def setUp(self):
self.clock = Clock()
self.engine = get_engine(LOG_STATS_INTERVAL=30)
self.engine.signals = SignalManager(self.engine)
self.ls = LogStats(self.engine, clock=self.clock)
self.lw = LogWrapper()
self.lw.setUp()
def get_engine(custom_settings=None, **kwargs):
'''Return the engine initialized with the custom settings.
'''
custom_settings = custom_settings or {}
custom_settings.update(kwargs)
settings = EngineSettings(custom_settings=custom_settings)
engine = Engine(settings, Project(path=None), clock=Clock())
engine.set_spider(BaseSpider('dummy'))
engine.stop_if_idle = False
# it is common to use stats and signals in unittests, without full
# initialization of the engine
engine.stats = MemoryStats(engine)
engine.signals = SignalManager(engine)
return engine
def setup(self):
assert self.spider is not None, 'Spider is not set in Engine.'
# IMPORTANT: order of the following initializations is very important
# so please, think twice about any changes to it
# initialize logging
if self.settings.get_bool('LOG_ENABLED'):
log.start(self.settings['LOG_FILE'], self.settings['LOG_LEVEL'],
self.settings['LOG_STDOUT'],
self.settings['LOG_ENCODING'])
# initialize signals
self.signals = SignalManager(self)
#initialize stats
stats_cls = load_object(self.settings.get('STATS_CLASS'))
self.stats = stats_cls(self)
# initialize downloader
self.request_queue = PriorityQueue(lambda _: MemoryQueue())
self.response_queue = ResponseQueue(
self.settings.get_int('RESPONSE_ACTIVE_SIZE_LIMIT'))
self.downloader = Downloader(self.settings,
self.request_queue,
self.response_queue,
clock=self.clock)
# initialize extensions
self.extensions = ExtensionManager(self)
# initialize downloader pipeline
self.pipeline = PipelineManager(self)
self.initialized = True
# now that everything is ready, set the spider's engine
self.spider.set_engine(self)
def setup(self):
assert self.spider is not None, 'Spider is not set in Engine.'
# IMPORTANT: order of the following initializations is very important
# so please, think twice about any changes to it
# initialize logging
if self.settings.get_bool('LOG_ENABLED'):
log.start(
self.settings['LOG_FILE'],
self.settings['LOG_LEVEL'],
self.settings['LOG_STDOUT'],
self.settings['LOG_ENCODING'])
# initialize signals
self.signals = SignalManager(self)
#initialize stats
stats_cls = load_object(self.settings.get('STATS_CLASS'))
self.stats = stats_cls(self)
# initialize downloader
self.request_queue = PriorityQueue(lambda _: MemoryQueue())
self.response_queue = ResponseQueue(
self.settings.get_int('RESPONSE_ACTIVE_SIZE_LIMIT'))
self.downloader = Downloader(self.settings, self.request_queue,
self.response_queue, clock=self.clock)
# initialize extensions
self.extensions = ExtensionManager(self)
# initialize downloader pipeline
self.pipeline = PipelineManager(self)
self.initialized = True
# now that everything is ready, set the spider's engine
self.spider.set_engine(self)
class Engine(object):
'''
WARNING: don't stop() and start() engine. Use pause() and unpause(),
instead.
'''
# how many seconds to wait between the checks of response_queue
QUEUE_CHECK_FREQUENCY = 0.1
# how often to check is still paused
PAUSED_CHECK_FREQUENCY = 5
# how often to check if being idle
IDLE_CHECK_FREQUENCY = 5
def __init__(self, settings, project, command_invoked='', clock=None):
'''Constructor of Engine should be very lightweight, so that things
can be easily unittested. For any more complicated initialization
use `setup()`.
'''
self.settings = settings
self.project = project
self.spiders = SpiderManager(settings)
self.stop_if_idle = True
self.initialized = False # True, when `setup()` has been called
# name of the command invoking the engine. E.g. `crawl`, `shell`, etc.
self.command_invoked = command_invoked
self.spider = None
self.pending_requests = 0
self.running = False
self.paused = False
# clock is used in unittests
self.clock = clock or reactor
self.processing = ScheduledCall(self._process_queue, clock=self.clock)
def set_spider(self, spider):
self.spider = spider
self.settings.spider_settings = spider.spider_settings()
def setup(self):
assert self.spider is not None, 'Spider is not set in Engine.'
