221
votes

Are comments possible in a Jenkinsfile? If so, what's the syntax?

I am using the declarative pipeline syntax.

I want to comment out the "post" section below until my SMTP server is working.

pipeline {

  agent { label 'docker-build-slave' }

  environment {
    IMAGE = 'registry.gitlab.com/XXXXX/bible-server'
    DOCKER_REGISTRY_CREDENTIALS = credentials('DOCKER_REGISTRY_CREDENTIALS')
  }

  options {
    timeout(10)
  }

  stages {

    stage('Test') {
      steps {
        sh 'yarn'
        sh 'npm test'
      }
    }

    stage('Build') {
      when {
        branch '*/master'
      }
      steps {
        sh 'docker login -u ${DOCKER_REGISTRY_CREDENTIALS_USR} -p ${DOCKER_REGISTRY_CREDENTIALS_PSW} registry.gitlab.com'
        sh 'docker build -t ${IMAGE}:${BRANCH_NAME} .'
        sh 'docker push ${IMAGE}:${BRANCH_NAME}'
      }
    }

    stage('Deploy') {
      when {
        branch '*/master'
      }
      steps {
        echo 'Deploying ..'
      }
    }
  }

  post {
    success {
      mail to: "[email protected]", subject:"SUCCESS: ${currentBuild.fullDisplayName}", body: "Yay, we passed."
    }
    failure {
      mail to: "[email protected]", subject:"FAILURE: ${currentBuild.fullDisplayName}", body: "Boo, we failed."
    }
  }
}
4
Whenever you have such language questions about Jenkinsfiles, just remember they are mostly GROOVY scripts. So it is possible you will find more results if you add the keyword "groovy" rather than "Jenkinsfile".Raúl Salinas-Monteagudo

4 Answers

358
votes

The Jenkinsfile is written in groovy which uses the Java (and C) form of comments:

/* this
   is a
   multi-line comment */

// this is a single line comment
26
votes

You can use block (/***/) or single line comment (//) for each line. You should use "#" in sh command.

Block comment

/*  
post {
    success {
      mail to: "[email protected]", 
      subject:"SUCCESS: ${currentBuild.fullDisplayName}", 
      body: "Yay, we passed."
    }
    failure {
      mail to: "[email protected]", 
      subject:"FAILURE: ${currentBuild.fullDisplayName}", 
      body: "Boo, we failed."
    }
  }
*/

Single Line

// post {
//     success {
//       mail to: "[email protected]", 
//       subject:"SUCCESS: ${currentBuild.fullDisplayName}", 
//       body: "Yay, we passed."
//     }
//     failure {
//       mail to: "[email protected]", 
//       subject:"FAILURE: ${currentBuild.fullDisplayName}", 
//       body: "Boo, we failed."
//     }
// }

Comment in 'sh' command

        stage('Unit Test') {
            steps {
                ansiColor('xterm'){
                  sh '''
                  npm test
                  # this is a comment in sh
                  '''
                }
            }
        }
3
votes

The official Jenkins documentation only mentions single line commands like the following:

// Declarative //

and (see)

pipeline {
    /* insert Declarative Pipeline here */
}

The syntax of the Jenkinsfile is based on Groovy so it is also possible to use groovy syntax for comments. Quote:

/* a standalone multiline comment
   spanning two lines */
println "hello" /* a multiline comment starting
                   at the end of a statement */
println 1 /* one */ + 2 /* two */

or

/**
 * such a nice comment
 */
1
votes

Comments work fine in any of the usual Java/Groovy forms, but you can't currently use groovydoc to process your Jenkinsfile (s).

First, groovydoc chokes on files without extensions with the wonderful error

java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.codehaus.groovy.tools.GroovyStarter.rootLoader(GroovyStarter.java:109)
    at org.codehaus.groovy.tools.GroovyStarter.main(GroovyStarter.java:131)
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -1
    at java.lang.String.substring(String.java:1967)
    at org.codehaus.groovy.tools.groovydoc.SimpleGroovyClassDocAssembler.<init>(SimpleGroovyClassDocAssembler.java:67)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.parseGroovy(GroovyRootDocBuilder.java:131)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.getClassDocsFromSingleSource(GroovyRootDocBuilder.java:83)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.processFile(GroovyRootDocBuilder.java:213)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.buildTree(GroovyRootDocBuilder.java:168)
    at org.codehaus.groovy.tools.groovydoc.GroovyDocTool.add(GroovyDocTool.java:82)
    at org.codehaus.groovy.tools.groovydoc.GroovyDocTool$add.call(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
    at org.codehaus.groovy.tools.groovydoc.Main.execute(Main.groovy:214)
    at org.codehaus.groovy.tools.groovydoc.Main.main(Main.groovy:180)
    ... 6 more

... and second, as far as I can tell Javadoc-style commments at the start of a groovy script are ignored. So even if you copy/rename your Jenkinsfile to Jenkinsfile.groovy, you won't get much useful output.

I want to be able to use a

/**
 * Document my Jenkinsfile's overall purpose here
 */

comment at the start of my Jenkinsfile. No such luck (yet).

groovydoc will process classes and methods defined in your Jenkinsfile if you pass -private to the command, though.