OpentelemetryFinch

OpentelemetryFinch uses telemetry handlers to create OpenTelemetry spans from Finch events.

Installation

The package can be installed by adding opentelemetry_finch to your list of dependencies in mix.exs:

  def deps do
    [
      {:opentelemetry_finch, "~> 0.1"}
    ]
  end

In your application start:

  def start(_type, _args) do
    OpentelemetryFinch.setup()

    # ...
  end

Since this instrumentation is based on telemetry, it is not possible to automatically propagate the context in the http headers. If you need to perform context propagation, you should opt for manual instrumentation. Something like this:

    require OpenTelemetry.Tracer, as: Tracer

    Tracer.with_span "HTTP #{url}" do
      headers = :otel_propagator_text_map.inject([])

      with request <- Finch.build(:get, url, headers),
           {:ok, response} <- Finch.request(request, HttpFinch) do

        Tracer.set_attributes([
          {"http.url", url},
          {"http.method", request.method},
          {"http.status_code", response.status}])
        {:ok, response}
      else
        {:error, %{__exception__: true} = error} ->
          Tracer.set_status(:error, Exception.message(error))
          {:error, error}
      end
    end

Compatibility Matrix

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/opentelemetry_finch.