Using Jboss System Properties

So if I have a jboss application set up on different environments, is there an easy way for me to load environment specific properties on a per instance basis?

Yes there is, read on.

So normally, in most applications you might end up with some property values you’ll want to override based on the environment. For example, login credentials to some third party service, environment specific file locations, environment specific jnp servers, or properties that flag the application’s mode as test or production environments.

It’s generally a good idea for an application to have properties bundled within the deployable artifact so that during deployment you can avoid running into “property not found” type of exceptions. Defaults are always a good idea, and since a deployable artifact should be completely self contained, bundling properties during a deploy is a naturally good practice. But what if you want to override these properties with an environmentally dependent set of values?

We can use the jboss “conf” directory. Because jboss uses an instance style of configuration, you can stick your properties in the “/jboss-install-dir/server/configured-instance/conf” directory, and access them easily from within your code. In a nutshell you can ask the System.properties object for the URL location of the “conf” directory, then load your properties file into a local Properties object as a resource. If your property file is not in the “conf” directory, you can then choose to load from the bundled properties (deployed with your archive) the regular way.

Lets take a look at some of the properties jboss loads into System.properties – on startup if you have jboss set up to output debugging during boot, you will eventually see a system property dump like this:

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06:34:04,070 INFO [ServerInfo] Java version: 1.6.0_0,Sun Microsystems Inc.
06:34:04,071 INFO [ServerInfo] Java Runtime: OpenJDK Runtime Environment (build 1.6.0_0-b14)
06:34:04,072 INFO [ServerInfo] Java VM: OpenJDK Client VM 14.0-b08,Sun Microsystems Inc.
06:34:04,072 INFO [ServerInfo] OS-System: Linux 2.6.29.4-167.fc11.i686.PAE,i386
06:34:04,074 DEBUG [ServerInfo] Full System Properties Dump
06:34:04,075 DEBUG [ServerInfo] java.vendor: Sun Microsystems Inc.
06:34:04,076 DEBUG [ServerInfo] sun.java.launcher: SUN_STANDARD
06:34:04,076 DEBUG [ServerInfo] sun.management.compiler: HotSpot Client Compiler
06:34:04,076 DEBUG [ServerInfo] os.name: Linux
06:34:04,076 DEBUG [ServerInfo] user.name: jboss
06:34:04,076 DEBUG [ServerInfo] jboss.bind.address: 192.168.1.252
06:34:04,076 DEBUG [ServerInfo] jboss.home.dir: /jboss/jboss-5.1.0.GA
06:34:04,076 DEBUG [ServerInfo] jboss.home.url: file:/jboss/jboss-5.1.0.GA/
06:34:04,076 DEBUG [ServerInfo] java.version: 1.6.0_0
06:34:04,076 DEBUG [ServerInfo] jboss.server.home.dir: /jboss/jboss-5.1.0.GA/server/standard
06:34:04,077 DEBUG [ServerInfo] jboss.server.home.url: file:/jboss/jboss-5.1.0.GA/server/standard/
06:34:04,077 DEBUG [ServerInfo] jboss.server.config.url: file:/jboss/jboss-5.1.0.GA/server/standard/conf/
06:34:04,077 DEBUG [ServerInfo] jboss.common.lib.url: file:/jboss/jboss-5.1.0.GA/common/lib/
06:34:04,078 DEBUG [ServerInfo] java.home: /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0/jre
06:34:04,078 DEBUG [ServerInfo] java.endorsed.dirs: /jboss/jboss-5.1.0.GA/lib/endorsed*
06:34:04,079 DEBUG [ServerInfo] jboss.lib.url: file:/jboss/jboss-5.1.0.GA/lib/
06:34:04,079 DEBUG [ServerInfo] bind.address: 192.168.1.252
06:34:04,080 DEBUG [ServerInfo] jboss.server.temp.dir: /jboss/jboss-5.1.0.GA/server/standard/tmp
06:34:04,080 DEBUG [ServerInfo] user.home: /home/jboss
06:34:04,080 DEBUG [ServerInfo] jboss.common.base.url: file:/jboss/jboss-5.1.0.GA/common/
06:34:04,080 DEBUG [ServerInfo] jboss.server.log.dir: /jboss/jboss-5.1.0.GA/server/standard/log
06:34:04,081 DEBUG [ServerInfo] java.io.tmpdir: /tmp
06:34:04,081 DEBUG [ServerInfo] jboss.server.data.dir: /jboss/jboss-5.1.0.GA/server/standard/data
06:34:04,081 DEBUG [ServerInfo] java.rmi.server.hostname: 192.168.1.252
06:34:04,082 DEBUG [ServerInfo] user.dir: /jboss/jboss-5.1.0.GA/bin
06:34:04,082 DEBUG [ServerInfo] java.vm.name: OpenJDK Client VM
06:34:04,082 DEBUG [ServerInfo] jboss.server.base.dir: /jboss/jboss-5.1.0.GA/server
06:34:04,082 DEBUG [ServerInfo] jboss.server.base.url: file:/jboss/jboss-5.1.0.GA/server/
06:34:04,082 DEBUG [ServerInfo] file.encoding: UTF-8
06:34:04,082 DEBUG [ServerInfo] jboss.server.name: standard
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Note the bolded entries. You can access these properties by saying something like this:

String serverConfUrl = System.getProperty("jboss.server.config.url")

A more complete solution that would check the server conf directory before loading the bundled properties could look something like this:

String propertiesFileName = "application.properties";

Properties props = new Properties();
String path = System.getProperty("jboss.server.config.url")+propertiesFileName;

if(new File(path).exists()) {
	props.load(new URL(path).openStream());
	log.info("loaded application properties from file: " + path);
} else {
	props.load(MyClass.class.getResourceAsStream("/" + propertiesFileName));
	log.info("loaded application properties: /"+propertiesFileName);
}

There you have it. An easy to use environment specific properties definition strategy with bundled fail over defaults. Try saying that three times.

Related posts:

1. Using Jboss Datasource files
2. External Jboss deploy directories
3. XML, Xalan, Endorsed dirs and &..