Using a declarative or scripted pipeline in DevOps

  • Release version: Washingtondc
  • Updated August 1, 2024
  • 3 minutes to read
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    Summary of Using a Declarative or Scripted Pipeline in DevOps

    Utilizing a Jenkinsfile in DevOps automates the mapping and association of orchestration tasks to steps within your pipeline. This text file, stored in source control, outlines your Jenkins pipeline definition. It is crucial to set the Track field to True to receive job notifications from Jenkins for all active configurations.

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    Key Features

    • Job Notifications: Notifications are sent when the Track field is True.
    • Pipeline Commands: Commands like snDevOpsChange, snDevOpsArtifact, snDevOpsPackage, snDevOpsGetChangeNumber, snDevOpsUpdateChangeInfo, and snDevOpsSecurityResult enable various functionalities such as error handling and artifact registration.
    • Configuration Management: Specify Jenkins server configurations using the configurationName attribute; a default configuration applies if none is provided.
    • Snippet Generator: The Jenkins Snippet Generator helps create template codes for orchestration tasks, enhancing the efficiency of pipeline creation.

    Key Outcomes

    By implementing these pipelines, ServiceNow customers can effectively manage change requests, configure security scans, and handle artifacts through streamlined automation. The structured approach to nested and parallel stages ensures clarity in orchestration tasks, associating them accurately with parent root-level stages.

    When you use a Jenkinsfile, steps are created, mapped, and associated to orchestration tasks automatically instead of manually.

    Jenkinsfile is a text file that contains the definition of a Jenkins pipeline and is checked into source control.

    Each root-level stage configured in the Jenkinsfile is discovered as a separate orchestration task in DevOps that is mapped to an individual step.

    Note:
    The Track field for the pipeline must be set to True in DevOps to receive job notifications from Jenkins. All active Jenkins configurations will receive job notifications when this field is set to True.

    DevOps Jenkinsfile commands

    • snDevOpsChange(ignoreErrors:{true/false},changeRequestDetails:{setCloseCode:{true/false},attributes:})

      Where ignoreErrors specifies the setting to prevent job failure if there is an error (true/false)

      Where changeRequestDetails specifies closure code and change request fields from within the pipeline

      Enables change control for each root-level stage that is mapped to a DevOps step.

    • snDevOpsArtifact

      Registers artifacts when configuring Artifacts and packages.

    • snDevOpsPackage

      Creates a package for artifacts when configuring Artifacts and packages.

    • snDevOpsGetChangeNumber

      Retrieves the change request number in a Jenkins pipeline based on specific change details.

    • snDevOpsUpdateChangeInfo

      Updates the change request details associated with a Jenkins pipeline.

    • snDevOpsSecurityResult

      Configures security scans on any stage of the pipeline and the scan details are retrieved from the corresponding stage to DevOps Change Velocity.

    You can specify the Jenkins server configuration in any of these steps by passing the configurationName attribute in your pipeline. If the configuration name is not specified in any step, the default configuration will be used in that step. Passing an incorrect configuration name will result in the step to fail unless the Ignore ServiceNow DevOps errors option is selected while configuring the Jenkins plugin.

    Note:
    Stage mapping is only supported for stages at the root level, not nested or parallel stages.

    Jenkins snippet generator for DevOps

    You can use the Jenkins Snippet Generator utility to generate a template code for the orchestration tasks for scripted pipelines. You can use the snippet generator utility to create template for the following orchestration tasks.
    • SnDevOpsArtifact
    • SnDevOpsChange
    • SnDevOpsPackage
    • snDevOpsGetChangeNumber
    • snDevOpsUpdateChangeInfo
    • snDevOpsSecurityResult
    To generate a step snippet, navigate to the Pipeline Syntax from a configured pipeline, select the step from the Sample Step list, and update the values for different variables in the step. Select the ignore error option to prevent job failure if there is an error. Select Generate Pipeline Script to create a snippet. You can copy and paste the snippet into a pipeline.
    Example of a pipeline script for the SnDevOpsChange task:
    snDevOpsChange changeCreationTimeOut: 3600, changeRequestDetails: '{ "attributes": { "short_description": "Test description", "priority": "1", "start_date": "2021-02-05 08:00:00", "end_date": "2022-04-05 08:00:00", "justification": "test justification", "description": "test description", "cab_required": true, "comments": "This update for work notes is from jenkins file", "work_notes": "test work notes", "assignment_group": "a715cd759f2002002920bde8132e7018" }, "setCloseCode": false, "autoCloseChange": true }', changeStepTimeOut: 18000, configurationName: 'Jenkins1', pollingInterval: 60

    Parallel and sub-stage support

    When a stage (or set of parallel stages) is nested within a pipeline stage, these rules apply:

    • Any action from the nested stage is processed as part of the parent root-level stage
    • Only one change request is created (at the parent root level) even if multiple stages nested under the parent root-level stage trigger a change
    • Orchestration tasks created are always associated with the parent root-level stage (not the nested stage)

    Sub stage

    In this sub-stage example, if a change request gets created from the sub stage (deploy PROD), the details of the parent root-level stage (deploy) are used in the change request, and orchestration tasks are also associated with the parent root-level stage (deploy).

    
    stage("deploy") {
             stages{
                 stage('deploy UAT') {
                    when{
                       branch 'dev'
                    }
                stage('deploy PROD') {
                   when {
                      branch 'master'
                   }
                    steps{
                      
                      snDevOpsChange()              
                    }
                }
            }

    Parallel stage

    In this parallel stage example, if a change request is created from a sub stage (UAT test-1 and/or UAT static code test), only the first change request is created (using the details of the parent root-level stage, UAT test) regardless of whether both sub stages (UAT test-1 and UAT static code test) get triggered.

    There is no indication of which parallel stage generated the change, and orchestration tasks are associated with the parent root-level stage (UAT test).

    
    stage('UAT test') {
          parallel {
              stage('UAT test-1') {
                  steps {
                      snDevOpsChange()
                      // 'UAT test-1' tasks
                  }
                    post {
                      success {
                        // post success tasks. E.g.: junit '**/target/surefire-reports/*.xml'
                      }
                  }
              }
              stage('UAT static code test') {
                  steps {
                      snDevOpsChange()
                      // 'UAT static code test' tasks
                  }
              }
          }
     }