Maven Release Plugin use in Jenkins Pipeline

Thanks to @Daniel Omoto comment, I found out that Jenkins provides option for GIT polling. One is exactly what I needed (and the provided example is for maven-release-plugin!):

This is is what we put as a first stage in our pipeline:

stage('Check commit message') {
     when { changelog '.*\\[maven-release-plugin\\].*' }
     steps {
       script {
          pom = readMavenPom file: 'pom.xml'
          currentBuild.displayName = pom.version
          currentBuild.result = 'NOT_BUILT'
       }
       error('Skipping release build')
     }
}

You will need to install https://jenkins.io/doc/pipeline/steps/pipeline-utility-steps/ plugin to read maven pom, or just put a fixed description for the skipped build. The build following the release will have grey colour.

IMHO with the advent of git and pull requests, I don't think using maven-release-plugin or maven-version-plugin with a Jenkins pipeline is a good idea.

Using Multibranch Pipeline with the versioning technique mentioned here is more in line with continuous delivery: https://axelfontaine.com/blog/dead-burried.html

Using the versioning technique above, the pom.xml now looks like this:

<project>
    ...
    <version>${revision}</version>

    <properties>
        <!-- Sane default when no revision property is passed in from the commandline -->
        <revision>0-SNAPSHOT</revision>
    </properties>

    <scm>
        <connection>scm:git:your-git-repo-url</connection>
    </scm>

    <distributionManagement>
        <repository>
            <id>artifact-repository</id>
            <url>your-artifact-repo-url</url>
        </repository>
    </distributionManagement>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-scm-plugin</artifactId>
                <version>1.9.5</version>
                <configuration>
                   <tag>${project.artifactId}-${project.version}</tag>
                </configuration>
            </plugin>
        </plugins>
    </build>
    ...
</project>

You can now produce releases on your Jenkins server very easily by configuring a Multibranch Pipeline with a Jenkinsfile to build on all branches and deploy only from master branch:

pipeline {
  agent any
  environment {
    REVISION = "0.0.${env.BUILD_ID}"
  }
  triggers {
    pollSCM('')
  }
  options {
    disableConcurrentBuilds()
    buildDiscarder(logRotator(numToKeepStr: '30'))
  }
  tools {
    maven '3.5.2'
    jdk 'jdk8'
  }
  stages {
    stage ('Initialize') {
      steps {
        sh '''
          echo "PATH = ${PATH}"
          echo "M2_HOME = ${M2_HOME}"
        '''
      }
    }
    stage ('Build') {
      steps {
        sh 'mvn clean package'
      }
    }
    stage ('Deploy') {
      when {
        branch 'master'
      }
      steps {
        script {
          currentBuild.displayName = "${REVISION}"
        }
        sh 'mvn deploy scm:tag -Drevision=${REVISION}'
      }
    }
  }
} 

See https://jenkins.io/blog/2017/02/07/declarative-maven-project/#set-up on how to configure a Multibranch Pipeline.

With this technique you develop only on non-master branches. Then create a pull request to merge your changes back to master branch. This should then deploy your artifact automatically to your artifact repository.

---

Addendum

When publishing to a Maven repository using the above method, the pom.xml will not have the proper version. To get Maven to publish the proper version, use the flatten-maven-plugin: http://www.mojohaus.org/flatten-maven-plugin/usage.html.

Also, check out: https://maven.apache.org/maven-ci-friendly.html

In case somebody has the same problem with the loop or that subsequent builds get triggered BUT has a Trigger who starts the jenkins pipeline on every push to the repository (Instead of polling).

Here is who I did it: I checked if the last commit contains "[maven-release-plugin]" in the comment.

Code in jenkinsfile:

def lastCommit = sh returnStdout: true, script: 'git log -1 --pretty=%B'

if (lastCommit.contains("[maven-release-plugin]")){
            sh "echo  Maven release detected"  //dont trigger build

        } else {
            sh "echo Last commit is not from maven release plugin" //do build steps 
            <..build Job...>
        }