puppet: Add check_cron_file generic helper.

puppet/zulip/files/nagios_plugins/zulip_app_frontend/check_cron_file

@@ -0,0 +1,52 @@
+#!/usr/bin/env python
+""" Nagios plugin paired with a cron job.  This just verifies that the
+file output by the cron job is correct.
+"""
+from __future__ import print_function
+
+import sys
+import time
+
+# Avoid requiring the typing module to be installed
+if False: from typing import Tuple
+
+def nagios_from_file(results_file):
+    # type: (str) -> Tuple[int, str]
+    """Returns a nagios-appropriate string and return code obtained by
+    parsing the desired file on disk. The file on disk should be of format
+
+    %s|%s % (timestamp, nagios_string)
+
+    This file is created by various nagios checking cron jobs such as
+    check-rabbitmq-queues and check-rabbitmq-consumers"""
+
+    data = open(results_file).read().strip()
+    pieces = data.split('|')
+
+    if not len(pieces) == 4:
+        state = 'UNKNOWN'
+        ret = 3
+        data = "Results file malformed"
+    else:
+        timestamp = int(pieces[0])
+
+        time_diff = time.time() - timestamp
+        if time_diff > 60 * 2:
+            ret = 3
+            state = 'UNKNOWN'
+            data = "Results file is stale"
+        else:
+            ret = int(pieces[1])
+            state = pieces[2]
+            data = pieces[3]
+
+    return (ret, "%s: %s" % (state, data))
+
+if __name__ == "__main__":
+    RESULTS_FILE = sys.argv[1]
+    ret, result = nagios_from_file(RESULTS_FILE)
+
+    print(result)
+    exit(ret)
+
+