Feature/Add GET endpoint to query loaded LoRA adapters (#12229)

python/sglang/srt/entrypoints/http_server.py

@@ -1168,6 +1168,8 @@ async def available_models():
     """Show available models. OpenAI-compatible endpoint."""
     served_model_names = [_global_state.tokenizer_manager.served_model_name]
     model_cards = []
+
+    # Add base model
     for served_model_name in served_model_names:
         model_cards.append(
             ModelCard(
@@ -1176,6 +1178,20 @@ async def available_models():
                 max_model_len=_global_state.tokenizer_manager.model_config.context_len,
             )
         )
+
+    # Add loaded LoRA adapters
+    if _global_state.tokenizer_manager.server_args.enable_lora:
+        lora_registry = _global_state.tokenizer_manager.lora_registry
+        for _, lora_ref in lora_registry.get_all_adapters().items():
+            model_cards.append(
+                ModelCard(
+                    id=lora_ref.lora_name,
+                    root=lora_ref.lora_path,
+                    parent=served_model_names[0],
+                    max_model_len=None,
+                )
+            )
+
     return ModelList(data=model_cards)
 
 

python/sglang/srt/entrypoints/openai/protocol.py

@@ -54,6 +54,7 @@ class ModelCard(BaseModel):
     created: int = Field(default_factory=lambda: int(time.time()))
     owned_by: str = "sglang"
     root: Optional[str] = None
+    parent: Optional[str] = None
     max_model_len: Optional[int] = None
 
 

python/sglang/srt/lora/lora_registry.py

@@ -205,3 +205,12 @@ class LoRARegistry:
         Returns the total number of LoRA adapters currently registered.
         """
         return len(self._registry)
+
+    def get_all_adapters(self) -> Dict[str, LoRARef]:
+        """
+        Returns a dictionary of all registered LoRA adapters.
+
+        Returns:
+            Dict[str, LoRARef]: A dictionary mapping LoRA names to LoRARef objects.
+        """
+        return dict(self._registry)

test/srt/lora/test_lora_update.py

@@ -1328,6 +1328,78 @@ class TestLoRADynamicUpdate(CustomTestCase):
             mode=LoRAUpdateTestSessionMode.SERVER, test_cases=test_cases
         )
 
+    def test_v1_models_endpoint_with_lora(self):
+        """
+        Test that /v1/models endpoint returns base model and loaded LoRA adapters.
+        """
+        adapters = [
+            "philschmid/code-llama-3-1-8b-text-to-sql-lora",
+            "Nutanix/Meta-Llama-3.1-8B-Instruct_lora_4_alpha_16",
+        ]
+
+        with LoRAUpdateTestSession(
+            testcase=self,
+            mode=LoRAUpdateTestSessionMode.SERVER,
+            model_path="meta-llama/Llama-3.1-8B-Instruct",
+            lora_paths=[],
+            max_loras_per_batch=2,
+            max_lora_rank=256,
+            lora_target_modules=["all"],
+            enable_lora=True,
+        ) as session:
+            # Test with no adapters loaded
+            response = requests.get(DEFAULT_URL_FOR_TEST + "/v1/models")
+            self.assertTrue(response.ok, response.text)
+            models_data = response.json()
+            self.assertEqual(models_data["object"], "list")
+            self.assertEqual(len(models_data["data"]), 1)  # Only base model
+            base_model = models_data["data"][0]
+            self.assertIn("meta-llama", base_model["id"].lower())
+            self.assertIsNone(base_model.get("parent"))
+
+            # Load first adapter
+            session.load_lora_adapter(lora_name="adapter1", lora_path=adapters[0])
+
+            # Test with one adapter loaded
+            response = requests.get(DEFAULT_URL_FOR_TEST + "/v1/models")
+            self.assertTrue(response.ok, response.text)
+            models_data = response.json()
+            self.assertEqual(len(models_data["data"]), 2)  # Base model + 1 adapter
+
+            # Verify adapter information
+            adapter_models = [m for m in models_data["data"] if m.get("parent")]
+            self.assertEqual(len(adapter_models), 1)
+            self.assertEqual(adapter_models[0]["id"], "adapter1")
+            self.assertEqual(adapter_models[0]["root"], adapters[0])
+            self.assertIsNotNone(adapter_models[0]["parent"])
+
+            # Load second adapter
+            session.load_lora_adapter(lora_name="adapter2", lora_path=adapters[1])
+
+            # Test with two adapters loaded
+            response = requests.get(DEFAULT_URL_FOR_TEST + "/v1/models")
+            self.assertTrue(response.ok, response.text)
+            models_data = response.json()
+            self.assertEqual(len(models_data["data"]), 3)  # Base model + 2 adapters
+
+            # Verify both adapters are listed
+            adapter_models = [m for m in models_data["data"] if m.get("parent")]
+            self.assertEqual(len(adapter_models), 2)
+            adapter_names = {m["id"] for m in adapter_models}
+            self.assertEqual(adapter_names, {"adapter1", "adapter2"})
+
+            # Unload one adapter
+            session.unload_lora_adapter(lora_name="adapter1")
+
+            # Test after unloading
+            response = requests.get(DEFAULT_URL_FOR_TEST + "/v1/models")
+            self.assertTrue(response.ok, response.text)
+            models_data = response.json()
+            self.assertEqual(len(models_data["data"]), 2)  # Base model + 1 adapter
+            adapter_models = [m for m in models_data["data"] if m.get("parent")]
+            self.assertEqual(len(adapter_models), 1)
+            self.assertEqual(adapter_models[0]["id"], "adapter2")
+
 
 if __name__ == "__main__":
     try: