[Core] Support load and unload LoRA in api server (#6566)

Co-authored-by: Jee Jee Li <pandaleefree@gmail.com>

vllm/entrypoints/openai/api_server.py

@@ -35,11 +35,13 @@ from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DetokenizeResponse,
                                               EmbeddingRequest,
                                               EmbeddingResponse, ErrorResponse,
+                                              LoadLoraAdapterRequest,
                                               TokenizeRequest,
-                                              TokenizeResponse)
-# yapf: enable
+                                              TokenizeResponse,
+                                              UnloadLoraAdapterRequest)
 from vllm.entrypoints.openai.rpc.client import AsyncEngineRPCClient
 from vllm.entrypoints.openai.rpc.server import run_rpc_server
+# yapf: enable
 from vllm.entrypoints.openai.serving_chat import OpenAIServingChat
 from vllm.entrypoints.openai.serving_completion import OpenAIServingCompletion
 from vllm.entrypoints.openai.serving_embedding import OpenAIServingEmbedding
@@ -343,6 +345,40 @@ if envs.VLLM_TORCH_PROFILER_DIR:
         return Response(status_code=200)
 
 
+if envs.VLLM_ALLOW_RUNTIME_LORA_UPDATING:
+    logger.warning(
+        "Lora dynamic loading & unloading is enabled in the API server. "
+        "This should ONLY be used for local development!")
+
+    @router.post("/v1/load_lora_adapter")
+    async def load_lora_adapter(request: LoadLoraAdapterRequest):
+        response = await openai_serving_chat.load_lora_adapter(request)
+        if isinstance(response, ErrorResponse):
+            return JSONResponse(content=response.model_dump(),
+                                status_code=response.code)
+
+        response = await openai_serving_completion.load_lora_adapter(request)
+        if isinstance(response, ErrorResponse):
+            return JSONResponse(content=response.model_dump(),
+                                status_code=response.code)
+
+        return Response(status_code=200, content=response)
+
+    @router.post("/v1/unload_lora_adapter")
+    async def unload_lora_adapter(request: UnloadLoraAdapterRequest):
+        response = await openai_serving_chat.unload_lora_adapter(request)
+        if isinstance(response, ErrorResponse):
+            return JSONResponse(content=response.model_dump(),
+                                status_code=response.code)
+
+        response = await openai_serving_completion.unload_lora_adapter(request)
+        if isinstance(response, ErrorResponse):
+            return JSONResponse(content=response.model_dump(),
+                                status_code=response.code)
+
+        return Response(status_code=200, content=response)
+
+
 def build_app(args: Namespace) -> FastAPI:
     app = FastAPI(lifespan=lifespan)
     app.include_router(router)