java-web-app - sonarqube

Description Jenkins - SonarQube Integration: Build App. Generate Report.

Prerequisities & Tools

• Maven/Java App with Unit Tests
• AWS EC2 Instance - in this case CentOS 8 instance that serves as a host machine for SQ, Jenkins, Docker..
• Jenkins - CI
• SonarQube - Static code analysis
• JaCoCo Plugin - Java code coverage library
• Docker - Run Jenkins and SQ in Docker containers

How to integrate SQ with Jenkins?

Steps

1. Install SonarQube Scanner Plugin
2. Generate Token in SonarQube Server

• Create user jenkins Administration/Security/Users
• Generate Token for jenkins user - this token will be used as a Jenkins credential

3. Configure SQ in Jenkins

• Manage Jenkins/Configure System -> SonarQube Servers/Add Server URL -> Add Jenkins credential (Server auth token_

4. Configure SonarQube Scanner

• Manage Jenkins/Global configuration Tools -> SonarQube Scanner/Install from Maven central

Project Build with Maven

Configuring Plug-ins & Dependencies

• Using JaCoCo Plugin for code coverage analysis in Java, allows basic report creation.

<plugin>
    <groupId>org.jacoco</groupId>
    <artifactId>jacoco-maven-plugin</artifactId>
    <version>0.8.7</version>
    <executions>
       <execution>
          <id>jacoco-init</id>
           <goals>
                <goal>prepare-agent</goal>
           </goals>
       </execution>
       <execution>
          <id>report</id>
          <phase>test</phase>
          <goals>
              <goal>report</goal>
          </goals>
       </execution>
    </executions>
</plugin>

In this case, The JaCoCo Maven plug-in defines the following goals:

1. prepare-agent - initialization phase, to add JaCoCo agent during build
2. report - generate code coverage report

Issues & How to fix?

1. Report not generated due to maven surefire plugin & jacoco conflict.

Explained: The prepare-agent goal will add the jacoco agent during build, but will not cause the actual report to be generated after the tests. As a result, the coverage will always be reported as zero.

Reference:

• https://www.eclemma.org/jacoco/trunk/doc/prepare-agent-mojo.html
• https://maven.apache.org/surefire/maven-surefire-plugin/faq.html#late-property-evaluation

Solution: pom.xml

<properties>
   <surefireArgLine> </surefireArgLine>
</properties>

...

<plugin>
   <artifactId>maven-surefire-plugin</artifactId>
   <version>3.0.0-M5</version>
   <configuration>
       <argLine>${surefireArgLine}</argLine>
   </configuration>
</plugin>

2. Error "Skipping JaCoCo execution due to missing classes directory" while generating report

Explained Not generating classes directory in target directory during build. The only class in the project is the unit test class. test-classes directory is generated. Nothing to compile.

Solution Copy resources. Bad approach?? Probably

<plugin>
   <artifactId>maven-resources-plugin</artifactId>
   <version>3.2.0</version>
   <executions>
       <execution>
           <id>copy-resources</id>
           <phase>pre-integration-test</phase>
           <goals>
               <goal>copy-resources</goal>
           </goals>
           <configuration>
               <outputDirectory>${basedir}/target/classes</outputDirectory>
               <resources>
                   <resource>
                        <directory>${basedir}/target/test-classes</directory>
                       <filtering>false</filtering>
                   </resource>
               </resources>
           </configuration>
       </execution>
   </executions>
</plugin>