# IMPORTANT: order of the following initializations is very important
# so please, think twice about any changes to it
# initialize logging
if self.settings.get_bool('LOG_ENABLED'):
log.start(
self.settings['LOG_FILE'],
self.settings['LOG_LEVEL'],
self.settings['LOG_STDOUT'],
self.settings['LOG_ENCODING'])
# initialize signals
self.signals = SignalManager(self)
#initialize stats
stats_cls = load_object(self.settings.get('STATS_CLASS'))
self.stats = stats_cls(self)
# initialize downloader
self.request_queue = PriorityQueue(lambda _: MemoryQueue())
self.response_queue = ResponseQueue(
self.settings.get_int('RESPONSE_ACTIVE_SIZE_LIMIT'))
self.downloader = Downloader(self.settings, self.request_queue,
self.response_queue, clock=self.clock)
# initialize extensions
self.extensions = ExtensionManager(self)
# initialize downloader pipeline
self.pipeline = PipelineManager(self)
self.initialized = True
# now that everything is ready, set the spider's engine
self.spider.set_engine(self)
def crawl_start_requests(self):
# process start requests from spider
try:
requests = self.spider.start_requests()
for req in arg_to_iter(requests):
self.download(req)
except:
log.err(Failure(), 'Error when processing start requests.')
def start(self):
assert self.initialized, 'Engine is not initialized. Call `setup()` to initialize it.'
self.start_time = time()
self.running = True
self.signals.send(signal=signals.engine_started)
self.processing.schedule(self.QUEUE_CHECK_FREQUENCY)
def stop(self, reason=''):
assert self.running, 'Engine is not running.'
self.running = False
def _stop(_):
self.processing.cancel()
self.downloader.close()
self.request_queue.close()
self.response_queue.close()
log.msg(format='Engine stopped (%(reason)s)', reason=reason)
self.signals.send(signal=signals.engine_stopped, reason=reason)
self.stats.dump_stats()
dfd = defer_succeed(reason, clock=self.clock)
dfd.addBoth(_stop)
return dfd
def pause(self):
self.paused = True
def unpause(self):
self.paused = False
def download(self, request):
'''"Download" the given request. First pass it through the downloader
pipeline.
- if the request is received, push it to `request_queue`
- if the response is received , push it to `response_queue`
'''
def _success(request_or_response):
if isinstance(request_or_response, Request):
self.signals.send(signal=signals.request_received,
request=request_or_response)
if self.running:
self.request_queue.push(request_or_response.priority,
request_or_response)
elif isinstance(request_or_response, Response):
request_or_response.request = request
if self.running:
self.response_queue.push(request_or_response)
def _failure(failure):
failure.request = request
dfd = defer_fail(failure, clock=self.clock)
dfd.addBoth(self._handle_pipeline_result)
dfd.addBoth(self._finalize_download)
return dfd
self.pending_requests += 1
d = defer_succeed(request, clock=self.clock)
d.addCallback(self.pipeline.process_request)
d.addCallbacks(_success, _failure)
return d
def is_idle(self):
return self.pending_requests == 0 and len(self.response_queue) == 0
def _process_queue(self):
if not self.running:
return
elif self.paused:
self.processing.schedule(self.PAUSED_CHECK_FREQUENCY)
elif self.response_queue:
response = self.response_queue.pop()
if isinstance(response, Response):
self.signals.send(signal=signals.response_downloaded,
response=response)
dfd = defer_result(response, clock=self.clock)
dfd.addBoth(self.pipeline.process_response)
dfd.addBoth(self._handle_pipeline_result)
dfd.addBoth(self._finalize_download)
dfd.addBoth(lambda _: self.processing.schedule(0))
elif self.is_idle():
# send `spider_idle` signal
res = self.signals.send(signal=signals.spider_idle,
dont_log=DontStopEngine)
dont_stop = any(isinstance(x, Failure) and
isinstance(x.value, DontStopEngine)
for _, x in res)
# more requests have been scheduled
if not self.is_idle():
self.processing.schedule(0)
# slow down a little, but still run
elif dont_stop or not self.stop_if_idle:
self.processing.schedule(self.IDLE_CHECK_FREQUENCY)
else:
self.stop('finished')
else:
self.processing.schedule(self.QUEUE_CHECK_FREQUENCY)
def _finalize_download(self, _):
self.pending_requests -= 1
def _handle_pipeline_result(self, result):
if result is None:
pass
elif isinstance(result, Request):
