Module: RobotLab::Web::EventSink

Defined in:
lib/robot_lab/web/event_sink.rb

Overview

The bridge between robot_lab's synchronous hook dispatch and a consumer (an SSE stream, a collecting array, anything responding to #call).

robot_lab hooks are class-level singletons, so there is no instance on which to hang a per-connection callback. We instead stash the consumer in a thread-local for the duration of a run. Because Robot#run dispatches its hooks synchronously on the calling thread, the StreamHook sees the right sink. (Caveat: a robot that executes tools on other threads/Ractors would not propagate this — fine for the core synchronous path.)

In effect this gives a robot run an on_event: callback without changing robot_lab's API.

Constant Summary collapse

KEY = 
:robot_lab_web_event_sink

Class Method Summary collapse

Class Method Details

.capture(sink) ⇒ Object

Run the block with sink (any callable taking an Event) installed as the current consumer. Restores the previous sink afterward.



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# File 'lib/robot_lab/web/event_sink.rb', line 24

def capture(sink)
  previous = Thread.current[KEY]
  Thread.current[KEY] = sink
  yield
ensure
  Thread.current[KEY] = previous
end

.current ⇒ Object 



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# File 'lib/robot_lab/web/event_sink.rb', line 32

def current
  Thread.current[KEY]
end

.emit(event) ⇒ Object

Deliver an Event to the current sink (if any). Never raises into the run — a broken consumer must not break the robot.



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# File 'lib/robot_lab/web/event_sink.rb', line 38

def emit(event)
  sink = current
  sink&.call(event)
rescue StandardError
  nil
end