celery/celery/tests/test_worker/test_worker.py

import socket
import sys

from datetime import datetime, timedelta
from Queue import Empty

from kombu.transport.base import Message
from kombu.connection import BrokerConnection
from celery.utils.timer2 import Timer

from celery.app import app_or_default
from celery.concurrency.base import BasePool
from celery.exceptions import SystemTerminate
from celery.task import task as task_dec
from celery.task import periodic_task as periodic_task_dec
from celery.utils import gen_unique_id
from celery.worker import WorkController
from celery.worker.buckets import FastQueue
from celery.worker.job import TaskRequest
from celery.worker.consumer import Consumer as MainConsumer
from celery.worker.consumer import QoS, RUN
from celery.utils.serialization import pickle

from celery.tests.compat import catch_warnings
from celery.tests.utils import unittest
from celery.tests.utils import AppCase, execute_context, skip


class MockConsumer(object):

    class Channel(object):

        def close(self):
            pass

    def register_callback(self, cb):
        pass

    def consume(self):
        pass

    @property
    def channel(self):
        return self.Channel()


class PlaceHolder(object):
        pass


class MyKombuConsumer(MainConsumer):
    broadcast_consumer = MockConsumer()
    task_consumer = MockConsumer()

    def restart_heartbeat(self):
        self.heart = None


class MockNode(object):
    commands = []

    def handle_message(self, body, message):
        self.commands.append(body.pop("command", None))


class MockEventDispatcher(object):
    sent = []
    closed = False
    flushed = False
    _outbound_buffer = []

    def send(self, event, *args, **kwargs):
        self.sent.append(event)

    def close(self):
        self.closed = True

    def flush(self):
        self.flushed = True


class MockHeart(object):
    closed = False

    def stop(self):
        self.closed = True


@task_dec()
def foo_task(x, y, z, **kwargs):
    return x * y * z


@periodic_task_dec(run_every=60)
def foo_periodic_task():
    return "foo"


class MockLogger(object):

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

    def critical(self, msg, *args, **kwargs):
        self.logged.append(msg)

    def info(self, msg, *args, **kwargs):
        self.logged.append(msg)

    def error(self, msg, *args, **kwargs):
        self.logged.append(msg)

    def debug(self, msg, *args, **kwargs):
        self.logged.append(msg)


class MockBackend(object):
    _acked = False

    def basic_ack(self, delivery_tag):
        self._acked = True


class MockPool(BasePool):
    _terminated = False
    _stopped = False

    def __init__(self, *args, **kwargs):
        self.raise_regular = kwargs.get("raise_regular", False)
        self.raise_base = kwargs.get("raise_base", False)
        self.raise_SystemTerminate = kwargs.get("raise_SystemTerminate",
                                                False)

    def apply_async(self, *args, **kwargs):
        if self.raise_regular:
            raise KeyError("some exception")
        if self.raise_base:
            raise KeyboardInterrupt("Ctrl+c")
        if self.raise_SystemTerminate:
            raise SystemTerminate()

    def start(self):
        pass

    def stop(self):
        self._stopped = True
        return True

    def terminate(self):
        self._terminated = True
        self.stop()


class MockController(object):

    def __init__(self, w, *args, **kwargs):
        self._w = w
        self._stopped = False

    def start(self):
        self._w["started"] = True
        self._stopped = False

    def stop(self):
        self._stopped = True


def create_message(backend, **data):
    data.setdefault("id", gen_unique_id())
    return Message(backend, body=pickle.dumps(dict(**data)),
                   content_type="application/x-python-serialize",
                   content_encoding="binary")


class test_QoS(unittest.TestCase):

    class _QoS(QoS):
        def __init__(self, value):
            self.value = value
            QoS.__init__(self, None, value, None)

        def set(self, value):
            return value

    def test_qos_increment_decrement(self):
        qos = self._QoS(10)
        self.assertEqual(qos.increment(), 11)
        self.assertEqual(qos.increment(3), 14)
        self.assertEqual(qos.increment(-30), 14)
        self.assertEqual(qos.decrement(7), 7)
        self.assertEqual(qos.decrement(), 6)
        self.assertRaises(AssertionError, qos.decrement, 10)

    def test_qos_disabled_increment_decrement(self):
        qos = self._QoS(0)
        self.assertEqual(qos.increment(), 0)
        self.assertEqual(qos.increment(3), 0)
        self.assertEqual(qos.increment(-30), 0)
        self.assertEqual(qos.decrement(7), 0)
        self.assertEqual(qos.decrement(), 0)
        self.assertEqual(qos.decrement(10), 0)

    def test_qos_thread_safe(self):
        qos = self._QoS(10)

        def add():
            for i in xrange(1000):
                qos.increment()

        def sub():
            for i in xrange(1000):
                qos.decrement_eventually()

        def threaded(funs):
            from threading import Thread
            threads = [Thread(target=fun) for fun in funs]
            for thread in threads:
                thread.start()
            for thread in threads:
                thread.join()

        threaded([add, add])
        self.assertEqual(qos.value, 2010)

        qos.value = 1000
        threaded([add, sub])  # n = 2
        self.assertEqual(qos.value, 1000)

    class MockConsumer(object):
        prefetch_count = 0

        def qos(self, prefetch_size=0, prefetch_count=0, apply_global=False):
            self.prefetch_count = prefetch_count

    def test_consumer_increment_decrement(self):
        consumer = self.MockConsumer()
        qos = QoS(consumer, 10, app_or_default().log.get_default_logger())
        qos.update()
        self.assertEqual(qos.value, 10)
        self.assertEqual(consumer.prefetch_count, 10)
        qos.decrement()
        self.assertEqual(qos.value, 9)
        self.assertEqual(consumer.prefetch_count, 9)
        qos.decrement_eventually()
        self.assertEqual(qos.value, 8)
        self.assertEqual(consumer.prefetch_count, 9)

        # Does not decrement 0 value
        qos.value = 0
        qos.decrement()
        self.assertEqual(qos.value, 0)
        qos.increment()
        self.assertEqual(qos.value, 0)


class test_Consumer(unittest.TestCase):

    def setUp(self):
        self.ready_queue = FastQueue()
        self.eta_schedule = Timer()
        self.logger = app_or_default().log.get_default_logger()
        self.logger.setLevel(0)

    def tearDown(self):
        self.eta_schedule.stop()

    def test_info(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                           send_events=False)
        l.qos = QoS(l.task_consumer, 10, l.logger)
        info = l.info
        self.assertEqual(info["prefetch_count"], 10)
        self.assertFalse(info["broker"])

        l.connection = app_or_default().broker_connection()
        info = l.info
        self.assertTrue(info["broker"])

    def test_connection(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                           send_events=False)

        l.reset_connection()
        self.assertIsInstance(l.connection, BrokerConnection)

        l._state = RUN
        l.event_dispatcher = None
        l.stop_consumers(close=False)
        self.assertTrue(l.connection)

        l._state = RUN
        l.stop_consumers()
        self.assertIsNone(l.connection)
        self.assertIsNone(l.task_consumer)

        l.reset_connection()
        self.assertIsInstance(l.connection, BrokerConnection)
        l.stop_consumers()

        l.stop()
        l.close_connection()
        self.assertIsNone(l.connection)
        self.assertIsNone(l.task_consumer)

    def test_close_connection(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                           send_events=False)
        l._state = RUN
        l.close_connection()

        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                           send_events=False)
        eventer = l.event_dispatcher = MockEventDispatcher()
        heart = l.heart = MockHeart()
        l._state = RUN
        l.stop_consumers()
        self.assertTrue(eventer.closed)
        self.assertTrue(heart.closed)

    def test_receive_message_unknown(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                           send_events=False)
        backend = MockBackend()
        m = create_message(backend, unknown={"baz": "!!!"})
        l.event_dispatcher = MockEventDispatcher()
        l.pidbox_node = MockNode()

        def with_catch_warnings(log):
            l.receive_message(m.decode(), m)
            self.assertTrue(log)
            self.assertIn("unknown message", log[0].message.args[0])

        context = catch_warnings(record=True)
        execute_context(context, with_catch_warnings)

    def test_receive_message_eta_OverflowError(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                             send_events=False)
        backend = MockBackend()
        called = [False]

        def to_timestamp(d):
            called[0] = True
            raise OverflowError()

        m = create_message(backend, task=foo_task.name,
                                    args=("2, 2"),
                                    kwargs={},
                                    eta=datetime.now().isoformat())
        l.event_dispatcher = MockEventDispatcher()
        l.pidbox_node = MockNode()

