Attaching a generated file to a GitHub release using Actions#

For Datasette Desktop I wanted to run an action which, when I created a release, would build an asset for that release and then upload and attach it.

I triggered my action on the creation of a new release, like so:

1
on:
2
  release:
3
    types: [created]

Assuming previous steps that create a file called app.zip in the root of the checkout, here’s the final action step which worked for me:

1
      - name: Upload release attachment
2
        uses: actions/github-script@v4
3
        with:
4
          script: |
5
            const fs = require('fs');
6
            const tag = context.ref.replace("refs/tags/", "");
7
            // Get release for this tag
8
            const release = await github.repos.getReleaseByTag({
9
              owner: context.repo.owner,
10
              repo: context.repo.repo,
11
              tag
12
            });
13
            // Upload the release asset
14
            await github.repos.uploadReleaseAsset({
15
              owner: context.repo.owner,
16
              repo: context.repo.repo,
17
              release_id: release.data.id,
18
              name: "app.zip",
19
              data: await fs.readFileSync("app.zip")
20
            });

It uses actions/github-script which provides a pre-configured octokit/rest.js client object.

The uploadReleaseAsset() method needs the owner, repo, release_id, name (filename) and the file data.

These are mostly available, with the exception of release_id. That can be derived for the current release based on the context.ref value - strip that down to just the tag, then use getReleaseByTag() to get a release object. release.data.id will then be the numeric release ID.

My full workflow is at https://github.com/simonw/datasette-app/blob/0.1.0/.github/workflows/release.yml