Do not exit fabric-sync-app before apps are terminated

Author: arkq

examples/fabric-admin/scripts/fabric-sync-app.py

@@ -31,10 +31,7 @@ async def forward_f(prefix: bytes, f_in: asyncio.StreamReader,
 
     This function can optionally feed received lines to a callback function.
     """
-    while True:
-        line = await f_in.readline()
-        if not line:
-            break
+    while line := await f_in.readline():
         if cb is not None:
             cb(line)
         f_out.buffer.write(prefix)
@@ -68,11 +65,7 @@ async def forward_stdin(f_out: asyncio.StreamWriter):
     reader = asyncio.StreamReader()
     protocol = asyncio.StreamReaderProtocol(reader)
     await loop.connect_read_pipe(lambda: protocol, sys.stdin)
-    while True:
-        line = await reader.readline()
-        if not line:
-            # Exit on Ctrl-D (EOF).
-            sys.exit(0)
+    while line := await reader.readline():
         f_out.write(line)
         await f_out.drain()
 
@@ -206,12 +199,16 @@ async def main(args):
             passcode=args.passcode,
         ))
 
+    loop = asyncio.get_event_loop()
+
     def terminate():
-        admin.terminate()
-        bridge.terminate()
-        sys.exit(0)
+        with contextlib.suppress(ProcessLookupError):
+            admin.terminate()
+        with contextlib.suppress(ProcessLookupError):
+            bridge.terminate()
+        loop.remove_signal_handler(signal.SIGINT)
+        loop.remove_signal_handler(signal.SIGTERM)
 
-    loop = asyncio.get_event_loop()
     loop.add_signal_handler(signal.SIGINT, terminate)
     loop.add_signal_handler(signal.SIGTERM, terminate)
 
@@ -238,7 +235,8 @@ def terminate():
             cmd,
             # Wait for the log message indicating that the bridge has been
             # added to the fabric.
-            f"Commissioning complete for node ID {bridge_node_id:#018x}: success")
+            f"Commissioning complete for node ID {bridge_node_id:#018x}: success",
+            timeout=30)
 
     # Open commissioning window with original setup code for the bridge.
     cw_endpoint_id = 0
@@ -250,18 +248,23 @@ def terminate():
                      f" {cw_option} {cw_timeout} {cw_iteration} {cw_discriminator}")
 
     try:
-        await asyncio.gather(
-            forward_pipe(pipe, admin.p.stdin) if pipe else forward_stdin(admin.p.stdin),
-            admin.wait(),
-            bridge.wait(),
-        )
-    except SystemExit:
-        admin.terminate()
-        bridge.terminate()
-    except Exception:
-        admin.terminate()
-        bridge.terminate()
-        raise
+        forward = forward_pipe(pipe, admin.p.stdin) if pipe else forward_stdin(admin.p.stdin)
+        # Wait for any of the tasks to complete.
+        _, pending = await asyncio.wait([
+            asyncio.create_task(admin.wait()),
+            asyncio.create_task(bridge.wait()),
+            asyncio.create_task(forward),
+        ], return_when=asyncio.FIRST_COMPLETED)
+        # Cancel the remaining tasks.
+        for task in pending:
+            task.cancel()
+    except Exception as e:
+        print(e, file=sys.stderr)
+
+    terminate()
+    # Make sure that we will not return until both processes are terminated.
+    await admin.wait()
+    await bridge.wait()
 
 
 if __name__ == "__main__":