Environment Specific Filtering

Most of the time resource files for different environments are largely the same. They only have minor differences. In those scenarios it is quite cumborsome to parse through the entire file to find the small changes. It makes sense to put those minor differences in a properties files and move the full files to a common location. For example take logback.xml file. The file is usually only differs in server address, port and a few other things. It makes sense to move those into a properties file in each of the environment directories and move a single logback.xml file into a common location. So the directory structure looks something like this.

• src/
  • main/
    • environments/
      • common/
        • logback.xml
      • dev/
        • envspec.properties
      • ci/
        • envspec.properties
      • qa/
        • envspec.properties

Now all wars will have logback.xml and the logback.xml is filtered using envspec.properties for each environment individually.

With this there will be two steps to filtering:

1. All files in src/main/environments are filtered using the files listed in the filter tags in build section. This includes the common directory.
2. Then environments-maven filters the common files using the key/value pairs from the properties file declared in filters tag inside the configuration segment of environments maven plugin. For this filtering to work user should declare both commonDir and filters attributes.

	<plugin>
		<groupId>net.sf.environments-maven-plugin</groupId>
		<artifactId>environments-maven-plugin</artifactId>
		<version>1.1.0-SNAPSHOT</version>
		<configuration>
			<targetPath>some/where/inside</targetPath>
			<commonDir>common</commonDir>
			<filters>
				<filter>envspec.properties</filter>
			</filters>
		</configuration>
		<executions>
			<execution>
				<goals>
					<goal>environment</goal>
				</goals>
			</execution>
		</executions>
	</plugin>

NOTE:

• If only commonDir is declared then all the files in commonDir will be included in the archives.
  • If only filters are declared and no commonDir is declared then this will have no impact on the archives.
  • If you have no intention of using a common directory you should declare filters in the build section of the pom.