environment-variables.md

title	Environment Variables
icon	creative

Environment Variables

Environment variables offer a way to make configuration data available at the start of a process. They are the same for all process instances. They can be defined by adding a member variable with the Spring-Framework @Value annotation to a configuration class (a class annotated with the Spring-Framework @Configuration annotation). The value of the annotation uses the ${..} notation and follows the form ${some.property:defaultValue}, where each dot in the property name corresponds to an underscore in the equivalent environment variable. Environment variables are always written upper-case. The property some.property therefore corresponds to the environment variable SOME_PROPERTY.

@Configuration
public class MyConfiguration
{
	@Value("${my.org.my.value}")
	private String myValue;
}

The DSF provides a feature to automatically generate documentation of environment variables during the Maven build process. The @ProcessDocumentation annotation causes the build process to automatically generate Markdown documentation for all fields with this annotation.

@Configuration
public class MyConfiguration
{
	@ProcessDocumentation(processNames = "myorg_MyProcess", description = "My process description", required = true, recommendation = "Foo")
	@Value("${my.org.my.value}")
	private String myValue;
}

This requires the DSF Maven Plugin to be configured in the pom.xml file of the project. A configuration to generate documentation for a package my.org.spring.config containing all Spring configuration classes looks like this:

<plugin>
    <groupId>dev.dsf</groupId>
    <artifactId>dsf-maven-plugin</artifactId>
    <version>2.0.2</version>
    <executions>
        <execution>
            <goals>
                <goal>generate-config-doc</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <configDocPackages>dev.dsf.bpe.config</configDocPackages>
    </configuration>
</plugin>

Maven build plugins will be executed during the build phase and should be configured in the <build/> element from the pom.xml.

Related Topics

Spring Framework Integration