Archive for the 'HowTo' Category
March 1, 2021
Diana Parra Corbacho
We have been constantly improving the monitoring capabilities that are built into RabbitMQ since shipping native Prometheus support in 3.8.0. Monitoring the broker and its clients is critically important for detecting issues before they affect the rest of the environment and, eventually, the end users.
RabbitMQ 3.8.10 exposes client authentication attempts metrics via both the Prometheus endpoint and the HTTP API.
October 30, 2014
“How much memory is my queue using?” That’s an easy question to ask, and a somewhat more complicated one to answer. RabbitMQ 3.4 gives you a clearer view of how queues use memory. This blog post talks a bit about that, and also explains queue memory use in general.
April 2, 2014
What? Another “breaking things” post? Well, yes, but hopefully this should be less to deal with than the previous one. But there are enough slightly incompatible changes in RabbitMQ 3.3.0 that it’s worth listing them here.
February 19, 2014
In this blog post we are going to address the problem of controlling the access to a particular resource in a distributed system.
The technique for solving this problem is well know in computer science, it’s called Semaphore and it was invented by Dijkstra in 1965
in his paper called “Cooperating Sequential Processes”. We are going to see how to implement it using AMQP’s building blocks, like consumers,
producers and queues.
January 23, 2014
Different services in our architecture will require a certain amount of resources for operation, whether these resources are CPUs, RAM or disk space, we need to make sure we have enough of them. If we don’t put limits on how many resources our servers are going to use, at some point we will be in trouble. This happens with your database if it runs out of file system space, your media storage if you fill it with images and never move them somewhere else, or your JVM if it runs out of RAM. Even your back up solution will be a problem if you don’t have a policy for expiring/deleting old backups. Well, queues are no exception. We have to make sure that our application won’t allow the queues to grow for ever. We need to have some strategy in place to delete/evict/migrate old messages.
December 16, 2013
With RabbitMQ 3.2.0 we introduced Consumer Priorities which not surprisingly allows us to set priorities for our consumers. This provides us with a bit of control over how RabbitMQ will deliver messages to consumers in order to obtain a different kind of scheduling that might be beneficial for our application.
When would you want to use Consumer Priorities in your code?
October 23, 2013
So we added support for federated queues in RabbitMQ 3.2.0. This blog post explains what they’re for and how to use them.
June 3, 2013
RabbitMQ is a very extensible message broker, allowing users to extend the server’s functionality by writing plugins. Many of the broker features are even shipped as plugins that come by default with the broker installation: the Management Plugin, or STOMP support, to name just a couple. While that’s pretty cool, the fact that plugins must be written in Erlang is sometimes a challenge. I decided to see if it was possible to write plugins in another language that targeted the Erlang Virtual Machine (EVM), and in this post I’ll share my progress.
November 19, 2012
RabbitMQ includes a bunch of cool new features. But in order to implement some of them we needed to change some things. So in this blog post I’m going to list some of those things in case you need to do anything about them.
September 24, 2011
One of the problems we face at the RabbitMQ HQ is that whilst we may
know lots about how the broker works, we don’t tend to have a large
pool of experience of designing applications that use RabbitMQ and
which need to work reliably, unattended, for long periods of time. We
spend a lot of time answering questions on the mailing list, and we do
consultancy work here and there, but in some cases it’s as a result of
being contacted by users building applications that we’re really made
to think about long-term behaviour of RabbitMQ. Recently, we’ve been
prompted to think long and hard about the basic performance of queues,
and this has lead to some realisations about provisioning Rabbits.
August 16, 2011
Recently we launched a RabbitMQ service for Cloud Foundry, making it simple to spin up a message broker to use with your apps on Cloud Foundry. There are tutorials online for using it with Ruby on Rails and with Java apps using Spring. Here we are going to look at using the RabbitMQ service with Node.JS apps.
June 22, 2011
Note: this blog post talks about the federation plugin preview that was released for RabbitMQ 2.5.0. If you’re using 2.6.0 or later, federation is part of the main release; get it the same way you would any other plugin.
Another day, another new plugin release 😃 Today it’s federation. If you want to skip this post and just download the plugin, go here. The detailed instructions are here.
The high level goal of federation is to scale out publish / subscribe messaging across WANs and administrative domains.
To do this we introduce the concept of the federation exchange. A federation exchange acts like a normal exchange of a given type (it can emulate the routing logic of any installed exchange type), but also knows how to connect to upstream exchanges (which might in turn themselves be federation exchanges).
February 7, 2011
RabbitMQ 2.3.1 introduces a couple of new plugin mechanisms, allowing you much more control over how users authenticate themselves against Rabbit, and how we determine what they are authorised to do. There are three questions of concern here:
- How does the client prove its identity over the wire?
- Where do users and authentication information (e.g. password hashes) live?
- Where does permission information live?
Question 1 is answered in the case of AMQP by SASL - a simple protocol for pluggable authentication mechanisms that is embedded within AMQP (and various other protocols). SASL lets a client and a server negotiate and use an authentication mechanism, without the “outer” protocol having to know any of the details about how authentication works.
SASL offers a number of “mechanisms”. Since the beginning, RabbitMQ has supported the PLAIN mechanism, which basically consists of sending a username and password over the wire in plaintext (of course possibly the whole connection might be protected by SSL). It’s also supported the variant AMQPLAIN mechanism (which is conceptually identical to PLAIN but slightly easier to implement if you have an AMQP codec lying around). RabbitMQ 2.3.1 adds a plugin system allowing you to add or configure more mechanisms, and we’ve written an example plugin which implements the SASL EXTERNAL mechanism.
November 12, 2010
Among the more impressive of these libraries is Socket.
October 2, 2010
I am setting up my old MacBook, reclaimed from my housemate, to be usable for the programmings.