Module: RailsOtelContext::RequestContext

Defined in:
lib/rails_otel_context/request_context.rb

Overview

Thread-local storage for request-scoped context that gets propagated to all spans within a request. Uses raw Thread.current for minimal overhead —no object allocation, no mutex, ~5ns per read/write.

Lifecycle:

1. Railtie's around_action sets controller + action at request start
2. CallContextProcessor reads them on every child span's on_start
3. around_action's ensure block clears them when the request ends

Thread safety: each Puma thread has its own slot — no sharing, no contention.

Constant Summary collapse

CONTROLLER_KEY = 
:_rails_otel_ctx_controller
ACTION_KEY = 
:_rails_otel_ctx_action
QUERY_COUNT_KEY = 
:_rails_otel_ctx_qcount

Class Method Summary collapse

Class Method Details

.action ⇒ Object 



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# File 'lib/rails_otel_context/request_context.rb', line 36

def action
  Thread.current[ACTION_KEY]
end

.clear! ⇒ Object 



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# File 'lib/rails_otel_context/request_context.rb', line 40

def clear!
  Thread.current[CONTROLLER_KEY]  = nil
  Thread.current[ACTION_KEY]      = nil
  Thread.current[QUERY_COUNT_KEY] = nil
end

.controller ⇒ Object 



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# File 'lib/rails_otel_context/request_context.rb', line 32

def controller
  Thread.current[CONTROLLER_KEY]
end

.fetch ⇒ Object

Returns [controller, action] in a single Thread.current access.



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# File 'lib/rails_otel_context/request_context.rb', line 27

def fetch
  t = Thread.current
  [t[CONTROLLER_KEY], t[ACTION_KEY]]
end

.set(controller:, action:) ⇒ Object 



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# File 'lib/rails_otel_context/request_context.rb', line 20

def set(controller:, action:)
  Thread.current[CONTROLLER_KEY]  = controller
  Thread.current[ACTION_KEY]      = action
  Thread.current[QUERY_COUNT_KEY] = nil
end