[CI] Add check for draft PRs (#5800)

* Add check for draft PRs

* Add necessary gitlab-ci boilerplate

* fix github API url (oops!)

* Add github action to retrigger pipeline

* fix workflow trigger

* rename trigger job

Co-authored-by: Benjamin Kampmann <ben@parity.io>

substrate/.github/workflows/trigger-review-pipeline.yml

@@ -0,0 +1,20 @@
+name: Trigger pipeline for review
+
+on:
+  pull_request:
+    types: [ready_for_review]
+
+jobs:
+  trigger:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Trigger pipeline
+        run: |
+          curl -X POST \
+            -F token="$TOKEN" \
+            -F ref="$REF" \
+            https://gitlab.parity.io/api/v4/projects/145/trigger/pipeline
+        env:
+          REF: ${{ github.event.number }}
+          TOKEN: ${{ secrets.GITLAB_TRIGGER_TOKEN }}

substrate/.gitlab-ci.yml

@@ -89,7 +89,16 @@ variables:
     - /^pre-v[0-9]+\.[0-9]+-[0-9a-f]+$/
     - web
 
+#### stage:                       .pre
 
+skip-if-draft:
+  image:                           parity/tools:latest
+  <<:                              *kubernetes-build
+  stage:                          .pre
+  only:
+    - /^[0-9]+$/                  # Pull requests
+  script:
+     - ./.maintain/gitlab/skip_if_draft.sh
 
 #### stage:                        test
 

substrate/.maintain/gitlab/skip_if_draft.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+url="https://api.github.com/repos/paritytech/substrate/pulls/${CI_COMMIT_REF_NAME}"
+echo "[+] API URL: $url"
+
+draft_state=$(curl "$url" | jq -r .draft)
+echo "[+] Draft state: $draft_state"
+
+if [ "$draft_state" = 'true' ]; then
+  echo "[!] PR is currently a draft, stopping pipeline"
+  exit 1
+else
+  echo "[+] PR is not a draft. Proceeding with CI pipeline"
+  exit 0
+fi