Improve error handling for requests with unloaded LoRA path(s) (#7642)

python/sglang/srt/managers/tokenizer_manager.py

@@ -240,6 +240,12 @@ class TokenizerManager:
                     revision=server_args.revision,
                 )
 
+        # Initialize loaded loRA adapters with the initial lora paths in the server_args.
+        # This list will be updated when new LoRA adapters are loaded or unloaded dynamically.
+        self.loaded_lora_adapters: Dict[str, str] = dict(
+            self.server_args.lora_paths or {}
+        )
+
         # Store states
         self.no_create_loop = False
         self.rid_to_state: Dict[str, ReqState] = {}
@@ -549,6 +555,8 @@ class TokenizerManager:
                     "The server is not configured to enable custom logit processor. "
                     "Please set `--enable-custom-logits-processor` to enable this feature."
                 )
+            if self.server_args.lora_paths and obj.lora_path:
+                self._validate_lora_adapters(obj)
 
     def _validate_input_ids_in_vocab(
         self, input_ids: List[int], vocab_size: int
@@ -662,6 +670,21 @@ class TokenizerManager:
                     "Batch tokenization is not needed for input_embeds. Do not set `enable_tokenizer_batch_encode`."
                 )
 
+    def _validate_lora_adapters(self, obj: GenerateReqInput):
+        """Validate that the requested LoRA adapters are loaded."""
+        requested_adapters = (
+            set(obj.lora_path) if isinstance(obj.lora_path, list) else {obj.lora_path}
+        )
+        loaded_adapters = (
+            self.loaded_lora_adapters.keys() if self.loaded_lora_adapters else set()
+        )
+        unloaded_adapters = requested_adapters - loaded_adapters
+        if unloaded_adapters:
+            raise ValueError(
+                f"The following requested LoRA adapters are not loaded: {unloaded_adapters}\n"
+                f"Loaded adapters: {loaded_adapters}."
+            )
+
     def _send_one_request(
         self,
         obj: Union[GenerateReqInput, EmbeddingReqInput],
@@ -988,6 +1011,7 @@ class TokenizerManager:
 
         async with self.model_update_lock.writer_lock:
             result = (await self.update_lora_adapter_communicator(obj))[0]
+            self.loaded_lora_adapters = result.loaded_adapters
             return result
 
     async def unload_lora_adapter(
@@ -1009,6 +1033,7 @@ class TokenizerManager:
 
         async with self.model_update_lock.writer_lock:
             result = (await self.update_lora_adapter_communicator(obj))[0]
+            self.loaded_lora_adapters = result.loaded_adapters
             return result
 
     async def get_weights_by_name(

python/sglang/srt/server_args.py

@@ -20,7 +20,7 @@ import logging
 import os
 import random
 import tempfile
-from typing import List, Literal, Optional
+from typing import List, Literal, Optional, Union
 
 from sglang.srt.hf_transformers_utils import check_gguf_file, get_config
 from sglang.srt.reasoning_parser import ReasoningParser
@@ -131,7 +131,7 @@ class ServerArgs:
     preferred_sampling_params: Optional[str] = None
 
     # LoRA
-    lora_paths: Optional[List[str]] = None
+    lora_paths: Optional[Union[dict[str, str], List[str]]] = None
     max_loras_per_batch: int = 8
     lora_backend: str = "triton"