Request Tracer

Request Tracer is a Ruby gem that helps tracing requests through a chain of services. It is based on ZipkinTracer but doesn't force you to use Zipkin.

One possible use case is to use your logger to log traces and spans and reuse your existing log aggregation tool of choice (e.g. ELK) to get all logs across all services that were involved in a client's service call.

How it works

Request Tracer integrates with various other gems in order to transparently read incoming trace headers and add trace headers to outgoing service calls. A good introduction into Zipkin terminology can be found here.

Spawning traces

If you want to spawn from an existing trace or create a fresh one if there is no current trace, you can use

RequestTracer::Trace.record do
  # Some code that might contain outgoing calls etc
end

Reading trace headers

In your config.ru add the RackHandler middleware like this:

require 'request_tracer'
require 'request_tracer/integration/rack_handler'

use RequestTracer::Integration::RackHandler
run MyApp.new

Writing trace headers

RestClient

# Somewhere in an initializer (e.g. under `config/initializers/request-tracing.rb`)
RequestTracer.integrate_with(:rest_client)

# Perform rest calls as usual
RestClient.get("http://www.example.com")

Faraday

# Somewhere in an initializer (e.g. under `config/initializers/request-tracing.rb`)
RequestTracer.integrate_with(:faraday)

# Client instantiation
client = Faraday.new("http://www.example.com/") do |conn|
  conn.use :tracing
  conn.adapter Faraday.default_adapter
end

# Perform rest calls as usual
client.get