Implementation:LMCache LMCache API Registry

Knowledge Sources	LMCache
Domains	API Server, Plugin Discovery
Last Updated	2026-02-09 00:00 GMT

Overview

Automatically discovers and registers FastAPI route modules by category for the LMCache internal API server.

Description

The APIRegistry class provides a convention-based auto-discovery mechanism for API route modules. It scans category subdirectories (common, vllm, controller) under the internal_api_server package, imports any module whose name ends with _api, and includes their APIRouter instances into a parent FastAPI application. This plugin-style architecture allows new API endpoints to be added simply by creating a new *_api.py file in the appropriate category directory. The registry supports selective category registration via the optional categories parameter.

Usage

Use APIRegistry at application startup to wire all API endpoints into the FastAPI app. Instantiate with the FastAPI app, then call register_all_apis with the desired category list. New API modules are automatically discovered without modifying the registry code.

Code Reference

Source Location

• Repository: LMCache
• File: lmcache/v1/internal_api_server/api_registry.py
• Lines: 1-59

Signature

APICategory = Literal["common", "vllm", "controller"]

class APIRegistry:
    def __init__(self, app: FastAPI) -> None: ...
    def register_all_apis(self, categories: Optional[List[APICategory]] = None) -> None: ...

Import

from lmcache.v1.internal_api_server.api_registry import APIRegistry, APICategory

I/O Contract

Inputs

Name	Type	Required	Description
app	FastAPI	Yes	The FastAPI application instance to register routes on
categories	Optional[List[APICategory]]	No	List of categories to register; defaults to all ("common", "vllm", "controller")

Outputs

Name	Type	Description
(side effect)	None	API routes from discovered modules are included into the FastAPI app

Usage Examples

from fastapi import FastAPI
from lmcache.v1.internal_api_server.api_registry import APIRegistry

app = FastAPI()
registry = APIRegistry(app)

# Register all API categories
registry.register_all_apis()

# Or register only specific categories
registry.register_all_apis(categories=["common", "vllm"])