A behaviour for declaring spec.

Any module that wants to exposing metrics or periodic measurements should implement this behaviour.

defmodule MyApp.Cache.TelemetrySpec do
  use CozyTelemetry.Spec

  @impl true
  def metrics(meta) do
    [
      summary("cache.duration",
        unit: {:native, :second},
        tags: [:type, :key]
      ),
      # ...
    ]
  end

  @impl true
  def measurements(meta) do
    [
      {__MODULE__, :dispatch_stats, []},
      # ...
    ]
  end
end

Then, the declared metrics in above module can be loaded with following configuration:

config :my_app, CozyTelemetry,
  meta: [],
  specs: [
    MyApp.Cache.TelemetrySpec
  ],
  # ...