Implementation:LMCache LMCache External Connector Adapter

Knowledge Sources	LMCache
Domains	Storage Backend, Plugin System
Last Updated	2026-02-09 00:00 GMT

Overview

ExternalConnectorAdapter dynamically loads user-defined remote connector implementations via URL-based module discovery.

Description

The ExternalConnectorAdapter class extends ConnectorAdapter to support pluggable external connectors. It parses a URL of the form external://host:port/module_path/?connector_name=ConnectorName, dynamically imports the specified Python module using importlib, and instantiates the named connector class. The loaded class must be a subclass of RemoteConnector. Only single-host configurations are supported; comma-separated multi-host URLs raise a ValueError.

Usage

Use this adapter when integrating a custom or third-party key-value store connector that is not natively supported by LMCache. The external connector module must be importable from the Python path and must define a class that inherits from RemoteConnector.

Code Reference

Source Location

Repository: LMCache
File: lmcache/v1/storage_backend/connector/external_adapter.py
Lines: 1-75

Signature

class ExternalConnectorAdapter(ConnectorAdapter):
    def __init__(self) -> None: ...
    def create_connector(self, context: ConnectorContext) -> RemoteConnector: ...

Import

from lmcache.v1.storage_backend.connector.external_adapter import ExternalConnectorAdapter

I/O Contract

Inputs

Name	Type	Required	Description
context	ConnectorContext	Yes	Contains the URL (format: `external://host:port/module_path/?connector_name=ClassName`), event loop, local CPU backend, and config

Outputs

Name	Type	Description
return	RemoteConnector	An instance of the dynamically loaded external connector class

Usage Examples

# URL format for external connectors:
# external://host:0/my_module.my_submodule/?connector_name=MyCustomConnector

# The adapter is typically created via the ConnectorManager auto-discovery:
from lmcache.v1.storage_backend.connector import CreateConnector

connector = CreateConnector(
    url="external://host:0/my_custom_connector.module/?connector_name=MyConnector",
    loop=event_loop,
    local_cpu_backend=cpu_backend,
    config=config,
    metadata=metadata,
)

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