Module: MCP::Instrumentation

Included in:
Server
Defined in:
lib/mcp/instrumentation.rb

Instance Method Summary collapse

Instance Method Details

#add_instrumentation_data(**kwargs) ⇒ Object 



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# File 'lib/mcp/instrumentation.rb', line 43

def add_instrumentation_data(**kwargs)
  @instrumentation_data.merge!(kwargs)
end

#instrument_call(method, server_context: {}, exception_already_reported: nil, &block) ⇒ Object 



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# File 'lib/mcp/instrumentation.rb', line 5

def instrument_call(method, server_context: {}, exception_already_reported: nil, &block)
  start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  begin
    @instrumentation_data = {}
    add_instrumentation_data(method: method)

    result = configuration.around_request.call(@instrumentation_data, &block)

    result
  rescue => e
    already_reported = begin
      !!exception_already_reported&.call(e)
    # rubocop:disable Lint/RescueException
    rescue Exception
      # rubocop:enable Lint/RescueException
      # The predicate is expected to be side-effect-free and return a boolean.
      # Any exception raised from it (including non-StandardError such as SystemExit)
      # must not shadow the original exception.
      false
    end

    unless already_reported
      add_instrumentation_data(error: :internal_error) unless @instrumentation_data.key?(:error)
      configuration.exception_reporter.call(e, server_context)
    end

    raise
  ensure
    end_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
    add_instrumentation_data(duration: end_time - start_time)

    # Backward compatibility: `instrumentation_callback` is soft-deprecated
    # in favor of `around_request`, but existing callers still expect it
    # to fire after every request until it is removed in a future version.
    configuration.instrumentation_callback.call(@instrumentation_data)
  end
end