There are loads of use cases which require “all or nothing” processing. And there are a bunch of different strategies for accomplishing said result. Luckily for me, they’ve already been covered many times in tons of different blogs/books/articles. So for this post I’m just going to concentrate on a few of the strategies, and more specifically, how to do them with Apache Camel.
When out and about, I often get the question: “How do I setup HA (high availability) with Red Hat’s JBoss Fuse?”. People ask this question and they expect a simple, straightforward answer. And why shouldn’t they? The question is simple enough right? I could ask the same question about something like Tomcat and get a well documented answer involving little more than a loadbalancer. Unfortunately, the answer for Fuse is a bit more involved and usually starts with the annoying response of “it depends”.
Apache Camel is a pretty full-featured EIP implementation framework. It has several existing strategies for load-balancing right out of the box. Round Robin, Random, Sticky, Weighted Round Robin, Weighted Random,… the list goes on and on. But being that it’s a very well written and pluggable framework, it also gives you the ability to drop in your own custom strategies should you find that none of the existing ones meet your specific needs. So for this post, I created a custom Camel Load Balancer implementation utilizing an Infinispan cache to dynamically discover and load-balance between destination endpoints.
In many environments, it is common to ingest data as a batch process. This is usually accomplished by polling a directory (or FTP server) for files. The issue is that polling for files is a one-way communication. So if you get a file that you can’t parse (or one that is invalid for any other reason), you have no way of communicating that back to the original sender. How do you handle the error? You likely can’t just drop the data on the floor. That really only leaves one option and that is to correct the data and re-ingest it.
This guide demonstrates step-by-step how to create a sample Camel project in JBoss Developer Studio (JBDS) using the Maven archetypes that come out of the box. Specifically, we’ll be creating a contract-first based web services java project. We’ll then convert that project to a WAR file so that it can be deployed to JBoss EAP. Finally, we’ll deploy the project and verify that it is running.
