Preview PRs in github.io

[juancho0202]

As a stakeholder of the open-scd project I would like to test functional behavior of the PRs in a temporary URL which features a copy of OpenSCD made with the code in the branch of the pull request.

Acceptance Criteria:

• A github workflow is added (runs on pull_request) which builds and deploys OpenSCD to a custom URL

[juancho0202]

There is a small chance that in the future we can count on an official github-pages solution for this https://github.com/actions/deploy-pages/pull/61

[trusz]

The pull request with the GitHub Action to generate a preview has been already merged:

• https://github.com/openscd/open-scd/pull/1547

It currently deploys the wrong folder here: https://github.com/openscd/open-scd/blob/main/.github/workflows/pr-preview.yml#L33

I've already fixed it. It needs to deploy from /packages/distribution/build.

The next problem is that OpenSCD ist deployed under a path like .../pr-preview/pr-4/ and it should load files from this subfolder but it tries to load the files from the root.

The next step to set a base URL at build time so it loads the correct files.

[trusz]

The solution is make the referenced files' path adjustable. With snowpack we can set the base URL: buildOptions.baseUrl Then we can use %PUBLIC_URL% to reference files:

- <script type="module" src="/main.js"></script>
+ <script type="module" src="%PUBLIC_URL%/main.js"></script>

To change this from the outside we can configure snowpack in snowpack.config.mjs like this:

  buildOptions: {
    baseUrl: process.env.PUBLIC_URL || '/',
  },

and set the path in when we start the build process eg.: PUBLIC_URL=open-scd/pr-preview/pr-1 npm run-script build

the reference to built-in plug-ins in plugins.ts we can figure out dynamically dependent on where OpenSCD is deployed:

const path = location.origin + location.pathname + plugin

The next step is to fix the failing tests, because of the changed plugin paths.

[trusz]

The tests were failing because the pluginIds in the tests were still relative paths but OpenSCD now generates absolute paths and OpenSCD could not find them in local storage.

[trusz]

The final problem was that GitHub Pages, by default, does not server files from folders that start with _. It has something to do with jekyll, but it was an easy fix because you can disable jekyll with a .nojekyll file at root level.