fix: Remove redundant output redirect from parent process

RAPID wires the runtime main process's stdout/stderr to the log egress
at spawn, so the parent does not need to dial the telemetry FD provider
socket — that socket exists for the forked workers, which continue to
redirect in run_single. Addresses PR review feedback.

Author: vip-amzn

awslambdaric/lambda_multi_concurrent_utils.py

@@ -36,10 +36,13 @@ def run_single(
         bootstrap.run(handler, client)
 
     @classmethod
-    def _emit_worker_pool_event(cls, socket_path: str, max_concurrency: int):
-        """Emit worker pool DEBUG event once from the parent before forking."""
-        if socket_path:
-            cls._redirect_output(socket_path)
+    def _emit_worker_pool_event(cls, max_concurrency: int):
+        """Emit worker pool DEBUG event once from the parent before forking.
+
+        No output redirection here: RAPID wires the runtime main process's
+        stdout/stderr to the log egress at spawn. The FD provider socket is
+        only for the forked workers, which redirect in run_single.
+        """
         log_sink = bootstrap.init_logging()
         logging.getLogger().debug(
             {
@@ -62,7 +65,7 @@ def run_concurrent(
         socket_path: str,
         max_concurrency: int,
     ):
-        cls._emit_worker_pool_event(socket_path, max_concurrency)
+        cls._emit_worker_pool_event(max_concurrency)
 
         processes = []
         for _ in range(max_concurrency):

tests/test_multi_concurrent_runner.py

@@ -94,18 +94,19 @@ def test_run_concurrent_emits_worker_pool_event_once_before_spawning(
                 "h", "a", False, "/sock", max_concurrency=3
             )
 
-        mock_emit.assert_called_once_with("/sock", 3)
-        self.assertEqual(order_tracker.mock_calls[0], call.emit("/sock", 3))
+        mock_emit.assert_called_once_with(3)
+        self.assertEqual(order_tracker.mock_calls[0], call.emit(3))
 
     @patch("awslambdaric.lambda_multi_concurrent_utils.logging")
     @patch("awslambdaric.lambda_multi_concurrent_utils.bootstrap")
     def test_emit_worker_pool_event_sets_up_parent_logging_and_emits(
         self, mock_bootstrap, mock_logging
     ):
         with patch.object(MultiConcurrentRunner, "_redirect_output") as mock_redirect:
-            MultiConcurrentRunner._emit_worker_pool_event("/sock", 16)
+            MultiConcurrentRunner._emit_worker_pool_event(16)
 
-        mock_redirect.assert_called_once_with("/sock")
+        # Parent never redirects: RAPID wires its stdout at spawn.
+        mock_redirect.assert_not_called()
         mock_bootstrap.init_logging.assert_called_once_with()
         mock_logging.getLogger.return_value.debug.assert_called_once()
         event = mock_logging.getLogger.return_value.debug.call_args[0][0]
@@ -117,18 +118,6 @@ def test_emit_worker_pool_event_sets_up_parent_logging_and_emits(
             None, None, None
         )
 
-    @patch("awslambdaric.lambda_multi_concurrent_utils.logging")
-    @patch("awslambdaric.lambda_multi_concurrent_utils.bootstrap")
-    def test_emit_worker_pool_event_skips_redirect_when_no_socket(
-        self, mock_bootstrap, mock_logging
-    ):
-        with patch.object(MultiConcurrentRunner, "_redirect_output") as mock_redirect:
-            MultiConcurrentRunner._emit_worker_pool_event(None, 4)
-
-        mock_redirect.assert_not_called()
-        mock_bootstrap.init_logging.assert_called_once_with()
-        mock_logging.getLogger.return_value.debug.assert_called_once()
-
     @patch(
         "awslambdaric.lambda_multi_concurrent_utils.LambdaMultiConcurrentRuntimeClient"
     )