message-queue - w3toppers.com

Getting number of messages in a RabbitMQ queue

Using pika: import pika pika_conn_params = pika.ConnectionParameters( host=”localhost”, port=5672, credentials=pika.credentials.PlainCredentials(‘guest’, ‘guest’), ) connection = pika.BlockingConnection(pika_conn_params) channel = connection.channel() queue = channel.queue_declare( queue=”your_queue”, durable=True, exclusive=False, auto_delete=False ) print(queue.method.message_count) Using PyRabbit: from pyrabbit.api import Client cl = Client(‘localhost:55672’, ‘guest’, ‘guest’) cl.get_messages(‘example_vhost’, ‘example_queue’)[0][‘message_count’] Using HTTP Syntax: curl -i -u user:password http://localhost:15672/api/queues/vhost/queue Example: curl -i -u guest:guest http://localhost:15672/api/queues/%2f/celery Note: … Read more

Is there a performance difference between pooling connections or channels in rabbitmq?

I have found this on the rabbitmq website it is near the bottom so I have quoted the relevant part below. The tl;dr version is that you should have 1 connection per application and 1 channel per thread. Connections AMQP connections are typically long-lived. AMQP is an application level protocol that uses TCP for reliable … Read more

When to use RabbitMQ over Kafka? [closed]

RabbitMQ is a solid, general-purpose message broker that supports several protocols such as AMQP, MQTT, STOMP, etc. It can handle high throughput. A common use case for RabbitMQ is to handle background jobs or long-running task, such as file scanning, image scaling or PDF conversion. RabbitMQ is also used between microservices, where it serves as … Read more

What is the relationship between Looper, Handler and MessageQueue in Android?

A Looper is a message handling loop: it reads and processes items from a MessageQueue. The Looper class is usually used in conjunction with a HandlerThread (a subclass of Thread). A Handler is a utility class that facilitates interacting with a Looper—mainly by posting messages and Runnable objects to the thread’s MessageQueue. When a Handler … Read more

Using many consumers in SQS Queue

What is the best approach to guarantee that a message will be processed once? You’re asking for a guarantee – you won’t get one. You can reduce probability of a message being processed more than once to a very small amount, but you won’t get a guarantee. I’ll explain why, along with strategies for reducing … Read more

Cannot find the declaration of element ‘beans’

Try this, assuming you’re on Spring 3.1: <beans xmlns=”http://www.springframework.org/schema/beans” xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=” http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd”> Replace 3.1 on the last line with whatever major Spring version you use. Meaning: there is no 3.1.1 XSD even though there is a Spring version 3.1.1.

Real world use of JMS/message queues? [closed]

JMS (ActiveMQ is a JMS broker implementation) can be used as a mechanism to allow asynchronous request processing. You may wish to do this because the request take a long time to complete or because several parties may be interested in the actual request. Another reason for using it is to allow multiple clients (potentially … Read more

Why must SetWindowsHookEx be used with a windows message queue

The low-level hooks, WH_KEYBOARD_LL and WH_MOUSE_LL are different from all the other hooks. They don’t require a DLL to be injected into the target process. Instead, Windows calls your hook callback directly, inside your own process. To make that work, a message loop is required. There is no other mechanism for Windows to make callbacks … Read more

What exactly is a Node.js event loop tick?

Remember that while JavaScript is single-threaded, all of node’s I/O and calls to native APIs are either asynchronous (using platform-specific mechanisms), or run on a separate thread. (This is all handled through libuv.) So when there’s data available on a socket or a native API function has returned, we need a synchronized way to invoke … Read more

RabbitMQ – Message order of delivery

Well, let’s take a closer look at the scenario you are describing above. I think it’s important to paste the documentation immediately prior to the snippet in your question to provide context: Section 4.7 of the AMQP 0-9-1 core specification explains the conditions under which ordering is guaranteed: messages published in one channel, passing through … Read more