Await remote workflow artifacts

A GitHub action to wait for named artifacts to become available in another workflow, and to optionally download them in the current workflow. Downloaded artifacts are unpacked into the nominated directory.

This can be useful when one workflow issues a repository_dispatch event to start a second workflow, and the first workflow creates artifacts needed in the second workflow.

In this situation, there is a race: The second workflow may start as soon as the first workflow issues the repository_dispatch event, but the artifacts do not become visible in the GitHub API until after the first workflow has finished. The second workflow might therefore need to wait for the artifacts to appear.

Example usage

Suppose we have a first workflow that uploads some artifacts, and then issues a repository_dispatch event:

name: First workflow

on:
  push:

jobs:
  workflow-1:
    name: First workflow job
    runs-on: ubuntu-latest
    steps:
      - name: Create some files
        run: |
          mkdir -p artifact-1/dir-1 artifact-2/dir-2
          echo hello > artifact-1/dir-1/file-1
          echo hello > artifact-2/dir-2/file-2
      - name: Upload artifact-1
        uses: actions/upload-artifact@v3
        with:
          name: artifact-1
          path: artifact-1
      - name: Upload artifact-2
        uses: actions/upload-artifact@v3
        with:
          name: artifact-2
          path: artifact-2
      - name: Issue repository-dispatch
        uses: peter-evans/repository-dispatch@v2
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          repository: ${{ github.repository }}
          event-type: my-event
          client-payload: |
            { "run_id": "${{ github.run_id }}" }
      - name: Sleep a while
        run: sleep 60

Notice that this first workflow sleeps for a minute after issuing the repository_dispatch event. This means that the artifacts will not immediately be visible in the GitHub API.

The first workflow passes its own run_id in the client-payload for the repository_dispatch event, so the second workflow can locate it.

Then, suppose we also have a second workflow in the same repository, that is triggered by the respository_dispatch event. We'll use this action to download the artifacts created in the first workflow:

name: Second workflow

on:
  repository_dispatch:
    types:
      - my-event

jobs:
  workflow-2:
    name: Second workflow job
    runs-on: ubuntu-latest
    steps:
      - name: Download artifacts
        uses: mbrcknl/await-remote-artifacts@v2
        with:
          repo: ${{ github.repository }}
          run-id: ${{ github.event.client_payload.run_id }}
          artifact-names: artifact-1 artifact-2
          token: ${{ secrets.GITHUB_TOKEN }}
          download-dir: artifacts
      - name: List downloaded artifacts
        run: |
          # List downloaded artifacts
          find artifacts -type f

Notice that artifacts are downloaded as zip files. Once unpacked, the find command in the last step produces the following output:

artifacts/artifact-1/dir-1/file-1
artifacts/artifact-2/dir-2/file-2

This action can also be used to download artifacts when the first and second workflows are in different repositories. However, in that case, you'll need to use tokens with appropriate access.

Known issues

• Artifacts are downloaded to memory before being saved to disk, so this may not work for large artifacts.
• The action currently makes no attempt to avoid GitHub API rate limits, so it might fail when the target workflow has many artifacts.