def testEndMessageCloseReader(self, mocked_remove, mocked_filename):
reader = mock.MagicMock()
oc.end_message({
'some': 'content',
'contents_reader': reader
}, 'unique name')
reader.close.assert_called_once()
def testEndMessageRemoveFailed(self, mocked_print, mocked_remove, mocked_filename):
mocked_remove.side_effect = Exception
reader = mock.MagicMock()
oc.end_message({'some': 'content', 'contents_reader': reader}, 'unique name')
reader.close.assert_called_once()
mocked_print.assert_called_once()
self.assertTrue(mocked_print.call_args[0][0].startswith('Remove failed'))
def testEndMessage(self, mocked_remove, mocked_filename):
# End message without any contents_ref does nothing
self.assertEqual(oc.end_message({}, {}), None)
self.assertFalse(mocked_filename.called)
self.assertFalse(mocked_remove.called)
# End message with contents_ref gets the filename and removes it
self.assertEqual(oc.end_message({}, "x"), None)
mocked_filename.assert_called_with("x", "message_broker")
mocked_remove.assert_called_with("filename")
def run_message_handler():
offload_id = None
result = None
msg = None
try:
# Try to get the message, parse any json contents and retrieve any offloaded contents
# Include any queue specific parameters
params = {**self._params, **self._params.get(queue, {})}
msg, offload_id = get_message_from_body(body, params)
# Try to handle the message
result = message_handler(self, basic_deliver.exchange,
queue, basic_deliver.routing_key,
msg)
except Exception as e:
# Print error message, the message that caused the error and a short stacktrace
stacktrace = traceback.format_exc(limit=-10)
print(
f"Message handling has failed: {str(e)}, message: {str(body)}",
stacktrace)
if basic_deliver.redelivered:
# When a message is redelivered then remove the message from the queue
print(
"Message handling has failed on second try, removing message"
)
else:
# Fatal fail program on first try
print(
"Message handling has failed, terminating program")
os._exit(os.EX_TEMPFAIL)
if msg is not None:
# run fail-safe method to end the message
end_message(msg, offload_id)
if result is not False:
# Default is to acknowledge message
# Only on an explicit return value of False the message keeps unacked.
channel.basic_ack(basic_deliver.delivery_tag)
else:
# This prevents a task queue from executing the same message twice due to concurrency
# The original message should be handled
print("Message not acknowlegded, discarding message")
channel.basic_nack(basic_deliver.delivery_tag,
requeue=False)
def run_message_handler():
offload_id = None
result = None
msg = None
try:
# Try to get the message, parse any json contents and retrieve any offloaded contents
msg, offload_id = get_message_from_body()
# Try to handle the message
result = message_handler(self, basic_deliver.exchange, queue, basic_deliver.routing_key, msg)
except Exception as e:
# Print error message, the message that caused the error and a short stacktrace
stacktrace = traceback.format_exc(limit=-5)
print(f"Message handling has failed: {str(e)}, message: {str(body)}", stacktrace)
if msg is not None:
# run fail-safe method to end the message
end_message(msg, offload_id)
if result is not False:
# Default is to acknowledge message
# Only on an explicit return value of False the message keeps unacked.
channel.basic_ack(basic_deliver.delivery_tag)
