OpenTelemetry.Tesla

opentelemetry_tesla provides an OpenTelemetry integration for the Tesla HTTP client library.

Installation

Add opentelemetry, opentelemetry_api, and opentelemetry_tesla to your deps in
mix.exs:

{:opentelemetry, "~> 0.6.0"},
{:opentelemetry_api, "~> 0.6.0"},
{:opentelemetry_tesla, "~> 0.6.0-rc.1"},

In your Tesla client module, plug the telemetry middleware last. If the client is for a
particular peer service, name it wit the peer_service option. For example:

defmodule MyApp.MyPeer.Client do
  use Tesla

  plug Tesla.Middleware.Headers, [{"user-agent", inspect(__MODULE__)}]
  plug Tesla.Middleware.Compression, format: "gzip"
  plug OpenTelemetry.Tesla.Middleware, peer_service: "my_peer"
end

If the client is for a peer service you trust with your propagation headers, set the propagator:

defmodule MyApp.MyPeer.Client do
  use Tesla

  plug Tesla.Middleware.Headers, [{"user-agent", inspect(__MODULE__)}]
  plug Tesla.Middleware.Compression, format: "gzip"
  plug OpenTelemetry.Tesla.Middleware,
    peer_service: "my_peer",
    propagator: :otel_propagator_http_w3c
end

Disable propagation implicitly by leaving propagator unset, or explicitly by setting it to
nil or false. You can also use the default W3C propagator by setting it to true.

Trace Span Attributes

OpenTelemetry.Tesla sends the following trace span attributes, following the OpenTelemetry Trace
Semantic Conventions:

In the table above headings, method, status, and url are members of
t:Tesla.Env.t/0. We parse url with URI.parse/1 and reassemble it with URI.to_string/1.