Azure DevOps: Script Caching in Azure DevOps

I’m authoring a release pipeline in Azure DevOps on an AWS ARM linux machine, I’ve installed the agent and created the script. The pipeline uses artifacts produced by another build pipeline and depends on a git repository that contains script. Here is how resources are declared in the pipeline.

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resources: 

  pipelines:
  - pipeline: UniqueHost
    source: Publish-UniqueHost
    branch: master

  repositories:
    - repository: JarvisSetupScripts
      type: git
      ref: feature/AWS
      name: JarvisSetupScripts

Usually the question is: why you store scripts in another repository?. The classic approach is writing release scripts inside the very same repository as source files, then include release script inside the build so release pipeline depends only on one or more pipeline. Personally having the script in a different repositories easy script authoring, because you can simply modify the script, push, and then immediately re-trigger the pipeline to verify that everything is working as expected.

Having script in a different repository allows for a faster development cycle.

The downside of this approach is that the script is not versioned with the source code, but you can easily include the script in the original repository once the script is stable.

Despite the various reason I’ve encountered a strange problem when I author the script for the first time in a linux machine. The problem is simple: I run the pipeline and found an error then I modify the script, push new version, run the pipeline and … I have the very same error. Looking at the logs it seems that the Git repository is not updated so the script uses the old version without the fix.

I do not know if this is a bug or something I’ve badly configured, but the net result is that the release is still using the old version of my script and this is clearly visible from the log, where I verified that indeed the repository is pointing to an old commit. A quick fix is including a script task before the checkout task that deletes the old script folder, so the checkout task is forced to download the latest version of the script.

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- script: |
    rm -rf $(Pipeline.Workspace)/JarvisSetupScripts    
  displayName: Deleting old script to avoid caching
  name: delete_old_scripts_prevent_caching

- checkout: JarvisSetupScripts
  fetchDepth: 1
  clean: true
  path: JarvisSetupScripts

I know that this is not a super clean approach, but this fixes all the problem for me, because now, whenever the checkout action runs it starts from an empty folder so it will download again everything, check out the folder, and always uses the latest version of the script.

Gian Maria.