Hummingbird

A plug to correlate events between services in two lines of Elixir.

Given appropriate trace headers, ships an event for router and response calls.

To Use

defmodule YourAppWeb.YourController do
  use YourAppWeb, :controller

  plug Hummingbird, service_name: "your_service_name"
end

and add the Hummingbird.Telemetry child to your supervision tree:

defmodule YouApp.Application do
  # ..

  def start(_type, _args) do
    children = [
      Hummingbird.Telemetry,
      # ..
    ]

    Supervisor.start_link(children, strategy: :one_for_one, name: YourApp.Supervisor)
  end

  # ..
end

Configuration

Configure OpenCensus

In your config.exs:

# configure opencensus
config :opencensus,
  reporters: [{Opencensus.Honeycomb.Reporter, []}],
  send_interval_ms: 1000

Set the dataset per environment

In your dev, prod, exs files:

# configure write key per dataset/environment
# we use environment variables to protect the secret. It doesn't matter how you
# set the value.  Choose your own adventure.

config :opencensus_honeycomb,
  dataset: "your_dataset_name_goes_here",
  write_key: "${HONEYCOMB_WRITE_KEY}"

Assumptions

Currently, it looks for x-b3-spanid and x-b3-traceid headers on incoming request to create the trace.

Current Example

Thanks

Wraps around https://github.com/open-telemetry/opentelemetry-erlang