Method open

pymongo/asynchronous/topology.py:218–255

Start monitoring, or restart after a fork. No effect if called multiple times. .. warning:: Topology is shared among multiple threads and is protected by mutual exclusion. Using Topology from a process other than the one that initialized it will emit a warning a

(self)

        self._monitor_tasks: list[MonitorBase] = []

    async def open(self) -> None:
        """Start monitoring, or restart after a fork.

        No effect if called multiple times.

        .. warning:: Topology is shared among multiple threads and is protected
          by mutual exclusion. Using Topology from a process other than the one
          that initialized it will emit a warning and may result in deadlock. To
          prevent this from happening, AsyncMongoClient must be created after any
          forking.

        """
        pid = os.getpid()
        if self._pid is None:
            self._pid = pid
        elif pid != self._pid:
            self._pid = pid
            if sys.version_info[:2] >= (3, 12):
                kwargs = {"skip_file_prefixes": (_pymongo_dir,)}
            else:
                kwargs = {"stacklevel": 6}
            # Ignore B028 warning for missing stacklevel.
            warnings.warn(  # type: ignore[call-overload] # noqa: B028
                "AsyncMongoClient opened before fork. May not be entirely fork-safe, "
                "proceed with caution. See PyMongo's documentation for details: "
                "https://dochub.mongodb.org/core/pymongo-fork-deadlock",
                **kwargs,
            )
            async with self._lock:
                # Close servers and clear the pools.
                for server in self._servers.values():
                    await server.close()
                # Reset the session pool to avoid duplicate sessions in
                # the child process.
                self._session_pool.reset()

        async with self._lock:
            await self._ensure_opened()

    def get_server_selection_timeout(self) -> float:
        # CSOT: use remaining timeout when set.