Merge lp:~brad-marshall/charms/precise/nrpe-external-master/add-systemd-nagios-check into lp:charms/nrpe-external-master

[Brad Marshall]

Add systemd nagios check

[Review Queue (review-queue)]

The results (PASS) are in and available here: http://juju-ci.vapour.ws:8080/job/charm-bundle-test-lxc/4101/

review: Approve (automated testing)

[Review Queue (review-queue)]

The results (PASS) are in and available here: http://juju-ci.vapour.ws:8080/job/charm-bundle-test-aws/4115/

review: Approve (automated testing)

[Stuart Bishop (stub)]

review: Approve

[Stuart Bishop (stub)]

Looks good.

The new file does nothing until the charm adds a check that makes use of it.

=== added file 'files/check_systemd.py'
--- files/check_systemd.py	1970-01-01 00:00:00 +0000
+++ files/check_systemd.py	2016-05-09 05:00:31 +0000
@@ -0,0 +1,39 @@
+#!/usr/bin/python3
+#
+# Copyright 2016 Canonical Ltd
+#
+# Author: Brad Marshall <[e-mail]>
+#
+# Based on check_upstart_job and https://zignar.net/2014/09/08/getting-started-with-dbus-python-systemd/
+#
+
+import dbus, sys
+
+service_arg = sys.argv[1]
+service_name = "%s.service" % service_arg
+
+try:
+    bus = dbus.SystemBus()
+    systemd = bus.get_object('org.freedesktop.systemd1', '/org/freedesktop/systemd1')
+    manager = dbus.Interface(systemd, dbus_interface='org.freedesktop.systemd1.Manager')
+    try:
+        service_unit = manager.LoadUnit(service_name)
+        service_proxy = bus.get_object('org.freedesktop.systemd1', str(service_unit))
+        service = dbus.Interface(service_proxy, dbus_interface='org.freedesktop.systemd1.Unit')
+        service_res = service_proxy.Get('org.freedesktop.systemd1.Unit','ActiveState', dbus_interface='org.freedesktop.DBus.Properties')
+
+        if service_res == 'active':
+            print('OK: %s is running' % service_name)
+            sys.exit(0)
+        else:
+            print('CRITICAL: %s is not running' % service_name)
+            sys.exit(2)
+
+    except dbus.DBusException as e:
+        print('CRITICAL: unable to find %s in systemd' % service_name)
+        sys.exit(2)
+
+except dbus.DBusException as e:
+    print('CRITICAL: unable to connect to system for %s' % service_name)
+    sys.exit(2)
+