Class Pipeline

redis/client.py:1664–2120

Pipelines provide a way to transmit multiple commands to the Redis server in one transmission. This is convenient for batch processing, such as saving all the values in a list to Redis. All commands executed within a pipeline(when running in transactional mode, which is the de

class Pipeline(Redis):
    """
    Pipelines provide a way to transmit multiple commands to the Redis server
    in one transmission.  This is convenient for batch processing, such as
    saving all the values in a list to Redis.

    All commands executed within a pipeline(when running in transactional mode,
    which is the default behavior) are wrapped with MULTI and EXEC
    calls. This guarantees all commands executed in the pipeline will be
    executed atomically.

    Any command raising an exception does *not* halt the execution of
    subsequent commands in the pipeline. Instead, the exception is caught
    and its instance is placed into the response list returned by execute().
    Code iterating over the response list should be able to deal with an
    instance of an exception as a potential value. In general, these will be
    ResponseError exceptions, such as those raised when issuing a command
    on a key of a different datatype.
    """

    UNWATCH_COMMANDS = {"DISCARD", "EXEC", "UNWATCH"}

    def __init__(
        self,
        connection_pool: ConnectionPool,
        response_callbacks,
        transaction,
        shard_hint,
    ):
        self.connection_pool = connection_pool
        self.connection: Optional[Connection] = None
        self.response_callbacks = response_callbacks
        self.transaction = transaction
        self.shard_hint = shard_hint
        self.watching = False
        self.command_stack = []
        self.scripts: Set[Script] = set()
        self.explicit_transaction = False

    def __enter__(self) -> "Pipeline":
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.reset()

    def __del__(self):
        try:
            self.reset()
        except Exception:
            pass

    def __len__(self) -> int:
        return len(self.command_stack)

    def __bool__(self) -> bool:
        """Pipeline instances should always evaluate to True"""
        return True