fail faster in integration test (reflex-dev#1493)

scripts/integration.sh

@@ -10,11 +10,20 @@ export PYTHONUNBUFFERED=1
 # Start the server in the background
 reflex run --loglevel debug --env "$2" & pid=$!
 
-# TODO does this even work on windows? Not clear, possibly not impactful though.
-trap "kill -INT $pid ||:" EXIT
+# Within the context of this bash, $pid_in_bash is what we need to pass to "kill" on exit
+# This is true on all platforms.
+pid_in_bash=$pid
+trap "kill -INT $pid_in_bash ||:" EXIT
 
 echo "Started server with PID $pid"
 
 # Assume we run from the root of the repo
 popd
+
+# In Windows, our Python script below needs to work with the WINPID
+if [ -f /proc/$pid/winpid ]; then
+  pid=$(cat /proc/$pid/winpid)
+  echo "Windows detected, passing winpid $pid to port waiter"
+fi
+
 python scripts/wait_for_listening_port.py 3000 8000 --timeout=600 --server-pid "$pid"

scripts/wait_for_listening_port.py

@@ -7,21 +7,36 @@
 import socket
 import time
 from concurrent.futures import ThreadPoolExecutor, as_completed
+from typing import Tuple
 
+# psutil is already a dependency of Reflex itself - so it's OK to use
+import psutil
 
-def _wait_for_port(port, server_pid, timeout):
+
+def _pid_exists(pid):
+    # os.kill(pid, 0) doesn't work on Windows (actually kills the PID)
+    # psutil.pid_exists() doesn't work on Windows (does os.kill underneath)
+    # psutil.pids() seems to return the right thing. Inefficient but doesn't matter - keeps things simple.
+    #
+    # Note: For windows, the pid here is really the "winpid".
+    return pid in psutil.pids()
+
+
+def _wait_for_port(port, server_pid, timeout) -> Tuple[bool, str]:
     start = time.time()
     print(f"Waiting for up to {timeout} seconds for port {port} to start listening.")
     while True:
-        # TODO fail early if server pid not there
+        if not _pid_exists(server_pid):
+            return False, f"Server PID {server_pid} is not running."
         try:
             socket.create_connection(("localhost", port), timeout=0.5)
-            print(f"OK! Port {port} is listening after {time.time() - start} seconds")
-            return True
+            return True, f"Port {port} is listening after {time.time() - start} seconds"
         except Exception:
             if time.time() - start > timeout:
-                print(f"FAIL: Port {port} still not listening after {timeout} seconds.")
-                return False
+                return (
+                    False,
+                    f"Port {port} still not listening after {timeout} seconds.",
+                )
             time.sleep(5)
 
 
@@ -39,8 +54,11 @@ def main():
             executor.submit(_wait_for_port, p, args.server_pid, args.timeout)
         )
     for f in as_completed(futures):
-        if not f.result():
-            print("At least one port failed... exiting with failure.")
+        ok, msg = f.result()
+        if ok:
+            print(f"OK: {msg}")
+        else:
+            print(f"FAIL: {msg}")
             exit(1)