        from celery.worker import consumer
        prev, consumer.to_timestamp = consumer.to_timestamp, to_timestamp
        try:
            l.receive_message(m.decode(), m)
            self.assertTrue(m.acknowledged)
            self.assertTrue(called[0])
        finally:
            consumer.to_timestamp = prev

    def test_receive_message_InvalidTaskError(self):
        logger = MockLogger()
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, logger,
                           send_events=False)
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name,
            args=(1, 2), kwargs="foobarbaz", id=1)
        l.event_dispatcher = MockEventDispatcher()
        l.pidbox_node = MockNode()

        l.receive_message(m.decode(), m)
        self.assertIn("Invalid task ignored", logger.logged[0])

    def test_on_decode_error(self):
        logger = MockLogger()
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, logger,
                           send_events=False)

        class MockMessage(object):
            content_type = "application/x-msgpack"
            content_encoding = "binary"
            body = "foobarbaz"
            acked = False

            def ack(self):
                self.acked = True

        message = MockMessage()
        l.on_decode_error(message, KeyError("foo"))
        self.assertTrue(message.acked)
        self.assertIn("Can't decode message body", logger.logged[0])

    def test_receieve_message(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                           send_events=False)
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name,
                           args=[2, 4, 8], kwargs={})

        l.event_dispatcher = MockEventDispatcher()
        l.receive_message(m.decode(), m)

        in_bucket = self.ready_queue.get_nowait()
        self.assertIsInstance(in_bucket, TaskRequest)
        self.assertEqual(in_bucket.task_name, foo_task.name)
        self.assertEqual(in_bucket.execute(), 2 * 4 * 8)
        self.assertTrue(self.eta_schedule.empty())

    def test_start_connection_error(self):

        class MockConsumer(MainConsumer):
            iterations = 0

            def consume_messages(self):
                if not self.iterations:
                    self.iterations = 1
                    raise KeyError("foo")
                raise SyntaxError("bar")

        l = MockConsumer(self.ready_queue, self.eta_schedule, self.logger,
                             send_events=False)
        l.connection_errors = (KeyError, )
        self.assertRaises(SyntaxError, l.start)
        l.heart.stop()

    def test_consume_messages(self):
        app = app_or_default()

        class Connection(app.broker_connection().__class__):
            obj = None

            def drain_events(self, **kwargs):
                self.obj.connection = None

        class Consumer(object):
            consuming = False
            prefetch_count = 0

            def consume(self):
                self.consuming = True

            def qos(self, prefetch_size=0, prefetch_count=0,
                            apply_global=False):
                self.prefetch_count = prefetch_count

        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                             send_events=False)
        l.connection = Connection()
        l.connection.obj = l
        l.task_consumer = Consumer()
        l.broadcast_consumer = Consumer()
        l.qos = QoS(l.task_consumer, 10, l.logger)

        l.consume_messages()
        l.consume_messages()
        self.assertTrue(l.task_consumer.consuming)
        self.assertTrue(l.broadcast_consumer.consuming)
        self.assertEqual(l.task_consumer.prefetch_count, 10)

        l.qos.decrement()
        l.consume_messages()
        self.assertEqual(l.task_consumer.prefetch_count, 9)

    def test_maybe_conn_error(self):

        def raises(error):

            def fun():
                raise error

            return fun

        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                             send_events=False)
        l.connection_errors = (KeyError, )
        l.channel_errors = (SyntaxError, )
        l.maybe_conn_error(raises(AttributeError("foo")))
        l.maybe_conn_error(raises(KeyError("foo")))
        l.maybe_conn_error(raises(SyntaxError("foo")))
        self.assertRaises(IndexError, l.maybe_conn_error,
                raises(IndexError("foo")))

    def test_apply_eta_task(self):
        from celery.worker import state
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                             send_events=False)
        l.qos = QoS(None, 10, l.logger)

        task = object()
        qos = l.qos.value
        l.apply_eta_task(task)
        self.assertIn(task, state.reserved_requests)
        self.assertEqual(l.qos.value, qos - 1)
        self.assertIs(self.ready_queue.get_nowait(), task)

    def test_receieve_message_eta_isoformat(self):

        class MockConsumer(object):
            prefetch_count_incremented = False

            def qos(self, **kwargs):
                self.prefetch_count_incremented = True

        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                             send_events=False)
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name,
                           eta=datetime.now().isoformat(),
                           args=[2, 4, 8], kwargs={})

