# AbsintheMetrics
[](https://travis-ci.org/soundtrackyourbrand/absinthe-metrics)
AbsintheMetrics provides time (or counter) based metrics for your [Absinthe](https://github.com/absinthe-graphql/absinthe) resolvers to allow you to keep track of where your queries are spending their time.
Usage is fairly straight forward,
```elixir
defmodule MyApp.Instrumenter do
use AbsintheMetrics,
backend: AbsintheMetrics.Backend.PrometheusHistogram,
# See prometheus.ex for more examples
arguments: [buckets: {:exponential, 250, 1.5, 7}]
end
defmodule MyApp.Schema do
use Absinthe.Schema
def middleware(middlewares, field, object) do
MyApp.Instrumenter.instrument(middlewares, field, object)
end
end
# in application.ex
defmodule MyApp do
def start(_type, _args) do
# initialize all available metrics in your schema
MyApp.Instrumenter.install(MyApp.Schema)
# ...
end
end
```
How metrics are gathered depends on the backend, but for `PrometheusHistogram` the format is `#{object}_#{field}_duration_microseconds` or `query_field_duration_microseconds` for root queries.
### Adding backends
Adding additional backends is pretty straight forward, you just need to implement the `AbsintheMetrics` behaviour,
```elixir
defmodule LogBackend do
@behaviour AbsintheMetrics
require Logger
# Called during application start to allow you to register
# fields with your TSDB
def field(object, field, _args \\ []) do
Logger.info("install field #{object}_#{field}")
end
# Called every time a value is observed
# status can be :ok or :error
def instrument(object, field, {status, _result}, time) do
metric = "#{object}_#{field}"
case status do
:error -> Logger.warn("#{metric} failed (took: #{inspect time})")
:ok -> Logger.info("#{metric} took: #{inspect time}")
end
end
end
```
## Installation
If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `absinthe_metrics` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:absinthe_metrics, "~> 0.1.0"}
]
end
```
Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
be found at [https://hexdocs.pm/absinthe_metrics](https://hexdocs.pm/absinthe_metrics).
