refactor: Enhance health check logic to separate HTTP and systemd checks for clarity and maintainability

castle-api/src/castle_api/health.py

@@ -13,23 +13,34 @@ from castle_api.models import HealthStatus
 
 
 async def check_all_health(registry: NodeRegistry) -> list[HealthStatus]:
-    """Check health of all deployed components with a port and health_path."""
-    targets: list[tuple[str, str]] = []
+    """Check health of all deployed components.
+
+    Services with a port + health_path are checked via HTTP.
+    Managed services without an HTTP health endpoint fall back to systemd unit status.
+    """
+    http_targets: list[tuple[str, str]] = []
+    systemd_targets: list[str] = []
+
     for name, deployed in registry.deployed.items():
-        if not deployed.port or not deployed.health_path:
-            continue
-        url = f"http://127.0.0.1:{deployed.port}{deployed.health_path}"
-        targets.append((name, url))
-
-    if not targets:
-        return []
+        if deployed.port and deployed.health_path:
+            url = f"http://127.0.0.1:{deployed.port}{deployed.health_path}"
+            http_targets.append((name, url))
+        elif deployed.managed and not deployed.schedule:
+            # Managed service with no HTTP health endpoint — use systemd
+            systemd_targets.append(name)
 
+    tasks: list[asyncio.Task[HealthStatus]] = []
     async with httpx.AsyncClient(timeout=3.0) as client:
-        tasks = [_check_one(client, name, url) for name, url in targets]
-        return await asyncio.gather(*tasks)
+        for name, url in http_targets:
+            tasks.append(asyncio.ensure_future(_check_http(client, name, url)))
+        for name in systemd_targets:
+            tasks.append(asyncio.ensure_future(_check_systemd(name)))
+        if not tasks:
+            return []
+        return list(await asyncio.gather(*tasks))
 
 
-async def _check_one(client: httpx.AsyncClient, name: str, url: str) -> HealthStatus:
+async def _check_http(client: httpx.AsyncClient, name: str, url: str) -> HealthStatus:
     """Check a single service's health endpoint."""
     start = time.monotonic()
     try:
@@ -41,3 +52,16 @@ async def _check_one(client: httpx.AsyncClient, name: str, url: str) -> HealthSt
     except httpx.HTTPError:
         latency = int((time.monotonic() - start) * 1000)
         return HealthStatus(id=name, status="down", latency_ms=latency)
+
+
+async def _check_systemd(name: str) -> HealthStatus:
+    """Check a managed service's health via its systemd unit state."""
+    unit = f"castle-{name}.service"
+    proc = await asyncio.create_subprocess_exec(
+        "systemctl", "--user", "is-active", unit,
+        stdout=asyncio.subprocess.PIPE,
+        stderr=asyncio.subprocess.PIPE,
+    )
+    stdout, _ = await proc.communicate()
+    state = (stdout or b"").decode().strip()
+    return HealthStatus(id=name, status="up" if state == "active" else "down")