Tracking application events in Graphite

I don’t know if that’s a coincidence or not, but drastic changes in application metrics usually happen soon after a product upgrade was made. In fact, whenever I have to deal with new issue on production server, the first thing I do is checking if it was recently updated. No wonder it makes sense to record such events along with other monitoring data.

But assuming our monitoring data is in Graphite, how would we do that?

Continue reading “Tracking application events in Graphite”

Creating collectd data source in JavaScript

Builds graph with data collected by JavaScript app

Exec Plugin

In the variety of collectd plugins there’s one ‘to rule them all’. If due to some course of events all collectd plugins except for Exec would be taken from you, you’d still be able to restore all its functionality with Exec.

As the name suggests, Exec starts external program or script and interprets its output as source of data. To be specific, it looks for lines that follow this scheme:

To be even more specific, these lines would work:

What’s interesting, Exec doesn’t specify in what language script should be written, so anything, including JavaScript, might work. In fact, using JavaScript would be beneficial in some scenarios, e.g. when dealing with RESTful services returning JSON.

Before we try JavaScript app as data source for collectd, let’s talk about PUTVAL lines a little bit more. Continue reading “Creating collectd data source in JavaScript”