concourse / concourse/pool-resource

Releasing lock ignores metadata

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Dominant language
Go
Stars
59
Forks
39
PR merge metrics
No merged PRs in 30d

Description

I am trying to do an atomic update of metadata, and the update parameter does not help because I have to create or modify the metadata outside of the lock. Doing so would potentially cause the step to overwrite an update that happens after I get the lock to be able to modify it.

What I would like to do is this:

      - do:
          - put: environment_pool
            params:
              claim: environment-1

          - get: environment-1
            resource: environment_pool

          - task: update_metadata
            file: shared_tasks/update-metadata.yml
            input_mapping:
              environment: environment-1
              project_repo: my_application_repo
              build_version: my_application_version
            output_mapping:
              environment_out: environment_out
            params:
              APPLICATION_NAME: my_application

        ensure:
          put: environment_pool
          params:
            # This should(?) commit the metadata from environment_out
            release: environment_out

It seems like it would be a simple change to have UnclaimLock() take inDir as a parameter and do the mv command from there. However, I wonder if there are reasons for not doing it this way. Is there any other workaround I might use?

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading the UnclaimLock() implementation and the lock-release flow. Trace how the shown get/task/ensure sequence handles environment_out and metadata, then determine whether release can commit it without overwriting a later update. Done means the atomic metadata behavior and any supported workaround are documented by tests or clearly resolved.

Written by the indexing model from the issue text.

Assessment

Tech stack
go
Domain
devops
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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