Comments (3)
Thanks for this heads-up. But I don't see where anything would run in a thread different from the main thread without explicitly telling the reactor to do so. Where do we leave the main thread in the first place? And if so, how do you suggest to fix this?
from stompest.
You are right, only by telling the reactor to do run in another thread can that happen.
I provide an example.
twisted_test_consumer.txt
twisted_test_producer.txt
Just change the suffix of the files to be .py and run them.
As you will see, the consumer logs "Sending ACK frame..." in a thread different from main thread.
In my message handler "consume", I tell the reactor to run "callback_func" in another thread because somehow it runs for a while and I hope multiple messages be processed in parallel. As a result, the rest of the "onMessage" function(stompest/src/async/stompest/async/listener.py line 207) will also run in that thread due to the mechanism of Deferred and reactor.
As we can't let ack run in main thread again, I suggest a lock be acquired at before telling twisted transport to write, just use lock in the StompProtocol object
in init:
self._lock = threading.RLock()
and do the following
with self._lock:
self.transport.write(binaryType(frame))
(stompest/src/async/stompest/async/protocol.py line 48)
I think this resolves the problem
from stompest.
Synchronizing the access to the transport level is exactly what you shouldn't do in an asynchronous (sic!) setting, so your suggested solution is invalid.
Looking at your message handler
@defer.inlineCallbacks
def consume(self, client, frame):
d = defer.Deferred()
d.addCallback(longRunningCalculation)
reactor.callInThread(d.callback, "result 1")
yield d
You are doing something very wicked, namely calling a callback from another thread, so you yield
from one (the main) thread and send
from another, which messes up the coroutine and imho breaks the reactor (which must remain single-threaded) altogether. If you do it this way (untested), it should work:
from twisted.internet import threads
[...]
@defer.inlineCallbacks
def consume(self, client, frame):
result = yield threads.deferToThread(longRunningCalculation)
logging.debug("In the main thread: %s", result)
from stompest.
Related Issues (20)
- ipv6 support HOT 1
- stompest consumer is slow for activemq HOT 4
- How to config exclusive=true ? HOT 4
- Messages not recieving after queue is idle for some time HOT 1
- failover option 'startupMaxReconnectAttempts' default value should be -1
- Support for asyncio HOT 2
- Asynch examples on ActiveMQ - Artemis HOT 1
- support SSL client auth in stompest.async HOT 5
- Exception <class 'select.error'>: (4, 'Interrupted system call') after upgrading stompest HOT 4
- stompest.async will be unusable on python 3.7+ HOT 10
- receiveFrame does not accept a timeout parameter HOT 3
- How to dynamically increase the number of consumers HOT 1
- Invalid SUBSCRIBE format HOT 2
- StompFrame and StompHeartBeat __str__ method returns bytes in Python 3
- failover doesn't seem to be working HOT 1
- how to get JMSXDeliveryCount in the stomp frame HOT 1
- When use version=1.2, the consumer stop to connect on topic
- collections.MutableMapping is not available in Python 3.10 HOT 7
- STOMP over websocket
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from stompest.