Support liveness endpoint (#161)

* support liveness endpoint

* Fix linter

imjoy/VERSION

@@ -1,3 +1,3 @@
 {
-    "version": "0.11.10"
+    "version": "0.11.11"
 }

imjoy/server.py

@@ -12,6 +12,8 @@
 from fastapi import FastAPI
 from fastapi.logger import logger
 from fastapi.middleware.cors import CORSMiddleware
+from starlette.requests import Request
+from starlette.responses import JSONResponse
 
 from imjoy import __version__ as VERSION
 from imjoy.core import (
@@ -79,6 +81,11 @@ async def connect(sid, environ):
         all_users[uid]._sessions.append(sid)
         all_sessions[sid] = all_users[uid]
 
+    @sio.event
+    async def echo(sid, data):
+        """Echo service for testing."""
+        return data
+
     @sio.event
     async def register_plugin(sid, config):
         user_info = all_sessions[sid]
@@ -241,6 +248,22 @@ def setup_socketio_server(
     app.sio = sio
     core_api = CoreInterface()
     initialize_socketio(sio, core_api)
+
+    @app.get("/liveness")
+    async def liveness(req: Request) -> JSONResponse:
+        try:
+            loop = asyncio.get_event_loop()
+            fut = loop.create_future()
+
+            def done():
+                fut.set_result()
+
+            await sio.emit("liveness", callback=done)
+            await fut
+        except Exception:  # pylint: disable=broad-except
+            return JSONResponse({"status": "DOWN"}, status_code=503)
+        return JSONResponse({"status": "OK"})
+
     return sio
 
 

tests/test_imjoy_engine_server.py

@@ -23,10 +23,10 @@ def socketio_server_fixture():
         [sys.executable, "-m", "imjoy.server", f"--port={PORT}"]
     ) as proc:
 
-        timeout = 5
+        timeout = 10
         while timeout > 0:
             try:
-                response = requests.get(f"http://127.0.0.1:{PORT}/")
+                response = requests.get(f"http://127.0.0.1:{PORT}/liveness")
                 if response.ok:
                     break
             except RequestException: