Multigraph plugin to monitor nginx cache status (everything, not only hits, misses and expired objects)

plugins/nginx/nginx-cache-multi_

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+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# vim: set fileencoding=utf-8
+#
+# Munin plugin to monitor nginx cache statuses.
+#
+# Copyright Igor Borodikhin
+#
+# License : GPLv3
+#
+# This plugin generates two graphs - with number of requests and with percents.
+# Create these symlinks:
+#    ln -s /usr/share/munin/plugins/nginx-cache-multi_ /etc/munin/plugins/nginx-cache-multi_number
+#    ls -s /usr/share/munin/plugins/nginx-cache-multi_ /etc/munin/plugins/nginx-cache-multi_percent
+#
+# You can override the log file location.
+#
+#   [nginx-cache-multi]
+#       env.logfile /var/log/nginx/cache-access.log
+#
+# Nginx must be configured to include "cs=$upstream_cache_status" in the
+# log file. Example format:
+#
+# log_format cache '$remote_addr - $host [$time_local] "$request" $status '
+#                  '$body_bytes_sent "$http_referer" '
+#                  'rt=$request_time ut="$upstream_response_time" '
+#                  'cs=$upstream_cache_status';
+#%# capabilities=autoconf
+#%# family=contrib
+
+import os, sys, re
+
+# How we've been called
+prog_name = sys.argv[0]
+prog_name = prog_name[prog_name.rfind("/")+1:]
+
+# What is graph type?
+graph_type = prog_name[prog_name.rfind("_")+1:]
+
+# Where to store plugin state
+if "MUNIN_PLUGSTATE" in os.environ:
+    state_dir = os.environ["MUNIN_PLUGSTATE"]
+else:
+    state_dir = None
+
+# Log path
+if "logfile" in os.environ:
+    log_file = os.environ["logfile"]
+else:
+    log_file = "/var/log/nginx/access.log"
+
+cache_status_list = { "MISS" : 0, "EXPIRED" : 0, "UPDATING" : 0, "STALE" : 0, "HIT" : 0, "NONE" : 0, "TOTAL" : 0 }
+
+if len(sys.argv) == 2 and sys.argv[1] == "autoconf":
+    print "yes"
+elif len(sys.argv) == 2 and sys.argv[1] == "config":
+    if graph_type == "number":
+        vlabel = "requests"
+    else:
+        vlabel = "%"
+
+    # Parent graph declaration
+    print "multigraph nginx_cache_multi_%s" % graph_type
+    print "graph_title Nginx cache status (%s)" % graph_type
+    print "graph_category nginx"
+    print "graph_vlabel %s" % vlabel
+    for key in cache_status_list.keys():
+        if key != "TOTAL":
+            print "%s.label %s" % (key.lower(), key.capitalize())
+            print "%s.draw AREASTACK" % key.lower()
+            print "%s.min 0" % key.lower()
+    print ""
+
+    for key in cache_status_list.keys():
+        # Other graphs declaration
+        if key != "TOTAL":
+            print "multigraph nginx_cache_multi_%s.%s" % (graph_type, key.lower())
+            print "graph_title Nginx cache status (%s) - %s" % (graph_type, key.capitalize())
+            print "graph_category nginx"
+            print "graph_vlabel %s" % vlabel
+            print "total.label Total"
+            print "total.draw AREA"
+            print "total.min 0"
+            print "total.colour ff0000"
+            print "%s.label %s" % (key.lower(), key.capitalize())
+            print "%s.draw AREA" % key.lower()
+            print "%s.min 0" % key.lower()
+            print "%s.colour 0000ff" % key.lower()
+            print ""
+else:
+    last_byte_file = "%s/%s_state" % (state_dir, prog_name)
+    last_byte_handle = None
+
+    # Load last position in log file
+    try:
+        last_byte_handle = open(last_byte_file, "r")
+        last_byte = int(last_byte_handle.read())
+    except Exception:
+        last_byte = 0
+
+    if last_byte_handle != None:
+        last_byte_handle.close()
+
+    # Open log file for reading
+    try:
+        log_handle = open(log_file, "r")
+    except Exception:
+        print "Log file %s not readable" % log_file
+        sys.exit(1)
+
+    # Find out log size and set proper position depending on log size
+    try:
+        log_size = int(os.path.getsize(log_file))
+    except ValueError:
+        log_size = 0
+
+    if log_size < last_byte:
+        last_byte = 0
+
+    # Set position on file
+    log_handle.seek(last_byte)
+
+    reg_exp = re.compile(r"cs=([^\s]+)")
+
+    for line in log_handle:
+        match = reg_exp.search(line)
+        cache_status = match.group(1)
+        if cache_status == "-":
+            cache_status = "NONE"
+        cache_status_list[cache_status] += 1
+        cache_status_list["TOTAL"] += 1
+
+    try:
+        last_byte_handle = open(last_byte_file, "w")
+        last_byte_handle.write(str(log_handle.tell()))
+        last_byte_handle.close()
+    except Exception:
+        sys.exit(1)
+
+    log_handle.close()
+
+    # Handle graph type (_num for absolute numbers and anything alse for percents)
+    if graph_type != "number":
+        for key in cache_status_list.keys():
+            if key != "TOTAL":
+                cache_status_list[key] = cache_status_list[key] * 100 / cache_status_list["TOTAL"]
+        cache_status_list["TOTAL"] = 100
+
+
+    # Parent graph declaration
+    print "multigraph nginx_cache_multi_%s" % graph_type
+    #print "total.value %s" % cache_status_list["TOTAL"]
+    for key in cache_status_list.keys():
+        if key != "TOTAL":
+            print "%s.value %s" % (key.lower(), cache_status_list[key])
+    print ""
+
+    for key in cache_status_list.keys():
+        # Other graphs declaration
+        if key != "TOTAL":
+            print "multigraph nginx_cache_multi_%s.%s" % (graph_type, key.lower())
+            print "total.value %s" % cache_status_list["TOTAL"]
+            print "%s.value %s" % (key.lower(), cache_status_list[key])
+            print ""