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  1. Jenkins
  2. JENKINS-55315

Obtain target changelist from PerforceScm object in pipeline

    • Icon: New Feature New Feature
    • Resolution: Unresolved
    • Icon: Major Major
    • p4-plugin

      We have a multibranch pipeline which after being triggered immediately splits into 6 stages for various linux and windows platforms. The sequence of each of the pipelines goes like this:

      • Obtain branch source (checkout scm)
      • Obtain platform specific thirdparties (p4sync)
      • Obtain common thirdparties (p4sync)
      • Build/Test/Archive/Etc

      The problem I am having is pinning the thirdparty syncs to the same changelist as the branch, because each instance of a sync can set the P4_CHANGELIST environment variable (which seems to be updated globally) to a different value, so unless I perform a single sync ahead of all the others just to get the changelist and store it, I have a race condition.

      What I would like to do is be able to put this at the start of my script, before I enter the pipeline block:

      env.GLOBAL_P4_CHANGELIST = scm.getChangelist()
      

      Which would ensure I have a global reference to the changelist that triggered the build to use for pinning the subsequent thirdparty syncs,  that isn't overridden by any subsequent uses of p4sync.

      I see that PerforceScm has a property P4Ref revision. Can this be exposed in the manner I'd like?

       

      My current workaround consists of either wrapping an initial checkout in a lock step so that I can set the global variable after a first sync has completed (this delays all other parallel stages by the time it takes to sync, which can be up to 10 minutes currently)

      lock("$env.JOB_NAME-GLOBAL_P4_CHANGELIST"){
          if ( !env.GLOBAL_P4_CHANGELIST ){
              checkout scm
              env.GLOBAL_P4_CHANGELIST = "$env.P4_CHANGELIST"
              env.GLOBAL_P4_CHANGELIST_STAGE = "$env.STAGE_NAME"
          }
          echo "GLOBAL_P4_CHANGELIST = $env.GLOBAL_P4_CHANGELIST"
          echo "GLOBAL_P4_CHANGELIST_STAGE = $env.GLOBAL_P4_CHANGELIST_STAGE"
      }
      if ( ! (env.STAGE_NAME == $env.GLOBAL_P4_CHANGELIST_STAGE) ){
          checkout scm
      }
      

      or by trying to use a lock on updating the variable immediately after a checkout scm, which still has a race condition.

          [JENKINS-55315] Obtain target changelist from PerforceScm object in pipeline

          Karl Wirth added a comment -

          Hi alisdair_robertson,

          Thanks for the suggestion. I can see that this would be useful so I will discuss with the developers.

          Karl Wirth added a comment - Hi alisdair_robertson , Thanks for the suggestion. I can see that this would be useful so I will discuss with the developers.

          Karl Wirth added a comment -

          There are a couple of ways to approach this. A temporary workaround for now is to cache the highest changelist across the depot (or part) instead of the sync mentioned above.

          For example:

            def ws = [$class: 'StreamWorkspaceImpl', 
                  charset: 'none', format: env.JOB_NAME + '-get-CL', pinHost: false, 
                  streamName: '//streams/main']
          
              // Create P4 object
              def p4 = p4(credential: 'JenkinsMaster', workspace: ws)
          
              def Result = p4.run('changes','-m1','//...')
              GLOBAL_CHANGELIST = Result[0].change;
          

          However we also see merrit in the plugin doing this so I'm passing it onto the developers.

          Karl Wirth added a comment - There are a couple of ways to approach this. A temporary workaround for now is to cache the highest changelist across the depot (or part) instead of the sync mentioned above. For example: def ws = [$class: 'StreamWorkspaceImpl' , charset: 'none' , format: env.JOB_NAME + '-get-CL' , pinHost: false , streamName: ' //streams/main' ] // Create P4 object def p4 = p4(credential: 'JenkinsMaster' , workspace: ws) def Result = p4.run( 'changes' , '-m1' , ' //...' ) GLOBAL_CHANGELIST = Result[0].change; However we also see merrit in the plugin doing this so I'm passing it onto the developers.

            Unassigned Unassigned
            alisdair_robertson Alisdair Robertson
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              Created:
              Updated: