Allow building PR images on demand (#340)

Triggered when the label is set in a PR.
Helps to test changes in PRs.

Co-authored-by: crapStone <codeberg@crapstone.dev>
Reviewed-on: https://codeberg.org/Codeberg/pages-server/pulls/340
Reviewed-by: crapStone <codeberg@crapstone.dev>
Co-authored-by: pat-s <patrick.schratz@gmail.com>
Co-committed-by: pat-s <patrick.schratz@gmail.com>

.woodpecker/build.yml

@@ -114,6 +114,23 @@ steps:
       - event: ['push']
         branch: ${CI_REPO_DEFAULT_BRANCH}
 
+  'Publish PR image':
+    image: woodpeckerci/plugin-docker-buildx:3.2.1
+    depends_on: test
+    settings:
+      registry: codeberg.org
+      dockerfile: Dockerfile
+      platforms: linux/amd64
+      repo: codeberg.org/codeberg/pages-server
+      tags: next
+      username:
+        from_secret: bot_user
+      password:
+        from_secret: bot_token
+    when:
+      evaluate: 'CI_COMMIT_PULL_REQUEST_LABELS contains "build_pr_image"'
+      event: pull_request
+
   docker-tag:
     depends_on: vendor
     image: woodpeckerci/plugin-docker-buildx:3.2.1

README.md

@@ -64,6 +64,9 @@ but forward the requests on the IP level to the Pages Server.
 You can check out a proof of concept in the `examples/haproxy-sni` folder,
 and especially have a look at [this section of the haproxy.cfg](https://codeberg.org/Codeberg/pages-server/src/branch/main/examples/haproxy-sni/haproxy.cfg#L38).
 
+If you want to test a change, you can open a PR and ask for the label `build_pr_image` to be added.
+This will trigger a build of the PR which will build a docker image to be used for testing.
+
 ### Environment Variables
 
 - `HOST` & `PORT` (default: `[::]` & `443`): listen address.