# Prometheus.ex
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Elixir [Prometheus.io](https://prometheus.io) client based on [Prometheus.erl](https://github.com/deadtrickster/prometheus.erl).

Starting from v3.0.0 works with Elixir >=1.6 and Erlang >=20. For older verions, please use older tags.

![@skosch dashboard](https://aldusleaf.org/assets/images/2016/09/grafana.jpg)

Dashboard from [Monitoring Elixir apps in 2016: Prometheus and Grafana](https://aldusleaf.org/2016-09-30-monitoring-elixir-apps-in-2016-prometheus-and-grafana.html) by [**@skosch**](https://github.com/skosch).

 - IRC: #elixir-lang on Freenode;
 - [Slack](https://elixir-slackin.herokuapp.com/): #prometheus channel - [Browser](https://elixir-lang.slack.com/messages/prometheus) or App(slack://elixir-lang.slack.com/messages/prometheus).

## Example

```elixir
defmodule ExampleInstrumenter do
  use Prometheus.Metric

  def setup do    
    Histogram.new([name: :http_request_duration_milliseconds,
                   labels: [:method],
                   buckets: [100, 300, 500, 750, 1000],
                   help: "Http Request execution time"])
  end

  def instrument(%{time: time, method: method}) do
    Histogram.observe([name: :http_request_duration_milliseconds, labels: [method]], time)
  end
end
```

or

```elixir
defmodule ExampleInstrumenter do
  use Prometheus.Metric

  @histogram [name: :http_request_duration_milliseconds,
              labels: [:method],
              buckets: [100, 300, 500, 750, 1000],
              help: "Http Request execution time"]

  def instrument(%{time: time, method: method}) do
    Histogram.observe([name: :http_request_duration_milliseconds, labels: [method]], time)
  end
end
```

Here histogram will be declared in auto-generated `@on_load` callback, i.e.
you don't have to call setup manually.

Please read how to [measure durations correctly with prometheus.ex](https://hexdocs.pm/prometheus_ex/time.html#content).

## Integrations / Collectors / Instrumenters
 - [Ecto collector](https://github.com/deadtrickster/prometheus-ecto)
 - [Elli middleware](https://github.com/elli-lib/elli_prometheus)
 - [Extatus - App to report metrics to Prometheus from Elixir GenServers](https://github.com/gmtprime/extatus)
 - [Plugs Instrumenter/Exporter](https://github.com/deadtrickster/prometheus-plugs)
 - [Fuse plugin](https://github.com/jlouis/fuse#fuse_stats_prometheus)
 - [OS process info Collector](https://hex.pm/packages/prometheus_process_collector) (linux-only)
 - [Phoenix instrumenter](https://github.com/deadtrickster/prometheus-phoenix)
 - [RabbitMQ Exporter](https://github.com/deadtrickster/prometheus_rabbitmq_exporter)

## Dashboards

- [Beam Dashboards](https://github.com/deadtrickster/beam-dashboards).

## Installation

[Available in Hex](https://hex.pm/packages/prometheus_ex), the package can be installed as:

1. Add `prometheus_ex` to your list of dependencies in `mix.exs`:

    ```elixir
    def deps do
      [{:prometheus_ex, "~> 3.0"}]
    end
    ```

2. Ensure `prometheus_ex` is started before your application:

    ```elixir
    def application do
      [applications: [:prometheus_ex]]
    end
    ```