Since I had my ESP8266 temperature monitor running I desired to visualize the data over time, in a way that provides: 1) flexible data submission, 2) constrained data growth, 3) flexible visualization in terms of detail. That tool was found in RRDtool, from the developer that wrote MRTG. I had only myself to blame for not understanding how to make it work despite the amount of documentation available.
In my new line of work I came across Prometheus, a more (shall I say) mature form of RRDtool.
What I like about Prometheus
- Easy install on FreeBSD
pkg install prometheusdoes the trick! - Default YAML config works out of the box Already I can see a sample graphs. Very encouraging.
- Available clients for NodeJs/ .NET While I don't depend on .NET much, the NodeJs client is very handy as it handles P99 and higher-grain calculation, agent-side.
- Built-in graphing All I need for a hobby-grade RRD tool is here!
Notes on prom-client: NodeJs client for Prometheus
- Summary data type is useful for collecting quantile-based performance
- collectDefaultMetrics() is useful to monitor process health, but not mandatory