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--- comb:rabbitmq [2014/07/15 09:25]
alfred [Commands]
+++ comb:rabbitmq [2020/05/09 09:25] (actual)
@@ Línea 23: / Línea 23: @@
 <code>
 $ sudo rabbitmqctl list_queues name messages_ready messages_unacknowledged
+</code>
+=== Listing exchanges ===
+<code>
+$ sudo rabbitmqctl list_exchanges
+</code>
+=== List bindings ===
+<code>
+$ sudo rabbitmqctl list_bindings
+</code>
+==== Concepts ====
+=== Exchanges ===
+A producer can only send messages to an exchange. The exchange receives messages from producers and it pushes them to queues.
+  * direct
+  * topic
+  * headers
+  * fanout: it broadcasts all the messages it receives to all the queues it knows.
+Some amq.* exchanges and the default (unnamed) exchange are created by default, we identify the default exchange by the empty string.
+To declare an exchange it's used:
+<code python>
+channel.exchange_declare(exchange='logs', type='fanout')
+</code>
+=== Bindings ===
+The relationship between exchange and a queue is called a binding.
+<code python>
+channel.queue_bind(exchange='logs', queue=result.method.queue)
+</code>
+=== Temporary queues ===
+Whe we want to hear about all messages and not just a subset of them. We need to connect to Rabbit with an empty queue. To do it we could let the server choose a random queue name for us. We can do this by not supplying the queue parameter to queue_declare:
+<code python>
+result = channel.queue_declare()
+</code>
+Also we need that once we disconnect the consumer the queue should be deleted. There's an exclusive flag for that:
+<code python>
+result = channel.queue_declare(exclusive=True)
 </code>
 ===== Use =====
@@ Línea 61: / Línea 101: @@
 </code>
   * ''no_ack'' means //no acknowledgement// messages.
+  * We can tell to Rabbit that do not deliver more than a message to a worker with ''prefetch_count=1'' into the worker channel.
-==== Message acknowledgment ====
+==== Message acknowledgment and persistent queues ====
   * Message acknoledgement is done after connection dies.
+    * Message acknoledgement is active by default, it is defined by ''no_ack'' parameter.
+  * Persistent messages and queues are those which remain in the computer even if the computer or rabbit crash.
+    * They are activated marking the queue as durable and the delivery_mode property with a value 2.
+<code python>
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+import pika
+import time
+def callback(ch, method, properties, body):
+    print " [x] Received %r" % (body,)
+    time.sleep(body.count('.'))
+    print " [x] Done"
+    ch.basic_ack(delivery_tag=method.delivery_tag)
+connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
+channel = connection.channel()
+channel.queue_declare(queue='task_queue', durable=True)
+print ' [*] Waiting for messages. To exit press CTRL+C'
+channel.basic_qos(prefetch_count=1)
+channel.basic_consume(callback, queue='task_queue')
+channel.start_consuming()
+</code>
+<code python>
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+import pika
+import sys
+connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
+channel = connection.channel()
+channel.queue_declare(queue='task_queue', durable=True)
+message = ' '.join(sys.argv[1:]) or "Hello World!"
+channel.basic_publish(exchange='',
+                      routing_key='task_queue',
+                      body=message,
+                      properties=pika.BasicProperties(delivery_mode=2,))
+print " [x] Sent %r" % (message,)
+connection.close()
+</code>
+==== Publish\Subscriber ====
+<code python>
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+import pika
+def callback(ch, method, properties, body):
+    print " [x] %r" % (body,)
+connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
+channel = connection.channel()
+channel.exchange_declare(exchange='logs', type='fanout')
+result = channel.queue_declare(exclusive=True)
+queue_name = result.method.queue
+channel.queue_bind(exchange='logs', queue=queue_name)
+print ' [*] Waiting for logs. To exit press CTRL+C'
+channel.basic_consume(callback, queue=queue_name, no_ack=True)
+channel.start_consuming()
+</code>
+<code python>
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+import pika
+import sys
+connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
+channel = connection.channel()
+channel.exchange_declare(exchange='logs', type='fanout')
+message = ' '.join(sys.argv[1:]) or "info: Hello World!"
+channel.basic_publish(exchange='logs', routing_key='', body=message)
+print " [x] Sent %r" % (message,)
+connection.close()
+</code>
+===== Others =====
+==== Plugins ====
+=== Management ===
+<code>
+$ rabbitmq-plugins enable rabbitmq_management
+</code>
+Will enable the web management server. You'll find at: [[http://server:15672]] (p.eg. [[http://127.0.0.1:15672/]]). Username ''guest'' and password ''guest'' is the authentication by default.
+Para añadir usuarios:
+  - you need to create a user for any vhost on that system (here I use default vhost "/")
+<code>
+$ rabbitmqctl add_user yourName yourPass
+</code>
+  - Set the permissions for that user for default vhost
+<code>
+$ rabbitmqctl set_permissions -p / yourName ".*" ".*" ".*"
+</code>
+  - Set the administrator tag for this user (to enable him access the management pluggin)
+<code>
+$ rabbitmqctl set_user_tags yourName administrator
+</code>
+==== Notes ====
+=== Reset RabbitMQ ===
+... Queues, config, everything!
+<code>
+$ rabbitmqctl stop_app
+$ rabbitmqctl reset
+$ rabbitmqctl start_app
+</code>

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