Support server based rollout in Verlengine (#4848)

Co-authored-by: Jin Pan <jpan236@wisc.edu>
Co-authored-by: Chayenne <zhaochen20@outlook.com>
Co-authored-by: Jinn <47354855+jhinpan@users.noreply.github.com>

python/sglang/srt/entrypoints/EngineBase.py

@@ -0,0 +1,53 @@
+from abc import ABC, abstractmethod
+from typing import Dict, Iterator, List, Optional, Tuple, Union
+
+import torch
+
+
+class EngineBase(ABC):
+    """
+    Abstract base class for engine interfaces that support generation, weight updating, and memory control.
+    This base class provides a unified API for both HTTP-based engines and engines.
+    """
+
+    @abstractmethod
+    def generate(
+        self,
+        prompt: Optional[Union[List[str], str]] = None,
+        sampling_params: Optional[Union[List[Dict], Dict]] = None,
+        input_ids: Optional[Union[List[List[int]], List[int]]] = None,
+        image_data: Optional[Union[List[str], str]] = None,
+        return_logprob: Optional[Union[List[bool], bool]] = False,
+        logprob_start_len: Optional[Union[List[int], int]] = None,
+        top_logprobs_num: Optional[Union[List[int], int]] = None,
+        token_ids_logprob: Optional[Union[List[List[int]], List[int]]] = None,
+        lora_path: Optional[Union[List[Optional[str]], Optional[str]]] = None,
+        custom_logit_processor: Optional[Union[List[str], str]] = None,
+    ) -> Union[Dict, Iterator[Dict]]:
+        """Generate outputs based on given inputs."""
+        pass
+
+    @abstractmethod
+    def update_weights_from_tensor(
+        self,
+        named_tensors: List[Tuple[str, torch.Tensor]],
+        load_format: Optional[str] = None,
+        flush_cache: bool = True,
+    ):
+        """Update model weights with in-memory tensor data."""
+        pass
+
+    @abstractmethod
+    def release_memory_occupation(self):
+        """Release GPU memory occupation temporarily."""
+        pass
+
+    @abstractmethod
+    def resume_memory_occupation(self):
+        """Resume GPU memory occupation which is previously released."""
+        pass
+
+    @abstractmethod
+    def shutdown(self):
+        """Shutdown the engine and clean up resources."""
+        pass