After testing it, it seemed like a lot of fun. Another of my projects was to learn Docker (scorching hot right now).
So I thought "Why not combine them?", little did I know that I was in for a world of Internet-searching, documentation exploring and more.
So first some more Info on Mule and Docker:
Mule ESB
Is kind of an adapter between services. It's message-based and has a lot of functionality already done.
Ex: Say you have a Java site that needs paypal. Mule can sit between, take the request by JMS, HTTP and more and pipe it to paypal and then back again. Maybe you want a facebook post for every 1000 visitor? No problem.
Why do this when you can code it your self? One of the reasons is that you can use much of the code again, you can separate some of the work to this Mule server or you can do a microservice style and have Mule be the glue between them all.
Docker (Docker.io)
Docker is a way to make Linux Containers (LXC) manageable and share-able. It's a technology for making small VM's where you can isolate you app.
Why? Say that your a developer. Your app works in your developer environment. But that's not always the case for the production environment.
What if you could have a environment under development and just ship the whole environment? That's what you do with Docker.
It's also a good subject if you want have microservice's, every service can have its own Docker Container.
And it's scalable, you can have servers with CoreOS (made for running in HUGE clusters, we're talking Google-size) and run your Docker Container.
Cause that's one of the best perks, your Docker Container runs ANYWHERE where there is a Docker Engine. You can develop under Windows and Mac with boot2docker via Virtualbox and then Deploy to a real Linux Server running Docker Engine.
And people share many of their Docker Containers via buildfiles (DockerFile). You can have your own private registry of Images or use the Central DockerHub.
My Problem
So there is a couple of people that have done Docker Containers for Mule Server.
And I could not get this to work!
I was a rookie at Docker so I blamed my lack of knowledge.
I followed the guide and it would not work.
The regular Mule Server and my test app work perfectly.
The Docker version blocked the right ports, but it would not give me a response.
I scratched my head...
Spinning up a Wildfly server in docker was 2 commands and it worked perfectly.
So I compared the DockerFiles, but nothing looked weird. Was there something special with Mule?
But why? The creator seemed to get it to work without problem.
After that I found a solution!... Or so I thought. I was able to publish the port so I could run and get a response...from localhost but not from a remote computer.
But wildfly worked with the remote computer, what was the difference???
Frankly I thought I was missing a puzzle piece with Docker, like firewall, config or something.
After 2 weeks of leaving and coming back to it (Googled some on breaks at works, coming up with new ideas what it could be) I finally found the answer.
After being really frustrated I started to really look at the test app and compare it to the Docker Container Creators test app.
My app said that localhost should run the http start-point, the other app said 0.0.0.0....
OF COURSE! So I was looking at the wrong place!
I thought I made the simplest test app ever, a little hello world, but I succeeded in not doing it correctly.
After changing it to 0.0.0.0 it worked flawlessly. So simple that it's extra hard to find.
But on the up side I learned A LOT about Docker and how to use it.
So I can recommend Docker and Mule, Docker is not as hard as some think, just know what your putting in it before blaming Docker.
Code ahoy!
