simple-prometheus-exporter
A trivial Prometheus exporter library and helper macro for generating Prometheus-compatible metric endpoints. You should use the regular rust-prometheus crate for serious production use.
Use cases
This library is well suited for converting other APIs or sensors to the Prometheus metric format, particularly where fields exposed by the external source vary over time. It's often better to have gaps in the time series than to back-fill the last value, however traditional exporter libraries make this difficult.
Instead, this library helps applications generate the metrics response from scratch, making it easy to conditionally format the response based on whatever metrics are actually available and accurate at a particular instant.
Examples
These projects make use of this exporter library:
- https://github.com/timothyb89/co2-exporter - an exporter for USB CO2 sensors
- https://github.com/timothyb89/openweathermap-exporter - an exporter for OpenWeatherMap
Limitations and notes
- This library only formats metrics; mapping this to an HTTP endpoint is left as an exercise to the reader.
- This library is compatible with Prometheus's exposition format but does not enforce its rules. Users are responsible for using a "supported metric primitive", at least to the extent they're more than key/value pairs.
- No prometheus metric or label descriptions are written. The
HELPandTYPEfields aren't actually required (or to my knowledge, used at all, except by human readers) and are not supported. - Users are responsible for following (or not following) the metric naming conventions
- It's not particularly efficient and probably clones strings too much