January 2, 2010

Cargo Maven Plugin: Not Made for JBoss


Well, actually this blog was supposed to be about Java in general and all the ups and downs I experience during my daily work. However, I've not been doing much other than Maven configuration and build management lately, so here is another Maven related post. Sorry folks.

As already shown in this post, I have been doing integration tests with JBoss by using the Cargo Maven plugin to start the JBoss locally and deploy the application to it. This all works quite as soon as you have figured out how to configure Cargo for JBoss.

But Remotely Now!

Now, the next step is to deploy our EAR file which is generated during nightly build to a running JBoss instance on a separate computer. This is different because no JBoss configuration has to be created locally and no JBoss has to be started. Instead, the EAR file must be transferred to a remote server where JBoss is already running, and JBoss must be persuaded to deploy this file.

That sounds feasible, and I've done exactly this before for other servers like Tomcat, so I did not expect any issue here. However, I was wrong.

Itch #1

First trouble was caused by my lack of knowledge regarding JBoss. With standard installation, you are not able to connect to the server remotely and all the services are bound to localhost only (see here or here). This is intentionally, to prevent unprotected installations appearing all over the net. You have to pass the option -b when starting JBoss to allow remote connections to the services, but take care to secure your JBoss accordingly!

Itch #2

Okay, after this has been configured, I tried to use Cargo to deploy my EAR file to JBoss. This is the configuration I ended up with:

<!-- *** Cargo plugin: deploy the application to running JBoss *** -->
<!-- Container configuration -->
<!-- Configuration to use with the Container -->
<!-- Deployer configuration -->


However, I always got this error message:

[INFO] Failed to deploy to [http://...]
Server returned HTTP response code: 500 for URL: ...

The configuration seems to be correct, so what is the problem?

After asking Google, I realized that Cargo is not able to transfer a file to JBoss! Instead, it requires the deployable to be deployed to be present on the server filesystem (see here). This is obviously caused by the JBoss JMX deployer which is used by Cargo, but actually you don't care who is to blame – you just want it to work. The name "Cargo" implies the parcel is transferred to its destination, right? Also note that this issue is dated from Sep 2006, so there has been some time to fix it in either way.

What Can We Do?

Well, there are probably not many options. Since current version of Cargo is not able to transfer the file to the server, you'd have to do this on your own. The location given in our Cargo configuration above actually is the path on the JBoss server. So, when the file exists locally on the JBoss server, Cargo should be able to deploy it successfully.

For transferring the file to JBoss server, we could use the maven-dependency-plugin, a quite useful plugin for all kind of analyzing, copying or unpacking artifacts. We configure it to run in pre-integration-test phase and to copy the EAR file (produced by this POM) to some temp directory on the JBoss server:


The property ${publish.tempdir} can be anything on the JBoss server (which must be available in the network!) and is exactly what has to be used for the value of location element in Cargo configuration.

Another option would be to use the hot-deploy directory of JBoss as outputDirectory for the dependency plugin, and hence rely on hot deployment of JBoss instead of Cargo and JBoss JMX deployer. This way, we could get rid of Cargo configuration and cleanup the POM a bit, but in the end it seemed a bit less clean to me... your mileage may vary.

So, as always, in the end we got it to work, but not without unforeseen pain. When will Cargo be fixed to get the EAR file to JBoss server? Who knows.


2010/01/22: Note that the dependency plugin must be bound after the install phase so that the artifact has been copied at least to your local Maven repository. As a consequence, the Cargo plugin must be run in deploy phase, which is actually a good choice anyways. I have changed this in my code above.

1 comment: