Helpers are libraries available to all formatters that can be used to supplement the content they generate. For example, a helper can pull in external information (such as a graph) that is relevant to a service that Nagios is alerting on.
nagios-herald comes with the following helpers as examples:
- GangliaGraph - Downloads relevant graphs to be embedded in (email) messages.
- SplunkReporter - Queries Splunk for information to add to an alert.
- LogstashQuery - Queries logstash with either a kibaba-style query or a file containing query JSON
- UrlImage - Generic helper to download images.
Helpers are located in lib/nagios-herald/helpers/.
You may write your own helpers and use them with nagios-herald. These helper classes can live in any location. A custom helper should subclass Helper::Base.
To use a custom helper, you must add the --helper-dir flag to any notification command stanzas in commands.cfg that will use that helper class. helper-dir specifies the directory in which your custom helper class is stored. You can also define the location of custom helper classes in the config.yml configuration file.
# notify by carrier pigeon
define command {
command_name notify-host-by-pigeon
command_line /usr/local/nagios-herald/bin/nagios-herald --message-dir=/usr/local/nagios-herald-messages/ --message-type=pigeon --formatter=$_HOSTMESSAGE_FORMATTER_NAME$ -- nagios-cgi-url=http://nagios.example.com/nagios/cgi-bin/cmd.cgi [email protected] --helper-dir=/usr/local/nagios-herald-helpers/
}
define command {
command_name notify-service-by-pigeon
command_line /usr/local/nagios-herald/bin/nagios-herald --message-dir=/usr/local/nagios-herald-messages/ --message-type=pigeon -- formatter=$_SERVICEMESSAGE_FORMATTER_NAME$ --nagios-cgi-url=http://nagios.example.com/nagios/cgi-bin/cmd.cgi [email protected] --helper-dir=/usr/local/nagios-herald-helpers/
}