Yabeda::Puma::Plugin

Built-in metrics for Puma web server monitoring out of the box! Part of the yabeda suite.

Metrics

Works as the Puma plugin and provides following metrics:

• puma_workers - the number of running puma workers
• puma_booted_workers - the number of booted puma workers
• puma_old_workers - the number of old puma worker

Segmented by the worker:

• puma_pool_capacity - the capacity of each worker: the number of requests that the server is capable of taking right now. More details are here.
• puma_running - the number of running threads (spawned threads) for any puma worker
• puma_max_threads - preconfigured maximum number of worker threads
• puma_backlog - the number of backlog threads, the number of connections in that worker's "todo" set waiting for a worker thread.

Installation

Add this line to your application's Gemfile:

gem 'yabeda-puma'

And then execute:

$ bundle

Usage

Add those 2 lines of code to your config/puma.rb file:

activate_control_app
plugin :yabeda

It will activate default puma control application working over the unix socket, and runs the yabeda puma plugin, for registering and collecting the metrics.

Details

In accordance with the architecture of the puma web server lets look how it works:

.

For the configuration above, we will have the list of metrics (with help of yabeda-prometheus exporter):

GET /metrics

puma_backlog{index="0"} 0
puma_backlog{index="1"} 0
puma_running{index="0"} 5
puma_running{index="1"} 5
puma_pool_capacity{index="0"} 1
puma_pool_capacity{index="1"} 5
puma_max_threads{index="0"} 5
puma_max_threads{index="1"} 5
puma_workers 2
puma_booted_workers 2
puma_old_workers 0

See also the grafana screenshot of monitoring puma pool size and it's capacity when application is overloaded:

.

Roadmap (TODO or Help wanted)

• Collect also control-gc puma metrics

Development with Docker

Get local development environment working and tests running is very easy with docker-compose:

docker-compose run app bundle
docker-compose run app bundle exec rspec

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/yabeda-puma.

License

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