        l.task_consumer = MockConsumer()
        l.qos = QoS(l.task_consumer, l.initial_prefetch_count, l.logger)
        l.event_dispatcher = MockEventDispatcher()
        l.receive_message(m.decode(), m)
        l.eta_schedule.stop()

        items = [entry[2] for entry in self.eta_schedule.queue]
        found = 0
        for item in items:
            print("ITEM: %r" % (item, ) )
            if item.args[0].task_name == foo_task.name:
                found = True
        self.assertTrue(found)
        self.assertTrue(l.task_consumer.prefetch_count_incremented)
        l.eta_schedule.stop()

    def test_revoke(self):
        ready_queue = FastQueue()
        l = MyKombuConsumer(ready_queue, self.eta_schedule, self.logger,
                           send_events=False)
        backend = MockBackend()
        id = gen_unique_id()
        t = create_message(backend, task=foo_task.name, args=[2, 4, 8],
                           kwargs={}, id=id)
        from celery.worker.state import revoked
        revoked.add(id)

        l.receive_message(t.decode(), t)
        self.assertTrue(ready_queue.empty())

    def test_receieve_message_not_registered(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                          send_events=False)
        backend = MockBackend()
        m = create_message(backend, task="x.X.31x", args=[2, 4, 8], kwargs={})

        l.event_dispatcher = MockEventDispatcher()
        self.assertFalse(l.receive_message(m.decode(), m))
        self.assertRaises(Empty, self.ready_queue.get_nowait)
        self.assertTrue(self.eta_schedule.empty())

    def test_receieve_message_eta(self):
        l = MyKombuConsumer(self.ready_queue, self.eta_schedule, self.logger,
                          send_events=False)
        l.event_dispatcher = MockEventDispatcher()
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name,
                           args=[2, 4, 8], kwargs={},
                           eta=(datetime.now() +
                               timedelta(days=1)).isoformat())

        l.reset_connection()
        p = l.app.conf.BROKER_CONNECTION_RETRY
        l.app.conf.BROKER_CONNECTION_RETRY = False
        try:
            l.reset_connection()
        finally:
            l.app.conf.BROKER_CONNECTION_RETRY = p
        l.stop_consumers()
        l.event_dispatcher = MockEventDispatcher()
        l.receive_message(m.decode(), m)
        l.eta_schedule.stop()
        in_hold = self.eta_schedule.queue[0]
        self.assertEqual(len(in_hold), 3)
        eta, priority, entry = in_hold
        task = entry.args[0]
        self.assertIsInstance(task, TaskRequest)
        self.assertEqual(task.task_name, foo_task.name)
        self.assertEqual(task.execute(), 2 * 4 * 8)
        self.assertRaises(Empty, self.ready_queue.get_nowait)

    def test_start__consume_messages(self):

        class _QoS(object):
            prev = 3
            value = 4

            def update(self):
                self.prev = self.value

        class _Consumer(MyKombuConsumer):
            iterations = 0
            wait_method = None

            def reset_connection(self):
                if self.iterations >= 1:
                    raise KeyError("foo")

        called_back = [False]

        def init_callback(consumer):
            called_back[0] = True

        l = _Consumer(self.ready_queue, self.eta_schedule, self.logger,
                      send_events=False, init_callback=init_callback)
        l.task_consumer = MockConsumer()
        l.broadcast_consumer = MockConsumer()
        l.qos = _QoS()
        l.connection = BrokerConnection()
        l.iterations = 0

        def raises_KeyError(limit=None):
            l.iterations += 1
            if l.qos.prev != l.qos.value:
                l.qos.update()
            if l.iterations >= 2:
                raise KeyError("foo")

        l.consume_messages = raises_KeyError
        self.assertRaises(KeyError, l.start)
        self.assertTrue(called_back[0])
        self.assertEqual(l.iterations, 1)
        self.assertEqual(l.qos.prev, l.qos.value)

        l = _Consumer(self.ready_queue, self.eta_schedule, self.logger,
                      send_events=False, init_callback=init_callback)
        l.qos = _QoS()
        l.task_consumer = MockConsumer()
        l.broadcast_consumer = MockConsumer()
        l.connection = BrokerConnection()

        def raises_socket_error(limit=None):
            l.iterations = 1
            raise socket.error("foo")

