Chapter 62. The Sonar Plugin

Table of Contents

62.1. Usage
62.2. Analyzing Multi-Project Builds
62.3. Analyzing Custom Source Sets
62.4. Analyzing languages other than Java
62.5. Setting Custom Sonar Properties
62.6. Configuring Sonar Settings from the Command Line
62.7. Tasks

This plugin has been deprecated and superseded by the official plugin from SonarQube. This plugin will be removed in Gradle 3.0.

The Sonar plugin provides integration with Sonar, a web-based platform for monitoring code quality. The plugin adds a sonarAnalyze task that analyzes the project to which the plugin is applied, as well as its subprojects. The results are stored in the Sonar database. The plugin is based on the Sonar Runner and requires Sonar 2.11 or higher.

The sonarAnalyze task is a standalone task that needs to be executed explicitly and doesn't depend on any other tasks. Apart from source code, the task also analyzes class files and test result files (if available). For best results, it is therefore recommended to run a full build before the analysis. In a typical setup, analysis would be performed once per day on a build server.

62.1. Usage

At a minimum, the Sonar plugin has to be applied to the project.

Example 62.1. Applying the Sonar plugin

build.gradle

apply plugin: "sonar"

Unless Sonar is run locally and with default settings, it is necessary to configure connection settings for the Sonar server and database.

Example 62.2. Configuring Sonar connection settings

build.gradle

sonar {
    server {
        url = "http://my.server.com"
    }
    database {
        url = "jdbc:mysql://my.server.com/sonar"
        driverClassName = "com.mysql.jdbc.Driver"
        username = "Fred Flintstone"
        password = "very clever"
    }
}

Alternatively, some or all connection settings can be set from the command line (see Section 62.6, “Configuring Sonar Settings from the Command Line”).

Project settings determine how the project is going to be analyzed. The default configuration works well for analyzing standard Java projects and can be customized in many ways.

Example 62.3. Configuring Sonar project settings

build.gradle

sonar {
    project {
        coberturaReportPath = file("$buildDir/cobertura.xml")
    }
}

The sonar, server, database, and project blocks in the examples above configure objects of type SonarRootModel, SonarServer, SonarDatabase, and SonarProject, respectively. See their API documentation for further information.

62.2. Analyzing Multi-Project Builds

The Sonar plugin is capable of analyzing a whole project hierarchy at once. This yields a hierarchical view in the Sonar web interface with aggregated metrics and the ability to drill down into subprojects. It is also faster than analyzing each project separately.

To analyze a project hierarchy, the Sonar plugin needs to be applied to the top-most project of the hierarchy. Typically (but not necessarily) this will be the root project. The sonar block in that project configures an object of type SonarRootModel. It holds all global configuration, most importantly server and database connection settings.

Example 62.4. Global configuration in a multi-project build

build.gradle

apply plugin: "sonar"

sonar {
    server {
        url = "http://my.server.com"
    }
    database {
        url = "jdbc:mysql://my.server.com/sonar"
        driverClassName = "com.mysql.jdbc.Driver"
        username = "Fred Flintstone"
        password = "very clever"
    }
}

Each project in the hierarchy has its own project configuration. Common values can be set from a parent build script.

Example 62.5. Common project configuration in a multi-project build

build.gradle

subprojects {
    sonar {
        project {
            sourceEncoding = "UTF-8"
        }
    }
}

The sonar block in a subproject configures an object of type SonarProjectModel.

Projects can also be configured individually. For example, setting the skip property to true prevents a project (and its subprojects) from being analyzed. Skipped projects will not be displayed in the Sonar web interface.

Example 62.6. Individual project configuration in a multi-project build

build.gradle

project(":project1") {
    sonar {
        project {
            skip = true
        }
    }
}

Another typical per-project configuration is the programming language to be analyzed. Note that Sonar can only analyze one language per project.

Example 62.7. Configuring the language to be analyzed

build.gradle

project(":project2") {
    sonar {
        project {
            language = "groovy"
        }
    }
}

When setting only a single property at a time, the equivalent property syntax is more succinct:

Example 62.8. Using property syntax

build.gradle

project(":project2").sonar.project.language = "groovy"

62.3. Analyzing Custom Source Sets

By default, the Sonar plugin will analyze the production sources in the main source set and the test sources in the test source set. This works independent of the project's source directory layout. Additional source sets can be added as needed.

Example 62.9. Analyzing custom source sets

build.gradle

sonar.project {
    sourceDirs += sourceSets.custom.allSource.srcDirs
    testDirs += sourceSets.integTest.allSource.srcDirs
}

62.4. Analyzing languages other than Java

To analyze code written in a language other than Java, install the corresponding Sonar plugin, and set sonar.project.language accordingly:

Example 62.10. Analyzing languages other than Java

build.gradle

sonar.project {
    language = "grvy" // set language to Groovy
}

As of Sonar 3.4, only one language per project can be analyzed. You can, however, set a different language for each project in a multi-project build.

62.5. Setting Custom Sonar Properties

Eventually, most configuration is passed to the Sonar code analyzer in the form of key-value pairs known as Sonar properties. The SonarProperty annotations in the API documentation show how properties of the plugin's object model get mapped to the corresponding Sonar properties. The Sonar plugin offers hooks to post-process Sonar properties before they get passed to the code analyzer. The same hooks can be used to add additional properties which aren't covered by the plugin's object model.

For global Sonar properties, use the withGlobalProperties hook on SonarRootModel:

Example 62.11. Setting custom global properties

build.gradle

sonar.withGlobalProperties { props ->
    props["some.global.property"] = "some value"
    // non-String values are automatically converted to Strings
    props["other.global.property"] = ["foo", "bar", "baz"]
}

For per-project Sonar properties, use the withProjectProperties hook on SonarProject:

Example 62.12. Setting custom project properties

build.gradle

sonar.project.withProjectProperties { props ->
    props["some.project.property"] = "some value"
    // non-String values are automatically converted to Strings
    props["other.project.property"] = ["foo", "bar", "baz"]
}

A list of available Sonar properties can be found in the Sonar documentation. Note that for most of these properties, the Sonar plugin's object model has an equivalent property, and it isn't necessary to use a withGlobalProperties or withProjectProperties hook. For configuring a third-party Sonar plugin, consult the plugin's documentation.

62.6. Configuring Sonar Settings from the Command Line

The following properties can alternatively be set from the command line, as task parameters of the sonarAnalyze task. A task parameter will override any corresponding value set in the build script.

  • server.url
  • database.url
  • database.driverClassName
  • database.username
  • database.password
  • showSql
  • showSqlResults
  • verbose
  • forceAnalysis

Here is a complete example:

gradle sonarAnalyze --server.url=http://sonar.mycompany.com --database.password=myPassword --verbose

If you need to set other properties from the command line, you can use system properties to do so:

Example 62.13. Implementing custom command line properties

build.gradle

sonar.project {
    language = System.getProperty("sonar.language", "java")
}

However, keep in mind that it is usually best to keep configuration in the build script and under source control.

62.7. Tasks

The Sonar plugin adds the following tasks to the project.

Table 62.1. Sonar plugin - tasks

Task name Depends on Type Description
sonarAnalyze - SonarAnalyze Analyzes a project hierarchy and stores the results in the Sonar database.