How to populate InfluxDB metrics using handlers

What are Sensu handlers?

Sensu event handlers are actions executed by the Sensu server on events. In this example, we’ll use a handler to populate a time series database. If you’re not totally comfortable with handlers yet, check out the in-depth guide on handlers first!

Using a handler to populate InfluxDB

The purpose of this guide is to help you populate Sensu metrics into the time series database InfluxDB. Metrics can be collected from check output or from the Sensu StatsD Server.

Installing the handler command

The first thing you’ll want to do is create an executable script named sensu-influxdb-handler, which will be responsible for populating a configurable InfluxDB with Sensu metrics. The source code and installation instructions of this script is available on GitHub. You can also download the binaries directly from releases.

Creating the handler

Now that our handler command is installed, the second step is to create a handler that we will call influx-db, which is a pipe handler that pipes event data into our previous script named sensu-influxdb-handler. We will also pass the database name, address, username, and password of the InfluxDB you wish to populate. We’ll use environment variables (env-vars) to pass the InfluxDB address, username, and password to the handler.

sensuctl handler create influx-db \
--type pipe \
--command "sensu-influxdb-handler -d sensu" \
--env-vars "INFLUXDB_ADDR=http://influxdb.default.svc.cluster.local:8086, INFLUXDB_USER=sensu, INFLUXDB_PASS=password"

Assigning the handler to an event

With the influx-db handler now created, it can be assigned to a check for check output metric extraction. In this example, the check name is collect-metrics:

sensuctl check set-output-metric-handlers collect-metrics influx-db

The handler can also be assigned to the Sensu StatsD listener at agent startup to pass all StatsD metrics into InfluxDB:

sensu-agent start --statsd-event-handlers influx-db

Validating the handler

It might take a few moments once the handler is assigned to the check or StatsD server, for Sensu to receive the metrics, but once an event is handled, you should start to see your InfluxDB being populated! Otherwise, you can verify the proper behavior of this handler by using sensu-backend logs. See the troubleshooting guide for log locations by platform.

Whenever an event is being handled, a log entry is added with the message "handler":"influx-db","level":"debug","msg":"sending event to handler", followed by a second one with the message "msg":"pipelined executed event pipe handler","output":"","status":0.

Next steps

You now know how to apply a handler to metrics and take action on events. From this point, here are some recommended resources: