How to make use of variables in Wildfly configuration file?

Question

I am setting up a common standalone-full.xml file for all server environments, and therefore need to have variables for database URL's (and such), instead of hard coding them.

One such section in the configuration file might look like this:

<datasource jta="true" jndi-name="java:/somename" pool-name="somename" enabled="true" use-ccm="false">
                <connection-url>jdbc:mysql://${SOMENAME_DB_URL}</connection-url>
                <driver-class>com.mysql.jdbc.Driver</driver-class>
                <driver>mysql</driver>
                <pool>
                    <min-pool-size>5</min-pool-size>
                    <max-pool-size>15</max-pool-size>
                </pool>
                <security>
                    <user-name>${DB_USERNAME}</user-name>
                    <password>${DB_PASSWORD}</password>
                </security>
                <validation>
                    <validate-on-match>false</validate-on-match>
                    <background-validation>false</background-validation>
                </validation>
                <statement>
                    <share-prepared-statements>false</share-prepared-statements>
                </statement>
            </datasource>

However, upon starting the server with this config file it simply throws an "Unable to resolve expression" error for all such sections.

I've tried putting the variables in /etc/environment, as well as in the .jbossclirc file in /bin using set DB_USERNAME=mydbusername, but to no avail.

As you can see I'm fumbling a bit in the dark here since I haven't been able to find any proper documentation on how to do this. I'm not even sure if it's actually possible. Any help is greatly appreciated.

Answer 1

You should use Java system properties instead of environment variables.

You can also pass these properties as -D arguments to standalone.sh, e.g.

bin/standalone.sh -DDB_USERNAME=me -DDB_PASSWORD=secret

Alternatively, you can define your properties in a properties file and pass that to the startup script with a -P option:

bin/standalone.sh -P database.properties