Skip the workflow if there is already one running

.github/workflows/build.yml

@@ -35,37 +35,43 @@ jobs:
         python -m pip install --upgrade pip setuptools wheel
         python -m pip install --user -r requirements.txt
 
-    - name: Show build queue
-      id: queue
+    - name: Check if we should run
+      id: check
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: |
-        python autobuild.py show --fail-on-idle
+        python autobuild.py should-run
         $skipBuild = ($LASTEXITCODE -ne 0)
         If ($skipBuild) {echo '::set-output name=skip-build::true'}
         exit 0
 
+    - name: Show build queue
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      run: |
+        python autobuild.py show
+
     - uses: msys2/setup-msys2@v2
-      if: steps.queue.outputs.skip-build != 'true'
+      if: steps.check.outputs.skip-build != 'true'
       with:
         msystem: MSYS
         update: true
         install: msys2-devel base-devel mingw-w64-x86_64-toolchain mingw-w64-i686-toolchain git
 
     - name: Check install
-      if: steps.queue.outputs.skip-build != 'true'
+      if: steps.check.outputs.skip-build != 'true'
       run: |
         msys2 -c 'pacman -Qkq'
 
     - name: Init git
-      if: steps.queue.outputs.skip-build != 'true'
+      if: steps.check.outputs.skip-build != 'true'
       shell: msys2 {0}
       run: |
         git config --global user.email 'ci@msys2.org'
         git config --global user.name 'MSYS2 Continuous Integration'
 
     - name: Process build queue
-      if: steps.queue.outputs.skip-build != 'true'
+      if: steps.check.outputs.skip-build != 'true'
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: |
@@ -76,6 +82,7 @@ jobs:
         python autobuild.py build "$MSYS2_ROOT" "$BUILD_ROOT"
 
     - name: Clean up assets
+      if: steps.check.outputs.skip-build != 'true'
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: |

autobuild.py

@@ -44,6 +44,7 @@ SKIP: List[str] = [
 
 
 REPO = "msys2/msys2-autobuild"
+WORKFLOW = "build"
 
 
 def timeoutgen(timeout: float) -> Callable[[], float]:
@@ -549,6 +550,35 @@ def get_packages_to_build() -> Tuple[
     return done, skipped, todo
 
 
+def get_workflow():
+    repo = get_repo()
+    for workflow in repo.get_workflows():
+        if workflow.name == WORKFLOW:
+            return workflow
+    else:
+        raise Exception("workflow not found:", WORKFLOW)
+
+
+def should_run(args: Any) -> None:
+    current_id = None
+    if "GITHUB_RUN_ID" in os.environ:
+        current_id = int(os.environ["GITHUB_RUN_ID"])
+
+    workflow = get_workflow()
+    runs = list(workflow.get_runs(status="in_progress"))
+    runs += list(workflow.get_runs(status="queued"))
+    for run in runs:
+        if current_id is not None and current_id == run.id:
+            # Ignore this run itself
+            continue
+        raise SystemExit(
+            f"Another workflow is currently running or has something queued: {run.html_url}")
+
+    done, skipped, todo = get_packages_to_build()
+    if not todo:
+        raise SystemExit("Nothing to build")
+
+
 def show_build(args: Any) -> None:
     done, skipped, todo = get_packages_to_build()
 
@@ -564,9 +594,6 @@ def show_build(args: Any) -> None:
         print(tabulate([(p["name"], bt, p["version"]) for (p, bt) in done],
                        headers=["Package", "Build", "Version"]))
 
-    if args.fail_on_idle and not todo:
-        raise SystemExit("Nothing to build")
-
 
 def show_assets(args: Any) -> None:
     repo = get_repo()
@@ -757,6 +784,10 @@ def main(argv: List[str]):
         "--fail-on-idle", action="store_true", help="Fails if there is nothing to do")
     sub.set_defaults(func=show_build)
 
+    sub = subparser.add_parser(
+        "should-run", help="Fails if the workflow shouldn't run", allow_abbrev=False)
+    sub.set_defaults(func=should_run)
+
     sub = subparser.add_parser(
         "show-assets", help="Show all staging packages", allow_abbrev=False)
     sub.set_defaults(func=show_assets)