self, ticket):
"""See links.Link.accept_ticket for specification."""
self._kernel.add_ticket(ticket)
def join_link(self, link):
"""See links.Link.join_link for specification."""
self._relay.set_behavior(link.accept_ticket)
def __enter__(self):
"""See activated.Activated.__enter__ for specification."""
return self._start()
def __exit__(self, exc_type, exc_val, exc_tb):
"""See activated.Activated.__exit__ for specification."""
self._stop()
return False
def start(self):
"""See activated.Activated.start for specification."""
return self._start()
def stop(self):
"""See activated.Activated.stop for specification."""
self._stop()
def invocation_link(
channel, host, metadata_transformer, request_serializers,
response_deserializers):
"""Creates an InvocationLink.
Args:
channel: An _intermediary_low.Channel for use by the link.
host: The host to specify when invoking RPCs.
metadata_transformer: A callable that takes an invocation-side initial
metadata value and returns another metadata value to send in its place.
May be None.
request_serializers: A dict from group-method pair to request object
serialization behavior.
response_deserializers: A dict from group-method pair to response object
deserialization behavior.
Returns:
An InvocationLink.
"""
return _InvocationLink(
channel, host, metadata_transformer, request_serializers,
response_deserializers)
|