Smoke test packaged Linux AppImage in release CI

.github/workflows/release.yml

@@ -10,7 +10,7 @@ on:
   push:
     tags: ["v*"]
   pull_request:
-    paths: ["app/**", "desktop/**", "mac/frame-mac-view/**", ".github/workflows/release.yml"]
+    paths: ["app/**", "desktop/**", "mac/frame-mac-view/**", "scripts/check-appimage-launch.py", ".github/workflows/release.yml"]
   workflow_dispatch:
 
 # A newer push to the same pull request supersedes a build still in progress.
@@ -110,6 +110,9 @@ jobs:
         run: npm ci && npm run ${{ matrix.script }}
         env:
           CSC_IDENTITY_AUTO_DISCOVERY: "false"
+      - name: Launch the built Linux AppImage
+        if: matrix.os == 'ubuntu-latest'
+        run: python3 scripts/check-appimage-launch.py app/dist/Frame-Control-linux-x86_64.AppImage
       # The installer, not just the unpacked build: its 7-Zip payload once dropped
       # the OpenXR layer's arm64 library without any error. Install it silently
       # and compare every installed file with the unpacked build.

docs/releasing.md

@@ -20,6 +20,10 @@ count. So a build reaches people only when you publish it, after testing it.
    GitHub temporarily show its tag as `untagged-…`. The workflow finds that
    draft by its exact version title, restores the tag association and retries
    the affected upload; it refuses ambiguous matches.
+   The Linux build runs `scripts/check-appimage-launch.py` before upload. It
+   starts the built x86_64 AppImage on an isolated Xvfb display, checks that
+   its bundled server answers, and checks that the server stops on exit. This
+   CI test does not test a physical display, FUSE mount or a headset.
 
 2. Download the draft's installers and test them. An installed copy of the
    previous version won't offer the draft, so install it directly.

scripts/check-appimage-launch.py

@@ -0,0 +1,110 @@
+#!/usr/bin/env python3
+"""Launch a built Linux AppImage on Xvfb and check its bundled server.
+
+This checks the packaged app without a headset or a desktop login session.
+The profile and display are temporary, and every process started by this check
+is stopped before it exits.
+"""
+
+import hashlib
+import os
+from pathlib import Path
+import re
+import shutil
+import signal
+import socket
+import subprocess
+import sys
+import tempfile
+import time
+import urllib.error
+import urllib.request
+
+
+def server_port(profile):
+    for log in (profile / "config").rglob("server.log"):
+        ports = re.findall(r"--port (\d+)", log.read_text(errors="replace"))
+        if ports:
+            return int(ports[-1])
+    return None
+
+
+def port_closed(port):
+    try:
+        with socket.create_connection(("127.0.0.1", port), timeout=1):
+            return False
+    except OSError:
+        return True
+
+
+def check(appimage):
+    if not appimage.is_file() or not os.access(appimage, os.X_OK):
+        raise RuntimeError(f"AppImage is missing or cannot run: {appimage}")
+    if not shutil.which("xvfb-run"):
+        raise RuntimeError("xvfb-run is required for the AppImage smoke check")
+    digest = hashlib.sha256(appimage.read_bytes()).hexdigest()
+    with tempfile.TemporaryDirectory(prefix="frame-appimage-smoke-") as directory:
+        profile = Path(directory)
+        env = dict(os.environ)
+        env.update(
+            APPIMAGE_EXTRACT_AND_RUN="1", ELECTRON_DISABLE_SANDBOX="1",
+            XDG_CONFIG_HOME=str(profile / "config"),
+            XDG_CACHE_HOME=str(profile / "cache"),
+            XDG_DATA_HOME=str(profile / "data"),
+            FRAME_ALIAS="frame-control-appimage-smoke-no-headset",
+        )
+        output = profile / "app.log"
+        port = None
+        passed = False
+        with output.open("w") as log:
+            proc = subprocess.Popen(
+                ["xvfb-run", "-a", "-s", "-screen 0 1280x800x24 -nolisten tcp",
+                 str(appimage), "--no-sandbox"],
+                cwd=profile, env=env, stdout=log, stderr=subprocess.STDOUT,
+                start_new_session=True,
+            )
+            try:
+                deadline = time.monotonic() + 60
+                while time.monotonic() < deadline:
+                    if proc.poll() is not None:
+                        raise RuntimeError(f"AppImage exited {proc.returncode} before its server answered")
+                    port = server_port(profile)
+                    if port is not None:
+                        try:
+                            with urllib.request.urlopen(f"http://127.0.0.1:{port}/", timeout=2) as response:
+                                if response.status == 200 and response.headers.get("Server", "").startswith("FrameControl/1"):
+                                    passed = True
+                                    break
+                        except (OSError, urllib.error.URLError):
+                            pass
+                    time.sleep(0.5)
+                if not passed:
+                    raise RuntimeError("AppImage server did not answer within 60 seconds")
+            except BaseException:
+                log.flush()
+                print(output.read_text(errors="replace")[-1500:], file=sys.stderr)
+                raise
+            finally:
+                try:
+                    os.killpg(proc.pid, signal.SIGTERM)
+                except ProcessLookupError:
+                    pass
+                try:
+                    proc.wait(timeout=15)
+                except subprocess.TimeoutExpired:
+                    os.killpg(proc.pid, signal.SIGKILL)
+                    proc.wait(timeout=10)
+        if port is not None:
+            for _ in range(20):
+                if port_closed(port):
+                    break
+                time.sleep(0.5)
+            else:
+                raise RuntimeError(f"AppImage server stayed on port {port} after shutdown")
+    print(f"AppImage SHA-256 {digest}: HTTP 200, FrameControl/1, server stopped")
+
+
+if __name__ == "__main__":
+    if len(sys.argv) != 2:
+        raise SystemExit("usage: check-appimage-launch.py path/to/AppImage")
+    check(Path(sys.argv[1]).resolve())