Method: Que::ConnectionPool#checkout

Defined in:
lib/que/connection_pool.rb

#checkout ⇒ Object 



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# File 'lib/que/connection_pool.rb', line 15

def checkout
  # Do some asserting to ensure that the connection pool we're using is
  # behaving properly.
  @connection_proc.call do |conn|
    # Did this pool already have a connection for this thread?
    preexisting = wrapped = current_connection

    begin
      if preexisting
        # If so, check that the connection we just got is the one we expect.
        if preexisting.wrapped_connection.backend_pid != conn.backend_pid
          raise Error, "Connection pool is not reentrant! previous: #{preexisting.wrapped_connection.inspect} now: #{conn.inspect}"
        end
      else
        # If not, make sure that it wasn't promised to any other threads.
        sync do
          Que.assert(@checked_out.add?(conn.backend_pid)) do
            "Connection pool didn't synchronize access properly! (entrance: #{conn.backend_pid})"
          end
        end

        self.current_connection = wrapped = Connection.wrap(conn)
      end

      yield(wrapped)
    ensure
      if preexisting.nil?
        # We're at the top level (about to return this connection to the
        # pool we got it from), so mark it as no longer ours.
        self.current_connection = nil

        sync do
          Que.assert(@checked_out.delete?(conn.backend_pid)) do
            "Connection pool didn't synchronize access properly! (exit: #{conn.backend_pid})"
          end
        end
      end
    end
  end
end