Add munin_status shell script to monitor log file

Monitor log file on munin-master based on errors and more.

munin_status

@@ -0,0 +1,128 @@
+#!/bin/sh
+# -*- sh -*-
+: <<=cut
+
+=head1 NAME
+
+munin_status - Plugin to monitor munin updates
+
+=head1 APPLICABLE SYSTEMS
+
+All systems with "sh", "pygtail", "awk" and "munin"
+
+=head1 CONFIGURATION
+
+The following is the default configuration
+
+  [munin_status]
+  user munin
+  env.muninupdate /var/log/munin/munin-update.log
+  env.pygtail /opt/local/bin/pygtail
+
+You could trigger alerts on update failures
+
+  [munin_status]
+  env.munin_fatal_critical 0
+  env.munin_error_critical 0
+  env.munin_warning_warning 0
+  env.munin_warning_critical 5
+
+=head1 INTERPRETATION
+
+This plugin shows a graph with one line per munin state:
+INFO, WARNING, ERROR, FATAL.
+
+=head1 MAGIC MARKERS
+
+  #%# family=auto
+  #%# capabilities=autoconf
+
+=head1 VERSION
+
+  0.1
+
+=head1 AUTHOR
+
+Thomas Merkel <tm@core.io>
+
+=head1 LICENSE
+
+GPLv2
+
+=cut
+
+
+##############################
+# Includes
+
+# shellcheck disable=SC1091
+. "$MUNIN_LIBDIR/plugins/plugin.sh"
+
+##############################
+# Configurable variables
+muninupdate=${muninupdate:-/var/log/munin/munin-update.log}
+pygtail_bin=${pygtail_bin:-/opt/local/bin/pygtail}
+
+##############################
+# Functions
+
+# Print the munin values
+values() {
+    # Set offset
+    "$pygtail_bin" "$muninupdate" | awk '
+        BEGIN { split("INFO WARNING ERROR FATAL", a); for (i = 1; a[i]; ++i) A[i] = 0 }
+        { for (i = 1; a[i]; ++i) if (match($0, a[i])) ++A[i] }
+        END { for (i = 1; a[i]; ++i) print "munin_"tolower(a[i])".value " A[i]}
+    '
+    chmod 640 "${muninupdate}.offset"
+}
+
+# Print the munin config
+config() {
+    echo 'graph_title Munin update status groupped by log levels'
+    echo 'graph_info This graph shows INFO, WARNING, ERROR and FATAL status'
+    echo 'graph_category munin'
+    echo 'graph_vlabel Number of status'
+
+    echo 'graph_args --base 1000 -l 0'
+    echo 'graph_total total'
+    echo 'graph_printf %6.0lf'
+
+    echo 'munin_info.label INFO'
+    print_warning munin_info
+    print_critical munin_info
+    echo 'munin_warning.label WARNING'
+    print_warning munin_warning
+    print_critical munin_warning
+    echo 'munin_error.label ERROR'
+    print_warning munin_error
+    print_critical munin_error
+    echo 'munin_fatal.label FATAL'
+    print_warning munin_fatal
+    print_critical munin_fatal
+}
+
+# Print autoconfiguration hint
+autoconf() {
+    if [ -r "${muninupdate}" ] && [ -x "$pygtail_bin" ]; then
+        echo "yes"
+    else
+        echo "missing (${muninupdate} or (${pygtail_bin})"
+    fi
+    exit
+}
+
+##############################
+# Main
+
+case "$1" in
+    config)
+        config
+        ;;
+    autoconf)
+        autoconf
+        ;;
+    *)
+        values
+        ;;
+esac