python-Werkzeug/0001_create_a_thread_to_reap_death_process.patch

From 676bc5fa4b6aa9d153c9805cdbad0ff0450bade6 Mon Sep 17 00:00:00 2001
From: Alberto Planas <aplanas@gmail.com>
Date: Wed, 3 Feb 2016 11:56:23 +0100
Subject: [PATCH] Create a thread to reap death process

ForkingWSGIServer use `SocketServer.ForkingMixIn` to implement a
multiprocess server.  This class provides a workflow that collect
death process (process in Zombie status) before the
`process_request`.  This means that this process itself will be
in Zombie status at the end of the request, that will be eventually
collected during the next `process_request`.

To minimize transient Zombie process, `ForkingWSGIServer` is
creating a daemon thread (via `threading.Timer`) to call the
collector every (by default) 5 seconds.

Fixes #810
---
 werkzeug/serving.py | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

Index: Werkzeug-0.15.4/src/werkzeug/serving.py
===================================================================
--- Werkzeug-0.15.4.orig/src/werkzeug/serving.py
+++ Werkzeug-0.15.4/src/werkzeug/serving.py
@@ -41,6 +41,7 @@ import signal
 import socket
 import sys
 
+import threading
 import werkzeug
 from ._compat import PY2
 from ._compat import reraise
@@ -775,6 +776,7 @@ class ForkingWSGIServer(ForkingMixIn, Ba
         passthrough_errors=False,
         ssl_context=None,
         fd=None,
+        frequency=5,
     ):
         if not can_fork:
             raise ValueError("Your platform does not support forking.")
@@ -783,6 +785,23 @@ class ForkingWSGIServer(ForkingMixIn, Ba
         )
         self.max_children = processes
 
+        if frequency:
+            self.frequency = frequency
+            self.setup_reap_children()
+
+    def setup_reap_children(self):
+        """Create a thread to collect death children."""
+        t = threading.Timer(self.frequency, self.reap_children)
+        # Set daemon mode to provide a clean termination of the thread
+        # when the system ends
+        t.daemon = True
+        t.start()
+
+    def reap_children(self):
+        """Reap or collect death children."""
+        self.collect_children()
+        self.setup_reap_children()
+
 
 def make_server(
     host=None,