redis/redis-py · error · RedisClusterException

method load_scripts() is not implemented

Error message

method load_scripts() is not implemented

What it means

Raised by AbstractStrategy.load_scripts() in redis/cluster.py:4122. In a standalone Redis client, pipelines call SCRIPT LOAD to pre-load Lua scripts so EVALSHA can be used; in Redis Cluster a script must be loaded on every primary, and this method is intentionally left unimplemented on the base strategy. The cluster pipeline handles script loading through a different code path (execute_command of EVAL/EVALSHA), so calling this method directly is a misuse of the API.

Solutions

  1. Remove the explicit load_scripts() call from your cluster pipeline code; let EVAL/EVALSHA handle script loading automatically through execute_command.
  2. If you need a script loaded on all nodes, execute SCRIPT LOAD manually against each primary via rc.cluster_execute_command('SCRIPT LOAD', script, target_nodes='primaries').
  3. Switch to a non-cluster Redis client if you genuinely need the standalone pipeline load_scripts() semantics.

Example fix

// before
pipe = rc.pipeline()
pipe.load_scripts()
// after
# no explicit load_scripts() needed; EVAL/EVALSHA loads lazily
pipe = rc.pipeline()
Defensive patterns

Strategy: validation

Validate before calling

from redis.cluster import RedisCluster
is_cluster = isinstance(rc, RedisCluster)
if not is_cluster:
    pipe.load_scripts()  # safe only on standalone

Type guard

def supports_load_scripts(client) -> bool:
    from redis.cluster import RedisCluster
    return not isinstance(client, RedisCluster)

Try / catch

from redis.exceptions import RedisClusterException
try:
    pipe.load_scripts()
except RedisClusterException:
    pass  # not supported on cluster pipelines

Prevention

When it happens

Trigger: Calling the load_scripts() method directly on a ClusterPipeline instance or on an AbstractStrategy subclass that does not override it: e.g. pipe.load_scripts() where pipe = rc.pipeline() from a RedisCluster client.

Common situations: Code ported verbatim from a standalone redis.Redis pipeline to a redis.cluster.RedisCluster pipeline without removing the explicit SCRIPT LOAD warm-up step; test harnesses that call load_scripts() generically across client types.

Related errors

AI-assisted analysis of redis/redis-py@6a6b581b48 (2026-08-10). Data as JSON: /api/errors/feb1da68ea3962b9. Report an issue: GitHub.

Appendix: source

Thrown at redis/cluster.py:4122

    def send_cluster_commands(
        self, stack, raise_on_error=True, allow_redirections=True
    ):
        pass

    @abstractmethod
    def reset(self):
        pass

    def exists(self, *keys):
        return self.execute_command("EXISTS", *keys)

    def eval(self):
        """ """
        raise RedisClusterException("method eval() is not implemented")

    def load_scripts(self):
        """ """
        raise RedisClusterException("method load_scripts() is not implemented")

    def script_load_for_pipeline(self, *args, **kwargs):
        """ """
        raise RedisClusterException(
            "method script_load_for_pipeline() is not implemented"
        )

    def annotate_exception(self, exception, number, command):
        """
        Provides extra context to the exception prior to it being handled
        """
        cmd = " ".join(map(safe_str, command))
        msg = (
            f"Command # {number} ({truncate_text(cmd)}) of pipeline "
            f"caused error: {exception.args[0]}"
        )
        exception.args = (msg,) + exception.args[1:]

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