Chapter 36. The SonarQube Runner Plugin

The default version of the SonarQube Runner used by the plugin is 2.3, which makes it compatible with SonarQube 3.0 and higher. For compatibility with SonarQube versions earlier than 3.0, you can configure the use of an earlier SonarQube Runner version (see Section 36.4, “Specifying the SonarQube Runner version”).

To get started, apply the SonarQube Runner plugin to the project to be analyzed.

apply plugin: "sonar-runner"

Assuming a local SonarQube server with out-of-the-box settings is up and running, no further mandatory configuration is required. Execute gradle sonarRunner and wait until the build has completed, then open the web page indicated at the bottom of the SonarQube Runner output. You should now be able to browse the analysis results.

Before executing the sonarRunner task, all tasks producing output to be analysed by SonarQube need to be executed. Typically, these are compile tasks, test tasks, and code coverage tasks. To meet these needs, the plugins adds a task dependency from sonarRunner on test if the java plugin is applied. Further task dependencies can be added as needed.

The SonarQube Runner plugin adds a SonarRunnerRootExtension extension to the project and a SonarRunnerExtension extension to its subprojects, which allows you to configure the SonarQube Runner via key/value pairs known as SonarQube properties. A typical base line configuration includes connection settings for the SonarQube server and database.

sonarRunner {
    sonarProperties {
        property "sonar.host.url", "http://my.server.com"
        property "sonar.jdbc.url", "jdbc:mysql://my.server.com/sonar"
        property "sonar.jdbc.driverClassName", "com.mysql.jdbc.Driver"
        property "sonar.jdbc.username", "Fred Flintstone"
        property "sonar.jdbc.password", "very clever"
    }
}

Alternatively, SonarQube properties can be set from the command line. See Section 35.6, “Configuring Sonar Settings from the Command Line” for more information.

For a complete list of standard SonarQube properties, consult the SonarQube documentation. If you happen to use additional SonarQube plugins, consult their documentation.

In addition to set SonarQube properties, the SonarRunnerRootExtension extension allows the configuration of the SonarQube Runner version and the JavaForkOptions of the forked SonarQube Runner process.

The SonarQube Runner plugin leverages information contained in Gradle's object model to provide smart defaults for many of the standard SonarQube properties. The defaults are summarized in the tables below. Notice that additional defaults are provided for projects that have the java-base or java plugin applied. For some properties (notably server and database connection settings), determining a suitable default is left to the SonarQube Runner.

By default, version 2.3 of the SonarQube Runner is used. To specify an alternative version, set the SonarRunnerRootExtension.getToolVersion() property of the sonarRunner extension of the project the plugin was applied to to the desired version. This will result in the SonarQube Runner dependency org.codehaus.sonar.runner:sonar-runner-dist:«toolVersion» being used as the SonarQube Runner.

sonarRunner {
    toolVersion = '2.3' // default
}

The SonarQube Runner is capable of analyzing whole project hierarchies at once. This yields a hierarchical view in the SonarQube web interface, with aggregated metrics and the ability to drill down into subprojects. Analyzing a project hierarchy also takes less time than analyzing each project separately.

To analyze a project hierarchy, apply the SonarQube Runner plugin to the root project of the hierarchy. Typically (but not necessarily) this will be the root project of the Gradle build. Information pertaining to the analysis as a whole, like server and database connections settings, have to be configured in the sonarRunner block of this project. Any SonarQube properties set on the command line also apply to this project.

sonarRunner {
    sonarProperties {
        property "sonar.host.url", "http://my.server.com"
        property "sonar.jdbc.url", "jdbc:mysql://my.server.com/sonar"
        property "sonar.jdbc.driverClassName", "com.mysql.jdbc.Driver"
        property "sonar.jdbc.username", "Fred Flintstone"
        property "sonar.jdbc.password", "very clever"
    }
}

Configuration shared between subprojects can be configured in a subprojects block.

subprojects {
    sonarRunner {
        sonarProperties {
            property "sonar.sourceEncoding", "UTF-8"
        }
    }
}

Project-specific information is configured in the sonarRunner block of the corresponding project.

project(":project1") {
    sonarRunner {
        sonarProperties {
            property "sonar.language", "grvy"
        }
    }
}

To skip SonarQube analysis for a particular subproject, set sonarRunner.skipProject to true.

project(":project2") {
    sonarRunner {
        skipProject = true
    }
}

By default, the SonarQube Runner plugin passes on the project's main source set as production sources, and the project's test source set as test sources. This works regardless of the project's source directory layout. Additional source sets can be added as needed.

sonarRunner {
    sonarProperties {
        properties["sonar.sources"] += sourceSets.custom.allSource.srcDirs
        properties["sonar.tests"] += sourceSets.integTest.allSource.srcDirs
    }
}

As of SonarQube 4.2, multi-language projects are supported and each file language will be detected according to its filename suffix. However, note that your SonarQube server has to have the SonarQube plugin that handles that programming language. If you want to enforce a single language for your project, you'll need to set sonar.project.language accordingly.

sonarRunner {
    sonarProperties {
        property "sonar.language", "grvy" // set language to Groovy
    }
}

Let's take a closer look at the sonarRunner.sonarProperties {} block. As we have already seen in the examples, the property() method allows you to set new properties or override existing ones. Furthermore, all properties that have been configured up to this point, including all properties preconfigured by Gradle, are available via the properties accessor.

Entries in the properties map can be read and written with the usual Groovy syntax. To facilitate their manipulation, values still have their “idiomatic” type (File, List, etc.). After the sonarProperties block has been evaluated, values are converted to Strings as follows: Collection values are (recursively) converted to comma-separated Strings, and all other values are converted by calling their toString() method.

Because the sonarProperties block is evaluated lazily, properties of Gradle's object model can be safely referenced from within the block, without having to fear that they have not yet been set.

SonarQube Properties can also be set from the command line, by setting a system property named exactly like the Sonar property in question. This can be useful when dealing with sensitive information (e.g. credentials), environment information, or for ad-hoc configuration.

gradle sonarRunner -Dsonar.host.url=http://sonar.mycompany.com -Dsonar.jdbc.password=myPassword -Dsonar.verbose=true

A SonarQube property value set via a system property overrides any value set in a build script (for the same property). When analyzing a project hierarchy, values set via system properties apply to the root project of the analyzed hierarchy. Each system property starting with ""sonar." will taken into account for the sonar runner setup.

The SonarQube Runner is executed in a forked process. This allows fine grained control over memory settings, system properties etc. just for the SonarQube Runner process. The forkOptions property of the sonarRunner extension of the project that applies the sonar-runner plugin (Usually the rootProject but not necessarily) allows the process configuration to be specified. This property is not available in the SonarRunnerExtension extension applied to the subprojects.

sonarRunner {
    forkOptions {
        maxHeapSize = '512m'
    }
}

For a complete reference about the available options, see JavaForkOptions.

The SonarQube Runner plugin adds the following tasks to the project.