[rabbitmq-discuss] Help with topics not working from Pika
Darren Govoni
darren at ontrenet.com
Wed Sep 4 13:57:54 BST 2013
Hi,
I have a bizarre situation with topics working and not working in
pika. Pretty sure this is a bug of some kind.
I adapted the topic pub/sub example slightly and found that it doesn't
act like a topic anymore, but a direct queue.
Clearly these two files establish a topic exchange and bind a queue to
it and should thus behave like a topic,
but it behaves like a direct queue only.
Step 1. In one window run "python receive_1.py _workflow"
Step 2. In another window run "python receive_1.py _workflow"
Step 3. In a third window run "python emit_1.py _workflow"
Only one of the receivers gets the message. If you continue to run emit_1.py
it distributes between your two receivers.
Can I not declare a queue name and bind it to a topic exchange? It seems
not.
Here are the files:
emit_1.py
============================================
#!/usr/bin/env python
import pika
import sys
connection = pika.BlockingConnection(pika.ConnectionParameters(
host='localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='workflow',
type='topic')
routing_key = sys.argv[1] if len(sys.argv) > 1 else 'anonymous.info'
message = ' '.join(sys.argv[2:]) or 'Hello World!'
channel.basic_publish(exchange='workflow',
routing_key=routing_key,
body=message)
print " [x] Sent %r:%r" % (routing_key, message)
connection.close()
and receive_1.py
============================================
#!/usr/bin/env python
import pika
import sys
connection = pika.BlockingConnection(pika.ConnectionParameters(
host='localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='workflow',
type='topic')
result = channel.queue_declare(queue='workflow')
queue_name = result.method.queue
binding_keys = sys.argv[1:]
if not binding_keys:
print >> sys.stderr, "Usage: %s [binding_key]..." % (sys.argv[0],)
sys.exit(1)
for binding_key in binding_keys:
print "binding_key ",binding_key
channel.queue_bind(exchange='workflow',
queue=queue_name,
routing_key=binding_key)
print ' [*] Waiting for logs. To exit press CTRL+C'
def callback(ch, method, properties, body):
print " [x] %r:%r" % (method.routing_key, body,)
channel.basic_consume(callback,
queue=queue_name,
no_ack=True)
channel.start_consuming()
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