heat/heat/openstack/common/rpc/impl_fake.py

# vim: tabstop=4 shiftwidth=4 softtabstop=4

#    Copyright 2011 OpenStack LLC
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.
"""Fake RPC implementation which calls proxy methods directly with no
queues.  Casts will block, but this is very useful for tests.
"""

import inspect
# NOTE(russellb): We specifically want to use json, not our own jsonutils.
# jsonutils has some extra logic to automatically convert objects to primitive
# types so that they can be serialized.  We want to catch all cases where
# non-primitive types make it into this code and treat it as an error.
import json
import time

import eventlet

from heat.openstack.common.rpc import common as rpc_common

CONSUMERS = {}


class RpcContext(rpc_common.CommonRpcContext):
    def __init__(self, **kwargs):
        super(RpcContext, self).__init__(**kwargs)
        self._response = []
        self._done = False

    def deepcopy(self):
        values = self.to_dict()
        new_inst = self.__class__(**values)
        new_inst._response = self._response
        new_inst._done = self._done
        return new_inst

    def reply(self, reply=None, failure=None, ending=False):
        if ending:
            self._done = True
        if not self._done:
            self._response.append((reply, failure))


class Consumer(object):
    def __init__(self, topic, proxy):
        self.topic = topic
        self.proxy = proxy

    def call(self, context, version, method, args, timeout):
        done = eventlet.event.Event()

        def _inner():
            ctxt = RpcContext.from_dict(context.to_dict())
            try:
                rval = self.proxy.dispatch(context, version, method, **args)
                res = []
                # Caller might have called ctxt.reply() manually
                for (reply, failure) in ctxt._response:
                    if failure:
                        raise failure[0], failure[1], failure[2]
                    res.append(reply)
                # if ending not 'sent'...we might have more data to
                # return from the function itself
                if not ctxt._done:
                    if inspect.isgenerator(rval):
                        for val in rval:
                            res.append(val)
                    else:
                        res.append(rval)
                done.send(res)
            except rpc_common.ClientException as e:
                done.send_exception(e._exc_info[1])
            except Exception as e:
                done.send_exception(e)

        thread = eventlet.greenthread.spawn(_inner)

        if timeout:
            start_time = time.time()
            while not done.ready():
                eventlet.greenthread.sleep(1)
                cur_time = time.time()
                if (cur_time - start_time) > timeout:
                    thread.kill()
                    raise rpc_common.Timeout()

        return done.wait()


class Connection(object):
    """Connection object."""

    def __init__(self):
        self.consumers = []

    def create_consumer(self, topic, proxy, fanout=False):
        consumer = Consumer(topic, proxy)
        self.consumers.append(consumer)
        if topic not in CONSUMERS:
            CONSUMERS[topic] = []
        CONSUMERS[topic].append(consumer)

    def close(self):
        for consumer in self.consumers:
            CONSUMERS[consumer.topic].remove(consumer)
        self.consumers = []

    def consume_in_thread(self):
        pass


def create_connection(conf, new=True):
    """Create a connection"""
    return Connection()


def check_serialize(msg):
    """Make sure a message intended for rpc can be serialized."""
    json.dumps(msg)


def multicall(conf, context, topic, msg, timeout=None):
    """Make a call that returns multiple times."""

    check_serialize(msg)

    method = msg.get('method')
    if not method:
        return
    args = msg.get('args', {})
    version = msg.get('version', None)

    try:
        consumer = CONSUMERS[topic][0]
    except (KeyError, IndexError):
        return iter([None])
    else:
        return consumer.call(context, version, method, args, timeout)


def call(conf, context, topic, msg, timeout=None):
    """Sends a message on a topic and wait for a response."""
    rv = multicall(conf, context, topic, msg, timeout)
    # NOTE(vish): return the last result from the multicall
    rv = list(rv)
    if not rv:
        return
    return rv[-1]


def cast(conf, context, topic, msg):
    check_serialize(msg)
    try:
        call(conf, context, topic, msg)
    except Exception:
        pass


def notify(conf, context, topic, msg, envelope):
    check_serialize(msg)


def cleanup():
    pass


def fanout_cast(conf, context, topic, msg):
    """Cast to all consumers of a topic"""
    check_serialize(msg)
    method = msg.get('method')
    if not method:
        return
    args = msg.get('args', {})
    version = msg.get('version', None)

    for consumer in CONSUMERS.get(topic, []):
        try:
            consumer.call(context, version, method, args, None)
        except Exception:
            pass