self.download(result)
else:
assert isinstance(result, (Response, Failure))
request = result.request
if isinstance(result, Response):
flags = ' %s' % result.flags if result.flags else ''
log.msg(format='Crawled %(url)s [%(status)s]%(flags)s',
level=log.DEBUG, url=result.url, status=result.status,
flags=flags)
self.signals.send(signal=signals.response_received,
response=result)
else:
self.signals.send(signal=signals.failure_received,
failure=result)
dfd = defer_result(result, clock=self.clock)
dfd.addCallbacks(request.callback or self.spider.parse,
request.errback)
dfd.addCallbacks(
self._handle_spider_output,
self._handle_spider_error,
callbackKeywords={'request': request},
errbackKeywords={'request': request})
return dfd
def _handle_spider_output(self, result, request):
result = arg_to_iter(result)
for request in result:
assert isinstance(request, Request), \
'spider must return None, request or iterable of requests'
self.download(request)
def _handle_spider_error(self, failure, request):
error = failure.value
if isinstance(error, StopEngine):
self.stop(error.reason)
return
# set `request` in a case the error was raised inside the spider
failure.request = request
self.signals.send(signal=signals.spider_error, failure=failure)
if not getattr(failure.value, 'quiet', False):
log.err(failure, 'Error when downloading %s' % request)
def __str__(self):
return '<%s at 0x%0x>' % (type(self).__name__, id(self))
__repr__ = __str__
def setUp(self):
self.handlers_called = set()
txlog.addObserver(self._log_received)
self.manager = SignalManager()
class SignalManagerTest(unittest.TestCase):
def setUp(self):
self.handlers_called = set()
txlog.addObserver(self._log_received)
self.manager = SignalManager()
def tearDown(self):
txlog.removeObserver(self._log_received)
self.flushLoggedErrors()
def _log_received(self, event):
self.handlers_called.add(self._log_received)
self.assertIn('error_handler', event['message'][0])
self.assertEqual(event['logLevel'], log.ERROR)
def _error_handler(self, arg):
self.handlers_called.add(self._error_handler)
a = 1 / 0
def _ok_handler(self, arg):
self.handlers_called.add(self._ok_handler)
self.assertEqual(arg, 'test')
return 'OK'
def _test(self, ok_handler, error_handler, get_result):
dispatcher.connect(error_handler, signal=test_signal)
dispatcher.connect(ok_handler, signal=test_signal)
result = yield defer.maybeDeferred(get_result, test_signal, arg='test')
self.assertIn(error_handler, self.handlers_called)
self.assertIn(ok_handler, self.handlers_called)
self.assertIn(self._log_received, self.handlers_called)
self.assertEqual(result[0][0], error_handler)
self.assertIsInstance(result[0][1], Failure)
self.assertEqual(result[1], (self.ok_handler, 'OK'))
dispatcher.disconnect(error_handler, signal=test_signal)
dispatcher.disconnect(ok_handler, signal=test_signal)
def test_send(self):
self._test(self._ok_handler, self._error_handler, self.manager.send)
def test_send_deferred(self):
self._test(self._ok_handler, self._error_handler,
self.manager.send_deferred)
def test_send_deffered2(self):
def ok_handler(arg):
self.handlers_called.add(ok_handler)
self.assertEqual(arg, 'test')
d = defer.Deferred()
reactor.callLater(0, d.callback, 'OK')
return d
self._test(ok_handler, self._error_handler, self.manager.send_deferred)
def test_error_logged_if_deferred_not_supported(self):
test_handler = lambda: defer.Deferred()
log_events = []
txlog.addObserver(log_events.append)
dispatcher.connect(test_handler, test_signal)
self.manager.send(test_signal)
self.failUnless(log_events)
self.failUnless(
'Cannot return deferreds from signal handler' in str(log_events))
txlog.removeObserver(log_events.append)
dispatcher.disconnect(test_handler, test_signal)
class Engine(object):
'''
WARNING: don't stop() and start() engine. Use pause() and unpause(),
instead.
'''
# how many seconds to wait between the checks of response_queue
QUEUE_CHECK_FREQUENCY = 0.1
# how often to check is still paused
PAUSED_CHECK_FREQUENCY = 5
# how often to check if being idle
IDLE_CHECK_FREQUENCY = 5
def __init__(self, settings, project, command_invoked='', clock=None):
'''Constructor of Engine should be very lightweight, so that things
can be easily unittested. For any more complicated initialization
use `setup()`.
