[gRPC] Stream engine state changes (#39915)

Signed-off-by: William Arnold <7565007+Aphoh@users.noreply.github.com>
Co-authored-by: ishandhanani <82981111+ishandhanani@users.noreply.github.com>

python/sglang/srt/entrypoints/grpc_bridge.py

@@ -84,6 +84,9 @@ class RuntimeHandle:
         self.tokenizer_manager.auto_create_handle_loop()
         self._event_loop = self.tokenizer_manager.event_loop
 
+    def set_engine_state_changed_callback(self, callback) -> None:
+        self.tokenizer_manager.set_engine_state_changed_callback(callback)
+
     @property
     def _tm_loop(self):
         """Return the TokenizerManager loop used by communicator RPCs."""
@@ -449,8 +452,9 @@ class RuntimeHandle:
             ServerStatus.UnHealthy,
         )
 
-    def get_is_ready(self) -> bool:
-        return self.tokenizer_manager.is_ready()
+    def is_pause(self) -> bool:
+        """Return the tokenizer manager's authoritative generation pause state."""
+        return self.tokenizer_manager.is_pause
 
     def tokenize(self, text: str, add_special_tokens: bool = True) -> str:
         tokenizer = self.tokenizer_manager.tokenizer

python/sglang/srt/managers/tokenizer_manager.py

@@ -416,10 +416,53 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
     # Set by whoever owns the event loop, and left None for Engine and grpc,
     # which own no server. Class-level to leave the frozen __init__ alone.
     _server_stop_hook: Optional[Callable[[], None]] = None
+    _engine_state_changed_callback: Optional[Callable[[], None]] = None
 
     def set_server_stop_hook(self, hook: Callable[[], None]) -> None:
         self._server_stop_hook = hook
 
+    def _notify_engine_state_changed(self) -> None:
+        callback = self._engine_state_changed_callback
+        if callback is None:
+            return
+        try:
+            callback()
+        except Exception:
+            logger.exception("Engine-state change callback failed")
+
+    def _set_engine_state_field(self, name: str, value: Any) -> None:
+        if value == getattr(self, name, None):
+            return
+        setattr(self, name, value)
+        self._notify_engine_state_changed()
+
+    def set_engine_state_changed_callback(self, callback: Callable[[], None]) -> None:
+        self._engine_state_changed_callback = callback
+
+    @property
+    def server_status(self):
+        return self._server_status
+
+    @server_status.setter
+    def server_status(self, value) -> None:
+        self._set_engine_state_field("_server_status", value)
+
+    @property
+    def gracefully_exit(self) -> bool:
+        return self._gracefully_exit
+
+    @gracefully_exit.setter
+    def gracefully_exit(self, value: bool) -> None:
+        self._set_engine_state_field("_gracefully_exit", value)
+
+    @property
+    def is_pause(self) -> bool:
+        return self._is_pause
+
+    @is_pause.setter
+    def is_pause(self, value: bool) -> None:
+        self._set_engine_state_field("_is_pause", value)
+
     @property
     def serving_chat_class(self):
         """Return the serving chat class for OpenAI API.