pool.py 文件源码

def _wait_for_conn(self, timeout):
        start = time.time()
        remaining = timeout

        while remaining > 0:
            # wait on our condition for the possibility that a connection
            # is useable
            self._await_available_conn(remaining)

            # self.shutdown() may trigger the above Condition
            if self.is_shutdown:
                raise ConnectionException("Pool is shutdown")

            conns = self._connections
            if conns:
                least_busy = min(conns, key=lambda c: c.in_flight)
                with least_busy.lock:
                    if least_busy.in_flight < least_busy.max_request_id:
                        least_busy.in_flight += 1
                        return least_busy, least_busy.get_request_id()

            remaining = timeout - (time.time() - start)

        raise NoConnectionsAvailable()