'''
self.settings = settings
self.project = project
self.spiders = SpiderManager(settings)
self.stop_if_idle = True
self.initialized = False # True, when `setup()` has been called
# name of the command invoking the engine. E.g. `crawl`, `shell`, etc.
self.command_invoked = command_invoked
self.spider = None
self.pending_requests = 0
self.running = False
self.paused = False
# clock is used in unittests
self.clock = clock or reactor
self.processing = ScheduledCall(self._process_queue, clock=self.clock)
def set_spider(self, spider):
self.spider = spider
self.settings.spider_settings = spider.spider_settings()
def setup(self):
assert self.spider is not None, 'Spider is not set in Engine.'
# IMPORTANT: order of the following initializations is very important
# so please, think twice about any changes to it
# initialize logging
if self.settings.get_bool('LOG_ENABLED'):
log.start(self.settings['LOG_FILE'], self.settings['LOG_LEVEL'],
self.settings['LOG_STDOUT'],
self.settings['LOG_ENCODING'])
# initialize signals
self.signals = SignalManager(self)
#initialize stats
stats_cls = load_object(self.settings.get('STATS_CLASS'))
self.stats = stats_cls(self)
# initialize downloader
self.request_queue = PriorityQueue(lambda _: MemoryQueue())
self.response_queue = ResponseQueue(
self.settings.get_int('RESPONSE_ACTIVE_SIZE_LIMIT'))
self.downloader = Downloader(self.settings,
self.request_queue,
self.response_queue,
clock=self.clock)
# initialize extensions
self.extensions = ExtensionManager(self)
# initialize downloader pipeline
self.pipeline = PipelineManager(self)
self.initialized = True
# now that everything is ready, set the spider's engine
self.spider.set_engine(self)
def crawl_start_requests(self):
# process start requests from spider
try:
requests = self.spider.start_requests()
for req in arg_to_iter(requests):
self.download(req)
except:
log.err(Failure(), 'Error when processing start requests.')
def start(self):
assert self.initialized, 'Engine is not initialized. Call `setup()` to initialize it.'
self.start_time = time()
self.running = True
self.signals.send(signal=signals.engine_started)
self.processing.schedule(self.QUEUE_CHECK_FREQUENCY)
def stop(self, reason=''):
assert self.running, 'Engine is not running.'
self.running = False
def _stop(_):
self.processing.cancel()
self.downloader.close()
self.request_queue.close()
self.response_queue.close()
log.msg(format='Engine stopped (%(reason)s)', reason=reason)
self.signals.send(signal=signals.engine_stopped, reason=reason)
self.stats.dump_stats()
dfd = defer_succeed(reason, clock=self.clock)
dfd.addBoth(_stop)
return dfd
def pause(self):
self.paused = True
def unpause(self):
self.paused = False
def download(self, request):
'''"Download" the given request. First pass it through the downloader
pipeline.
- if the request is received, push it to `request_queue`
- if the response is received , push it to `response_queue`
'''
def _success(request_or_response):
if isinstance(request_or_response, Request):
self.signals.send(signal=signals.request_received,
request=request_or_response)
if self.running:
self.request_queue.push(request_or_response.priority,
request_or_response)
elif isinstance(request_or_response, Response):
request_or_response.request = request
if self.running:
self.response_queue.push(request_or_response)
def _failure(failure):
failure.request = request
dfd = defer_fail(failure, clock=self.clock)
dfd.addBoth(self._handle_pipeline_result)
dfd.addBoth(self._finalize_download)
return dfd
self.pending_requests += 1
d = defer_succeed(request, clock=self.clock)
d.addCallback(self.pipeline.process_request)
d.addCallbacks(_success, _failure)
return d
def is_idle(self):
return self.pending_requests == 0 and len(self.response_queue) == 0
def _process_queue(self):
if not self.running:
return
elif self.paused:
self.processing.schedule(self.PAUSED_CHECK_FREQUENCY)
elif self.response_queue:
response = self.response_queue.pop()
if isinstance(response, Response):
self.signals.send(signal=signals.response_downloaded,
response=response)
dfd = defer_result(response, clock=self.clock)
dfd.addBoth(self.pipeline.process_response)
dfd.addBoth(self._handle_pipeline_result)
dfd.addBoth(self._finalize_download)
dfd.addBoth(lambda _: self.processing.schedule(0))
elif self.is_idle():
# send `spider_idle` signal
res = self.signals.send(signal=signals.spider_idle,
