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Gem Version

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

Sponsored by Evil Martians

One more? Why not X?


Add this line to your application's Gemfile:

gem 'yabeda-prometheus'

And then execute:

$ bundle


  1. Exporting from running web servers:

    Place following in your before running your application:

    use Yabeda::Prometheus::Exporter

    Metrics will be available on /metrics path (configured by :path option).

    Also you can mount it in Rails application routes as standalone Rack application.

  2. Run web-server from long-running processes (delayed jobs, …):


    WEBrick will be launched in separate thread and will serve metrics on /metrics path.

    See yabeda-sidekiq for example.

    Listening address is configured via PROMETHEUS_EXPORTER_BIND env variable (default is

    Port is configured by PROMETHEUS_EXPORTER_PORT or PORT variables (default is 9394).

  3. Use push gateway for short living things (rake tasks, cron jobs, …):


    Address of push gateway is configured with PROMETHEUS_PUSH_GATEWAY env variable.

Multi-process server support

To use Unicorn or Puma in clustered mode, you'll want to set up underlying prometheus-client gem to use DirectFileStore, which aggregates metrics across the processes.

Prometheus::Client.config.data_store = '/tmp/prometheus_direct_file_store')

See more information at prometheus-client README.

Aggregation settings

You can specify aggregation policy in gauges declaration:

group :some do
  gauge :tasks do
    comment "Number of test tasks"
    aggregation :max


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


Bug reports and pull requests are welcome on GitHub at


  1. Bump version number in lib/yabeda/prometheus/version.rb

    In case of pre-releases keep in mind rubygems/rubygems#3086 and check version with command like

  2. Fill with missing changes, add header with version and date.

  3. Make a commit:

    git add lib/yabeda/prometheus/version.rb
    version=$(ruby -r ./lib/yabeda/prometheus/version.rb -e "puts")
    git commit --message="${version}: " --edit
  4. Create annotated tag:

    git tag v${version} --annotate --message="${version}: " --edit --sign
  5. Fill version name into subject line and (optionally) some description (list of changes will be taken from changelog and appended automatically)

  6. Push it:

    git push --follow-tags
  7. GitHub Actions will create a new release, build and push gem into RubyGems! You're done!


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