        l.consume_messages = raises_socket_error
        self.assertRaises(socket.error, l.start)
        self.assertTrue(called_back[0])
        self.assertEqual(l.iterations, 1)


class test_WorkController(AppCase):

    def setup(self):
        self.worker = self.create_worker()

    def create_worker(self, **kw):
        worker = WorkController(concurrency=1, loglevel=0, **kw)
        worker.logger = MockLogger()
        return worker

    def test_process_initializer(self):
        from celery import Celery
        from celery import platforms
        from celery import signals
        from celery.app import _tls
        from celery.worker import process_initializer
        from celery.worker import WORKER_SIGRESET, WORKER_SIGIGNORE

        ignored_signals = []
        reset_signals = []
        worker_init = [False]
        default_app = app_or_default()
        app = Celery(loader="default", set_as_current=False)

        class Loader(object):

            def init_worker(self):
                worker_init[0] = True
        app.loader = Loader()

        def on_worker_process_init(**kwargs):
            on_worker_process_init.called = True
        on_worker_process_init.called = False
        signals.worker_process_init.connect(on_worker_process_init)

        def set_mp_process_title(title, hostname=None):
            set_mp_process_title.called = (title, hostname)
        set_mp_process_title.called = ()

        pignore_signal = platforms.ignore_signal
        preset_signal = platforms.reset_signal
        psetproctitle = platforms.set_mp_process_title
        platforms.ignore_signal = lambda sig: ignored_signals.append(sig)
        platforms.reset_signal = lambda sig: reset_signals.append(sig)
        platforms.set_mp_process_title = set_mp_process_title
        try:
            process_initializer(app, "awesome.worker.com")
            self.assertItemsEqual(ignored_signals, WORKER_SIGIGNORE)
            self.assertItemsEqual(reset_signals, WORKER_SIGRESET)
            self.assertTrue(worker_init[0])
            self.assertTrue(on_worker_process_init.called)
            self.assertIs(_tls.current_app, app)
            self.assertTupleEqual(set_mp_process_title.called,
                                  ("celeryd", "awesome.worker.com"))
        finally:
            platforms.ignore_signal = pignore_signal
            platforms.reset_signal = preset_signal
            platforms.set_mp_process_title = psetproctitle
            default_app.set_current()

    def test_with_rate_limits_disabled(self):
        worker = WorkController(concurrency=1, loglevel=0,
                                disable_rate_limits=True)
        self.assertTrue(hasattr(worker.ready_queue, "put"))

    def test_attrs(self):
        worker = self.worker
        self.assertIsInstance(worker.scheduler, Timer)
        self.assertTrue(worker.scheduler)
        self.assertTrue(worker.pool)
        self.assertTrue(worker.consumer)
        self.assertTrue(worker.mediator)
        self.assertTrue(worker.components)

    def test_with_embedded_celerybeat(self):
        worker = WorkController(concurrency=1, loglevel=0,
                                embed_clockservice=True)
        self.assertTrue(worker.beat)
        self.assertIn(worker.beat, worker.components)

    def test_with_autoscaler(self):
        worker = self.create_worker(autoscale=[10, 3], send_events=False,
                                eta_scheduler_cls="celery.utils.timer2.Timer")
        self.assertTrue(worker.autoscaler)

    def test_dont_stop_or_terminate(self):
        worker = WorkController(concurrency=1, loglevel=0)
        worker.stop()
        self.assertNotEqual(worker._state, worker.CLOSE)
        worker.terminate()
        self.assertNotEqual(worker._state, worker.CLOSE)

        sigsafe, worker.pool.signal_safe = worker.pool.signal_safe, False
        try:
            worker._state = worker.RUN
            worker.stop(in_sighandler=True)
            self.assertNotEqual(worker._state, worker.CLOSE)
            worker.terminate(in_sighandler=True)
            self.assertNotEqual(worker._state, worker.CLOSE)
        finally:
            worker.pool.signal_safe = sigsafe

    def test_on_timer_error(self):
        worker = WorkController(concurrency=1, loglevel=0)
        worker.logger = MockLogger()

        try:
            raise KeyError("foo")
        except KeyError:
            exc_info = sys.exc_info()

        worker.on_timer_error(exc_info)
        logged = worker.logger.logged[0]
        self.assertIn("KeyError", logged)

