Method _select_server

pymongo/synchronous/mongo_client.py:1818–1863

Select a server to run an operation on this client. :Parameters: - `server_selector`: The server selector to use if the session is not pinned and no address is given. - `session`: The ClientSession for the next operation, or None. May be pinned to

(
        self,
        server_selector: Callable[[Selection], Selection],
        session: Optional[ClientSession],
        operation: str,
        address: Optional[_Address] = None,
        deprioritized_servers: Optional[list[Server]] = None,
        operation_id: Optional[int] = None,
    )

                yield conn

    def _select_server(
        self,
        server_selector: Callable[[Selection], Selection],
        session: Optional[ClientSession],
        operation: str,
        address: Optional[_Address] = None,
        deprioritized_servers: Optional[list[Server]] = None,
        operation_id: Optional[int] = None,
    ) -> Server:
        """Select a server to run an operation on this client.

        :Parameters:
          - `server_selector`: The server selector to use if the session is
            not pinned and no address is given.
          - `session`: The ClientSession for the next operation, or None. May
            be pinned to a mongos server address.
          - `address` (optional): Address when sending a message
            to a specific server, used for getMore.
        """
        try:
            topology = self._get_topology()
            if session and not session.in_transaction:
                session._transaction.reset()
            if not address and session:
                address = session._pinned_address
            if address:
                # We're running a getMore or this session is pinned to a mongos.
                server = topology.select_server_by_address(
                    address, operation, operation_id=operation_id
                )
                if not server:
                    raise AutoReconnect("server %s:%s no longer available" % address)  # noqa: UP031
            else:
                server = topology.select_server(
                    server_selector,
                    operation,
                    deprioritized_servers=deprioritized_servers,
                    operation_id=operation_id,
                )
            return server
        except PyMongoError as exc:
            # Server selection errors in a transaction are transient.
            if session and session.in_transaction:
                exc._add_error_label("TransientTransactionError")
                session._unpin()
            raise

    def _conn_for_writes(
        self, session: Optional[ClientSession], operation: str