OpenTelemetryTesla

Telemetry handler that creates OpenTelemetry spans from Tesla HTTP client events.

It attaches to the following events:

• [:tesla, :request, :start] - emitted at the beginning of the request.
  • Measurement: %{system_time: System.system_time()}
  • Metadata: %{env: Tesla.Env.t()}
• [:tesla, :request, :stop] - emitted at the end of the request.
  • Measurement: %{duration: native_time}
  • Metadata: %{env: Tesla.Env.t()} | %{env: Tesla.Env.t(), error: term()}
• [:tesla, :request, :exception] - emitted when an exception has been raised.
  • Measurement: %{duration: native_time}
  • Metadata: %{kind: Exception.kind(), reason: term(), stacktrace: Exception.stacktrace()}

OpenTelemetry span is enriched with the following attributes that are parsed from Tesla stop event.

• [:method, :opts, :query, :status, :url]
• :headers, it creates one attribute per item in the headers list
• measurement corresponds to the duration of the request

Installation

If available in Hex, the package can be installed by adding opentelemetry_tesla to your list of dependencies in mix.exs:

def deps do
  [
    {:opentelemetry_tesla, "~> 0.1.0-rc.1"}
  ]
end

Setup

In your application start:

def start(_type, _args) do
  OpenTelemetry.register_application_tracer(:my_telemetry_api)
  OpentelemetryTesla.setup()
  children = [
    {Phoenix.PubSub, name: MyApp.PubSub},
    MyAppWeb.Endpoint
  ]
  opts = [strategy: :one_for_one, name: MyApp.Supervisor]
  Supervisor.start_link(children, opts)
end

After this, spans will start to be created whenever a request is completed or if it eventually fails with an exception.