Posted on : 19-03-2011 | By : Paolo Iannelli | In : Monitoring, Python, Software Development, System Administration
Tags: API, Datacenter, How To, HowTo, Message Broker, Monitoring, Python, RabbitMQ, REST, Sensor, Temperature
What is RabbitMQ?
Shortly, RabbitMQ is a message broker that allows you to exchange messages between heterogeneous applications.
You can find more information at http://www.rabbitmq.com.
What you do with it is just sending messages (that can be any kind of information : binary / plain-text, doesn’t matter!) to a so-called “queue”. Any client attached to this queue will retrieve the messages.
Cool ! But why RabbitMQ and not an API ?
Well, choosing between API and messaging might be hard if you are not familiar with messaging services, but I will show you just an example where RabbitMQ is really powerful compared to a simple API.
Imagine you have 4 temperature sensors in 4 different racks. Each of these sensors are attached to a server connected to the internet. Your goal is to read the temperature of every rack and display it.
What you can do is having an API in those servers that just output the value read from the sensor. Then, from the client, you request via a REST API this value.
Alternatively you can have a centralized REST API and force each server to run a script every X seconds to update the value with a PUT request to this REST service.
So, everyone agree that the second solution would work pretty nicely. In fact, is true.
But, what if tomorrow we want to organize those “temperature servers” by location, representing for instance a datacenter in USA and one in Canada?
I have no doubt that the first thing will come in your mind is : I change the API and put a “location” field somewhere so I know from where the data comes from.
Probably the change wouldn’t take so much effort but still you have to modify an API to achieve the goal.