Jenkins Pipeline as Code. Code for blog post http://fishi.devtail.io/weblog/E/

docker-build.groovy

node {
  def branchVersion = ""

  stage ('Checkout') {
    // checkout repository
    checkout scm

    // save our docker build context before we switch branches
    sh "cp -r ./.docker/build tmp-docker-build-context"
    
    // checkout input branch 
    sh "git checkout ${caller.env.BRANCH_NAME}"
  }

  stage ('Determine Branch Version') {
    // add maven to path
    env.PATH = "${tool 'M3'}/bin:${env.PATH}"

    // determine version in pom.xml
    def pomVersion = sh(script: 'mvn -q -Dexec.executable=\'echo\' -Dexec.args=\'${project.version}\' --non-recursive exec:exec', returnStdout: true).trim()

    // compute proper branch SNAPSHOT version
    pomVersion = pomVersion.replaceAll(/-SNAPSHOT/, "") 
    branchVersion = env.BRANCH_NAME
    branchVersion = branchVersion.replaceAll(/origin\//, "") 
    branchVersion = branchVersion.replaceAll(/\W/, "-")
    branchVersion = "${pomVersion}-${branchVersion}-SNAPSHOT"

    // set branch SNAPSHOT version in pom.xml
    sh "mvn versions:set -DnewVersion=${branchVersion}"
  }

  stage ('Java Build') {
    // build .war package
    sh 'mvn clean package -U'
  }
  
  stage ('Docker Build') {
    // prepare docker build context
    sh "cp target/project.war ./tmp-docker-build-context"

    // Build and push image with Jenkins' docker-plugin
    withDockerServer([uri: "tcp://<my-docker-socket>"]) {
      withDockerRegistry([credentialsId: 'docker-registry-credentials', url: "https://<my-docker-registry>/"]) {
        // we give the image the same version as the .war package
        def image = docker.build("<myDockerRegistry>/<myDockerProjectRepo>:${branchVersion}", "--build-arg PACKAGE_VERSION=${branchVersion} ./tmp-docker-build-context")
        image.push()
      }   
    }
  }
}

docker-entrypoint.sh

#!/bin/sh
set -e

if [ -n "$SERVER_XML" ]
then
  echo ${SERVER_XML} > /usr/local/tomcat/conf/server.xml
fi

if [ -n "$CONTEXT_XML" ]
then
  echo ${CONTEXT_XML} > /usr/local/tomcat/conf/context.xml
fi

exec "$@"

Dockerfile

FROM tomcat:8.0.38

# Place the code version inside the webapps directory
ARG PACKAGE_VERSION
RUN echo "${PACKAGE_VERSION}" >> /usr/local/tomcat/webapps/version.txt

COPY project.war /usr/local/tomcat/webapps/project.war
COPY docker-entrypoint.sh /
RUN chmod +x /docker-entrypoint.sh
ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["catalina.sh", "run"]

#####
# IMPORTANT: By default, this container will run as root user, which is not recommended for security reasons!!!
#####

initial-test-build.groovy

node {
  echo 'The pipeline started'
}

java-build.groovy

node {
  def branchVersion = ""

  stage ('Checkout') {
    // checkout repository
    checkout scm

    // checkout input branch 
    sh "git checkout ${caller.env.BRANCH_NAME}"
  }

  stage ('Determine Branch Version') {
    // add maven to path
    env.PATH = "${tool 'M3'}/bin:${env.PATH}"

    // determine version in pom.xml
    def pomVersion = sh(script: 'mvn -q -Dexec.executable=\'echo\' -Dexec.args=\'${project.version}\' --non-recursive exec:exec', returnStdout: true).trim()

    // compute proper branch SNAPSHOT version
    pomVersion = pomVersion.replaceAll(/-SNAPSHOT/, "") 
    branchVersion = env.BRANCH_NAME
    branchVersion = branchVersion.replaceAll(/origin\//, "") 
    branchVersion = branchVersion.replaceAll(/\W/, "-")
    branchVersion = "${pomVersion}-${branchVersion}-SNAPSHOT"

    // set branch SNAPSHOT version in pom.xml
    sh "mvn versions:set -DnewVersion=${branchVersion}"
  }

  stage ('Java Build') {
    // build .war package
    sh 'mvn clean package -U'
  }
}

slack-build.groovy

def greenColor = "#3BCF00"
def yellowColor = "#BFC14C"
def redColor = "#DE0000"

def buildNotify(buildStatus, channel) {
    // build status of null means successful
    buildStatus =  buildStatus ?: 'SUCCESSFUL'

    // Default values
    def colorCode = '#FF0000'
    def subject = "`[PROJECT]` ${buildStatus}: build branch `${env.BRANCH_NAME}`"
    def summary = "${subject} (<${env.BUILD_URL}|Open>)"

    // Override default values based on build status
    if (buildStatus == 'STARTED') {
      colorCode = yellowColor
    } else if (buildStatus == 'SUCCESSFUL') {
      colorCode = greenColor
    } else {
      colorCode = redColor
    }   

    // Send notifications
    // NOTE: you should get the token from Jenkins credentials instead of cleartext in script
    slackSend color: colorCode, message: summary, teamDomain: 'myDomain', channel: channel,token: 'myToken'
  }

node {
  def branchVersion = ""

  try {
    buildNotify 'STARTED', 'my-build-channel'
    
    stage ('Checkout') {
      // checkout repository
      checkout scm

      // save our docker build context before we switch branches
      sh "cp -r ./.docker/build tmp-docker-build-context"
    
      // checkout input branch 
      sh "git checkout ${caller.env.BRANCH_NAME}"
    }

    stage ('Determine Branch Version') {
      // add maven to path
      env.PATH = "${tool 'M3'}/bin:${env.PATH}"

      // determine version in pom.xml
      def pomVersion = sh(script: 'mvn -q -Dexec.executable=\'echo\' -Dexec.args=\'${project.version}\' --non-recursive exec:exec', returnStdout: true).trim()

      // compute proper branch SNAPSHOT version
      pomVersion = pomVersion.replaceAll(/-SNAPSHOT/, "") 
      branchVersion = env.BRANCH_NAME
      branchVersion = branchVersion.replaceAll(/origin\//, "") 
      branchVersion = branchVersion.replaceAll(/\W/, "-")
      branchVersion = "${pomVersion}-${branchVersion}-SNAPSHOT"

      // set branch SNAPSHOT version in pom.xml
      sh "mvn versions:set -DnewVersion=${branchVersion}"
    }

    stage ('Java Build') {
      // build .war package
      sh 'mvn clean package -U'
    }
  
    stage ('Docker Build') {
      // prepare docker build context
      sh "cp target/project.war ./tmp-docker-build-context"

      // Build and push image with Jenkins' docker-plugin
      withDockerServer([uri: "tcp://<my-docker-socket>"]) {
        withDockerRegistry([credentialsId: 'docker-registry-credentials', url: "https://<my-docker-registry>/"]) {
          // we give the image the same version as the .war package
          def image = docker.build("<myDockerRegistry>/<myDockerProjectRepo>:${branchVersion}", "--build-arg PACKAGE_VERSION=${branchVersion} ./tmp-docker-build-context")
          image.push()
        }   
      }
    } 
  } catch(e) {
    currentBuild.result = "FAILED"
    throw e
  } finally {
    buildNotify currentBuild.result, 'my-build-channel'
  }
}