Evil::Metrics::Prometheus

Adapter for easy exporting your collected evil metrics from your application to the Prometheus!

One more? Why not X?

https://github.com/discourse/prometheus_exporter – built on assumption that various processes (web, jobs, etc) are able to communicate between them on single machine. But in containerized environments all your processes on different “machines”!
https://github.com/getqujing/prome – actually inspired this all these gems but seems abandoned and lacks extensibility.

Installation

Add this line to your application's Gemfile:

gem 'evil-metrics'
# Then add monitoring system adapter, e.g.:
# gem 'evil-metrics-prometheus'

And then execute:

$ bundle

Usage

Exporting from running web servers:

Place following in your config.ru before running your application:
```
use Evil::Metrics::Prometheus::Exporter
```
Metrics will be available on /metrics path.
Run web-server from long-running processes (delayed jobs, …):
```
Evil::Metrics::Prometheus::Exporter.start_metrics_server!
```
WEBrick will be launched in separate thread and will serve metrics on /metrics path.

See evil-metrics-sidekiq for example.

Listening address is configured via PROMETHEUS_EXPORTER_BIND env variable (default is 0.0.0.0).

Port is configured by PROMETHEUS_EXPORTER_PORT or PORT variables (default is 9310).
Use push gateway for short living things (rake tasks, cron jobs, …):
```
Evil::Metrics::Prometheus.push_gateway.add(Evil::Metrics::Prometheus.registry)
```
Address of push gateway is configured with PROMETHEUS_PUSH_GATEWAY env variable.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/evil-metrics/evil-metrics-prometheus.

License

The gem is available as open source under the terms of the MIT License.