dont_log=DontStopEngine)
dont_stop = any(
isinstance(x, Failure) and isinstance(x.value, DontStopEngine)
for _, x in res)
# more requests have been scheduled
if not self.is_idle():
self.processing.schedule(0)
# slow down a little, but still run
elif dont_stop or not self.stop_if_idle:
self.processing.schedule(self.IDLE_CHECK_FREQUENCY)
else:
self.stop('finished')
else:
self.processing.schedule(self.QUEUE_CHECK_FREQUENCY)
def _finalize_download(self, _):
self.pending_requests -= 1
def _handle_pipeline_result(self, result):
if result is None:
pass
elif isinstance(result, Request):
self.download(result)
else:
assert isinstance(result, (Response, Failure))
request = result.request
if isinstance(result, Response):
flags = ' %s' % result.flags if result.flags else ''
log.msg(format='Crawled %(url)s [%(status)s]%(flags)s',
level=log.DEBUG,
url=result.url,
status=result.status,
flags=flags)
self.signals.send(signal=signals.response_received,
response=result)
else:
self.signals.send(signal=signals.failure_received,
failure=result)
dfd = defer_result(result, clock=self.clock)
dfd.addCallbacks(request.callback or self.spider.parse,
request.errback)
dfd.addCallbacks(self._handle_spider_output,
self._handle_spider_error,
callbackKeywords={'request': request},
errbackKeywords={'request': request})
return dfd
def _handle_spider_output(self, result, request):
result = arg_to_iter(result)
for request in result:
assert isinstance(request, Request), \
'spider must return None, request or iterable of requests'
self.download(request)
def _handle_spider_error(self, failure, request):
error = failure.value
if isinstance(error, StopEngine):
self.stop(error.reason)
return
# set `request` in a case the error was raised inside the spider
failure.request = request
self.signals.send(signal=signals.spider_error, failure=failure)
if not getattr(failure.value, 'quiet', False):
log.err(failure, 'Error when downloading %s' % request)
def __str__(self):
return '<%s at 0x%0x>' % (type(self).__name__, id(self))
__repr__ = __str__
def setUp(self):
self.handlers_called = set()
txlog.addObserver(self._log_received)
self.manager = SignalManager()
class SignalManagerTest(unittest.TestCase):
def setUp(self):
self.handlers_called = set()
txlog.addObserver(self._log_received)
self.manager = SignalManager()
def tearDown(self):
txlog.removeObserver(self._log_received)
self.flushLoggedErrors()
def _log_received(self, event):
self.handlers_called.add(self._log_received)
self.assertIn('error_handler', event['message'][0])
self.assertEqual(event['logLevel'], log.ERROR)
def _error_handler(self, arg):
self.handlers_called.add(self._error_handler)
a = 1 / 0
def _ok_handler(self, arg):
self.handlers_called.add(self._ok_handler)
self.assertEqual(arg, 'test')
return 'OK'
def _test(self, ok_handler, error_handler, get_result):
dispatcher.connect(error_handler, signal=test_signal)
dispatcher.connect(ok_handler, signal=test_signal)
result = yield defer.maybeDeferred(get_result, test_signal, arg='test')
self.assertIn(error_handler, self.handlers_called)
self.assertIn(ok_handler, self.handlers_called)
self.assertIn(self._log_received, self.handlers_called)
self.assertEqual(result[0][0], error_handler)
self.assertIsInstance(result[0][1], Failure)
self.assertEqual(result[1], (self.ok_handler, 'OK'))
dispatcher.disconnect(error_handler, signal=test_signal)
dispatcher.disconnect(ok_handler, signal=test_signal)
def test_send(self):
self._test(self._ok_handler, self._error_handler, self.manager.send)
def test_send_deferred(self):
self._test(self._ok_handler, self._error_handler, self.manager.send_deferred)
def test_send_deffered2(self):
def ok_handler(arg):
self.handlers_called.add(ok_handler)
self.assertEqual(arg, 'test')
d = defer.Deferred()
reactor.callLater(0, d.callback, 'OK')
return d
self._test(ok_handler, self._error_handler, self.manager.send_deferred)
def test_error_logged_if_deferred_not_supported(self):
test_handler = lambda: defer.Deferred()
log_events = []
txlog.addObserver(log_events.append)
dispatcher.connect(test_handler, test_signal)
self.manager.send(test_signal)
self.failUnless(log_events)
self.failUnless('Cannot return deferreds from signal handler' in str(log_events))
txlog.removeObserver(log_events.append)
dispatcher.disconnect(test_handler, test_signal)