File 0001_create_a_thread_to_reap_death_process.patch of Package python-Werkzeug-doc.33733

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-0.12.1/werkzeug/serving.py
===================================================================
--- Werkzeug-0.12.1.orig/werkzeug/serving.py
+++ Werkzeug-0.12.1/werkzeug/serving.py
@@ -41,6 +41,7 @@ import os
 import socket
 import sys
 import signal
+import threading
 
 
 can_fork = hasattr(os, "fork")
@@ -562,13 +563,31 @@ class ForkingWSGIServer(ForkingMixIn, Ba
     multiprocess = True
 
     def __init__(self, host, port, app, processes=40, handler=None,
-                 passthrough_errors=False, ssl_context=None, fd=None):
+                 passthrough_errors=False, ssl_context=None, fd=None,
+                 frequency=5):
         if not can_fork:
             raise ValueError('Your platform does not support forking.')
         BaseWSGIServer.__init__(self, host, port, app, handler,
                                 passthrough_errors, ssl_context, fd)
         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, port=None, app=None, threaded=False, processes=1,
                 request_handler=None, passthrough_errors=False,