From: Sven Velt <sven@velt.de>
Date: Tue, 27 Jul 2010 11:57:42 +0000 (+0200)
Subject: Add timeout to plugin execution
X-Git-Url: https://git.tokkee.org/?p=nagixsc.git;a=commitdiff_plain;h=8df1882e9db666887a5b97ffb2befc969e904087

Add timeout to plugin execution

It's now possible to terminate plugins after a few seconds. Just set
"plugin_timeout" and maybe "plugin_timeout_returncode" in "[nagixsc]"
section in the conf file. Sample config "timeout.conf" included in
"sample-configs/conf/".

Signed-off-by: Sven Velt <sven@velt.de>
---

diff --git a/nagixsc/__init__.py b/nagixsc/__init__.py
index 321407b..644c9ab 100644
--- a/nagixsc/__init__.py
+++ b/nagixsc/__init__.py
@@ -8,6 +8,7 @@ import mimetools
 import os
 import random
 import shlex
+import signal
 import socket
 import string
 import subprocess
@@ -20,6 +21,11 @@ def debug(level, verb, string):
 
 ##############################################################################
 
+class ExecTimeoutError(Exception):
+	pass
+
+##############################################################################
+
 def available_encodings():
 	return ['base64', 'plain',]
 
@@ -60,7 +66,10 @@ def read_inifile(inifile):
 
 ##############################################################################
 
-def exec_check(host_name, service_descr, cmdline):
+def exec_timeout_handler(signum, frame):
+	raise ExecTimeoutError
+
+def exec_check(host_name, service_descr, cmdline, timeout=None, timeout_returncode=2):
 	cmdarray = shlex.split(cmdline)
 
 	check = {}
@@ -72,13 +81,27 @@ def exec_check(host_name, service_descr, cmdline):
 		check['returncode'] = 127
 		return check
 
+	if timeout:
+		signal.signal(signal.SIGALRM, exec_timeout_handler)
+		signal.alarm(timeout)
+
 	try:
-		cmd     = subprocess.Popen(cmdarray, stdout=subprocess.PIPE)
+		cmd = subprocess.Popen(cmdarray, stdout=subprocess.PIPE)
 		check['output'] = cmd.communicate()[0].rstrip()
 		check['returncode'] = cmd.returncode
 	except OSError:
 		check['output'] = 'Could not execute "%s"' % cmdline
 		check['returncode'] = 127
+	except ExecTimeoutError:
+		check['output'] = 'Plugin timed out after %s seconds' % timeout
+		check['returncode'] = timeout_returncode
+
+	if timeout:
+		signal.alarm(0)
+		try:
+			cmd.terminate()
+		except OSError:
+			pass
 
 	check['timestamp'] = datetime.datetime.now().strftime('%s')
 	return check
@@ -89,6 +112,18 @@ def exec_check(host_name, service_descr, cmdline):
 def conf2dict(config, opt_host=None, opt_service=None):
 	checks = []
 
+	# Read "plugin_timeout" from "[nagixsc]", default "None" (no timeout)
+	try:
+		timeout = config.getint('nagixsc','plugin_timeout')
+	except (ConfigParser.NoSectionError, ConfigParser.NoOptionError):
+		timeout = None
+
+	# Read "plugin_timeout_returncode" from "[nagixsc]", default "2" (CRITICAL)
+	try:
+		timeout_returncode = config.getint('nagixsc','plugin_timeout_returncode')
+	except (ConfigParser.NoSectionError, ConfigParser.NoOptionError):
+		timeout_returncode = 2
+
 	# Sections are Hosts (not 'nagixsc'), options in sections are Services
 	hosts = config.sections()
 	if 'nagixsc' in hosts:
@@ -113,7 +148,7 @@ def conf2dict(config, opt_host=None, opt_service=None):
 		# Look for host check
 		if '_host_check' in services and not opt_service:
 			cmdline = config.get(host, '_host_check')
-			check = exec_check(host_name, None, cmdline)
+			check = exec_check(host_name, None, cmdline, timeout, timeout_returncode)
 			checks.append(check)
 
 
@@ -129,7 +164,7 @@ def conf2dict(config, opt_host=None, opt_service=None):
 			if service[0] != '_':
 				cmdline = config.get(host, service)
 
-				check = exec_check(host_name, service, cmdline)
+				check = exec_check(host_name, service, cmdline, timeout, timeout_returncode)
 				checks.append(check)
 
 	return checks
diff --git a/sample-configs/conf/timeout.conf b/sample-configs/conf/timeout.conf
new file mode 100644
index 0000000..8d158e0
--- /dev/null
+++ b/sample-configs/conf/timeout.conf
@@ -0,0 +1,19 @@
+[nagixsc]
+# plugin_timeout
+#
+# Timeout of plugin execution in seconds
+# Default: No timeout
+plugin_timeout: 2
+
+# plugin_timeout_returncode
+#
+# Set exit/return code of timed out plugins
+# Default: 2 (CRITICAL)
+plugin_timeout_returncode: 3
+
+[timeout]
+Timeout-1s: /bin/bash -c "sleep 1; echo No or bigger than 1 seconds timeout"
+Timeout-2s: /bin/bash -c "sleep 2; echo No or bigger than 2 seconds timeout"
+Timeout-3s: /bin/bash -c "sleep 3; echo No or bigger than 3 seconds timeout"
+Timeout-4s: /bin/bash -c "sleep 4; echo No or bigger than 4 seconds timeout"
+