    def test_on_timer_tick(self):
        worker = WorkController(concurrency=1, loglevel=10)
        worker.logger = MockLogger()
        worker.timer_debug = worker.logger.debug

        worker.on_timer_tick(30.0)
        logged = worker.logger.logged[0]
        self.assertIn("30.0", logged)

    def test_process_task(self):
        worker = self.worker
        worker.pool = MockPool()
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name, args=[4, 8, 10],
                           kwargs={})
        task = TaskRequest.from_message(m, m.decode())
        worker.process_task(task)
        worker.pool.stop()

    def test_process_task_raise_base(self):
        worker = self.worker
        worker.pool = MockPool(raise_base=True)
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name, args=[4, 8, 10],
                           kwargs={})
        task = TaskRequest.from_message(m, m.decode())
        worker.components = []
        worker._state = worker.RUN
        self.assertRaises(KeyboardInterrupt, worker.process_task, task)
        self.assertEqual(worker._state, worker.TERMINATE)

    def test_process_task_raise_SystemTerminate(self):
        worker = self.worker
        worker.pool = MockPool(raise_SystemTerminate=True)
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name, args=[4, 8, 10],
                           kwargs={})
        task = TaskRequest.from_message(m, m.decode())
        worker.components = []
        worker._state = worker.RUN
        self.assertRaises(SystemExit, worker.process_task, task)
        self.assertEqual(worker._state, worker.TERMINATE)

    def test_process_task_raise_regular(self):
        worker = self.worker
        worker.pool = MockPool(raise_regular=True)
        backend = MockBackend()
        m = create_message(backend, task=foo_task.name, args=[4, 8, 10],
                           kwargs={})
        task = TaskRequest.from_message(m, m.decode())
        worker.process_task(task)
        worker.pool.stop()

    def test_start_catches_base_exceptions(self):

        class Component(object):
            stopped = False
            terminated = False

            def __init__(self, exc):
                self.exc = exc

            def start(self):
                raise self.exc

            def terminate(self):
                self.terminated = True

            def stop(self):
                self.stopped = True

        worker1 = self.create_worker()
        worker1.components = [Component(SystemTerminate())]
        self.assertRaises(SystemExit, worker1.start)
        self.assertTrue(worker1.components[0].terminated)

        worker2 = self.create_worker()
        worker2.components = [Component(SystemExit())]
        self.assertRaises(SystemExit, worker2.start)
        self.assertTrue(worker2.components[0].stopped)

    def test_state_db(self):
        from celery.worker import state
        Persistent = state.Persistent

        class MockPersistent(Persistent):

            def _load(self):
                return {}

        state.Persistent = MockPersistent
        try:
            worker = self.create_worker(db="statefilename")
            self.assertTrue(worker._finalize_db)
            worker._finalize_db.cancel()
        finally:
            state.Persistent = Persistent

    @skip("Issue #264")
    def test_disable_rate_limits(self):
        from celery.worker.buckets import FastQueue
        worker = self.create_worker(disable_rate_limits=True)
        self.assertIsInstance(worker.ready_queue, FastQueue)
        self.assertIsNone(worker.mediator)
        self.assertEqual(worker.ready_queue.put, worker.process_task)

    def test_start__stop(self):
        worker = self.worker
        w1 = {"started": False}
        w2 = {"started": False}
        w3 = {"started": False}
        w4 = {"started": False}
        worker.components = [MockController(w1), MockController(w2),
                             MockController(w3), MockController(w4)]

        worker.start()
        for w in (w1, w2, w3, w4):
            self.assertTrue(w["started"])
        self.assertTrue(worker._running, len(worker.components))
        worker.stop()
        for component in worker.components:
            self.assertTrue(component._stopped)

    def test_start__terminate(self):
        worker = self.worker
        w1 = {"started": False}
        w2 = {"started": False}
        w3 = {"started": False}
        w4 = {"started": False}
        worker.components = [MockController(w1), MockController(w2),
                             MockController(w3), MockController(w4),
                             MockPool()]

        worker.start()
        for w in (w1, w2, w3, w4):
            self.assertTrue(w["started"])
        self.assertTrue(worker._running, len(worker.components))
        self.assertEqual(worker._state, RUN)
        worker.terminate()
        for component in worker.components:
            self.assertTrue(component._stopped)
        self.assertTrue(worker.components[4]._terminated)