Live Requests — Ruby

Works with any Rack application — Rails, Sinatra, Roda and friends. Request spans are published by Rack middleware running inside your server process, so there is nothing to add to your controllers.

Record your server

Start the server under CodeTracer instead of directly:

ct record --server --lang ruby -o ./trace -- rails server --port 3000

or, for a Sinatra app:

ct record --server --lang ruby -o ./trace -- ruby app.rb -p 4567

Flags after the program name are passed through unchanged. The command stays in the foreground; stop it with Ctrl-C, which is a normal end.

Watch requests arrive

In a second terminal, with the server still running:

ct replay -t ./trace

Send some traffic and the **Requests** panel fills in:

curl http://localhost:3000/users/7

Double-click a row to land in the action that handled it. Because the whole server is one recording, you can step backwards out of your controller into the Rack middleware stack that ran first — including middleware you did not write.

Open a recording later

ct replay ./trace

What gets recorded

• **Route patterns**, so /users/7 and /users/9 group under the same

endpoint.

• **Status and duration** per request.
• **Errors**, including the exception message for requests that raised.

Requirements

Ruby 3.0 or newer.