GitHub Actions: Workaround For Runner Path Resolution Issue

by Alex Johnson 60 views

This article explains a temporary workaround used in a GitHub Action to address a path resolution issue in the GitHub Actions runner. This issue affects composite actions and how they reference internal modules. The workaround involves copying the action's files to a subdirectory to ensure correct path resolution. This article provides context around the issue, the workaround, and the eventual resolution.

Understanding the Issue: Path Resolution in Composite Actions

Composite actions in GitHub Actions allow you to bundle multiple steps into a reusable action. This promotes modularity and reduces duplication in your workflows. However, a path resolution issue can occur within composite actions, specifically when referencing files within the action's directory. The GitHub Actions runner might not correctly resolve paths, leading to errors when executing steps that rely on these internal files.

The core problem lies in how the runner interprets relative paths within the action.yml file of a composite action. When an action uses other actions or scripts located in the same repository, it relies on correct path resolution to find those resources. If the runner doesn't resolve these paths correctly, it can lead to failures, especially when the action is used in different contexts or repositories.

This incorrect resolution typically manifests when the runner fails to locate necessary scripts or modules within the action's directory, causing the workflow to halt. This can be particularly frustrating as the action might work perfectly fine in some environments but fail in others due to subtle differences in the execution context.

Addressing this requires a deeper understanding of how the GitHub Actions runner handles path resolution for composite actions and implementing workarounds to ensure that the necessary files are correctly located during workflow execution. This is particularly important for actions designed to be reusable across multiple projects, where consistent and reliable behavior is paramount.

The Workaround: Copying Action Files

The workaround implemented in this action involves copying all files from the action's root directory to a subdirectory named self-test-action. This ensures that all subsequent steps within the action can correctly reference the necessary files using relative paths within this new subdirectory.

The following snippet from the action.yml file demonstrates the implementation of this workaround:

- shell: bash
  # FIXME: workaround until will be merged: https://github.com/actions/runner/pull/1684
  run: mkdir -p ./self-test-action/ && cp -r $GITHUB_ACTION_PATH/../* ./self-test-action/

Here's a breakdown of what this code does:

  1. mkdir -p ./self-test-action/: This command creates a new directory named self-test-action if it doesn't already exist. The -p flag ensures that parent directories are also created if needed.
  2. cp -r $GITHUB_ACTION_PATH/../* ./self-test-action/: This command copies all files and directories from the action's root directory (obtained using $GITHUB_ACTION_PATH/../*) to the newly created self-test-action directory. The -r flag ensures that the copy is recursive, preserving the directory structure.

By copying the files to this subdirectory, the action ensures that all subsequent steps, such as the setup-node and get-package-manager actions, can correctly reference the necessary files using relative paths within the self-test-action directory. For example:

- id: setup-node
  if: inputs.container != 'true'
  uses: ./self-test-action/setup-node
  with:
    working-directory: ${{ inputs.working-directory }}
    dependencies-cache: |
      nx
      jest

This ensures that the setup-node action, which is located within the self-test-action directory, is correctly executed with the specified working directory and dependencies cache.

This workaround addresses the path resolution issue by providing a consistent and reliable way to reference files within the action, regardless of the execution context.

Impacted Sections of the Action

The workaround primarily impacts the sections of the action that rely on internal modules or scripts located within the action's directory. This includes:

  • setup-node: This step, responsible for setting up the Node.js environment, relies on files within the action's directory to configure the environment correctly.
  • get-package-manager: This step, responsible for determining the appropriate package manager to use, also relies on files within the action's directory to identify the package manager.

By copying the action's files to the self-test-action directory, the workaround ensures that these steps can correctly locate and execute the necessary files, regardless of the path resolution issue.

The Pending Pull Request: A Permanent Solution

The workaround described above is a temporary solution to address the path resolution issue. A permanent solution is being developed in the form of a pull request to the GitHub Actions runner (https://github.com/actions/runner/pull/1684).

Once this pull request is merged and the GitHub Actions runner is updated, the path resolution issue will be resolved, and the workaround will no longer be necessary. This will simplify the action's implementation and make it more robust.

The pull request aims to fix the underlying issue in the runner, ensuring that relative paths within composite actions are correctly resolved without the need for workarounds. This will improve the overall reliability and consistency of GitHub Actions, making it easier to create and use reusable actions.

Removing the Workaround

Once the pull request is merged and the GitHub Actions runner is updated, the workaround can be safely removed from the action. This involves removing the following lines from the action.yml file:

- shell: bash
  # FIXME: workaround until will be merged: https://github.com/actions/runner/pull/1684
  run: mkdir -p ./self-test-action/ && cp -r $GITHUB_ACTION_PATH/../* ./self-test-action/

Additionally, all references to the self-test-action directory in subsequent steps should be removed. For example, the uses property in the setup-node step should be changed from ./self-test-action/setup-node to ./setup-node.

Removing the workaround will simplify the action's implementation and make it more maintainable. It will also ensure that the action is using the latest and most efficient path resolution mechanism provided by the GitHub Actions runner.

Conclusion

This article has explained a temporary workaround used in a GitHub Action to address a path resolution issue in the GitHub Actions runner. The workaround involves copying the action's files to a subdirectory to ensure correct path resolution. A permanent solution is being developed in the form of a pull request to the GitHub Actions runner, which will eventually eliminate the need for this workaround. By understanding the issue, the workaround, and the eventual resolution, you can better understand the intricacies of GitHub Actions and how to create robust and reusable actions. For more information on GitHub Actions and composite actions, refer to the official GitHub Actions documentation.