From: Sven Trenkel <collectd@semidefinite.de>
Date: Wed, 21 Apr 2010 16:26:55 +0000 (+0200)
Subject: python: Added documentation and an example on how to handle SIGCHLD.
X-Git-Tag: collectd-4.10.0~16^2
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=690836d783193c76cd815b96e173b028574c3fce;p=collectd.git

python: Added documentation and an example on how to handle SIGCHLD.
---

diff --git a/contrib/python/getsigchld.py b/contrib/python/getsigchld.py
new file mode 100644
index 00000000..557adc09
--- /dev/null
+++ b/contrib/python/getsigchld.py
@@ -0,0 +1,21 @@
+#!/usr/bin/python
+
+###############################################################################
+#         WARNING! Importing this script will break the exec plugin!          #
+###############################################################################
+# Use this if you want to create new processes from your python scripts.      #
+# Normally you will get a OSError exception when the new process terminates   #
+# because collectd will ignore the SIGCHLD python is waiting for.             #
+# This script will restore the default SIGCHLD behavior so python scripts can #
+# create new processes without errors.                                        #
+###############################################################################
+#         WARNING! Importing this script will break the exec plugin!          #
+###############################################################################
+
+import signal
+import collectd
+
+def init():
+	signal.signal(signal.SIGCHLD, signal.SIG_DFL)
+
+collectd.register_init(init)
diff --git a/src/collectd-python.pod b/src/collectd-python.pod
index 05a411cc..dd0f1f68 100644
--- a/src/collectd-python.pod
+++ b/src/collectd-python.pod
@@ -105,6 +105,15 @@ environment variable, e.g. I<export PAGER=less> before starting collectd.
 Depending on your version of python this might or might not result in an
 B<OSError> exception which can be ignored.
 
+If you really need to spawn new processes from python you can register an init
+callback and reset the action for SIGCHLD to the default behavior. Please note
+that this I<will> break the exec plugin. Do not even load the exec plugin if
+you intend to do this!
+
+There is an example script located in B<contrib/python/getsigchld.py>  to do
+this. If you import this from I<collectd.conf> SIGCHLD will be handled
+normally and spawning processes from python will work as intended.
+
 =back
 
 =item E<lt>B<Module> I<Name>E<gt> block