OpenAI DurableRunner with LLM retry opts and lazy session flushing

Author: gvdongen

python/restate/ext/openai/__init__.py

@@ -12,11 +12,34 @@
 This module contains the optional OpenAI integration for Restate.
 """
 
-from .runner_wrapper import Runner, DurableModelCalls, continue_on_terminal_errors, raise_terminal_errors
+import typing
+
+from .runner_wrapper import DurableRunner, continue_on_terminal_errors, raise_terminal_errors, LlmRetryOpts
+from restate import ObjectContext, Context
+from restate.server_context import current_context
+
+
+def restate_object_context() -> ObjectContext:
+    """Get the current Restate ObjectContext."""
+    ctx = current_context()
+    if ctx is None:
+        raise RuntimeError("No Restate context found.")
+    return typing.cast(ObjectContext, ctx)
+
+
+def restate_context() -> Context:
+    """Get the current Restate Context."""
+    ctx = current_context()
+    if ctx is None:
+        raise RuntimeError("No Restate context found.")
+    return ctx
+
 
 __all__ = [
-    "DurableModelCalls",
+    "DurableRunner",
+    "LlmRetryOpts",
+    "restate_object_context",
+    "restate_context",
     "continue_on_terminal_errors",
     "raise_terminal_errors",
-    "Runner",
 ]

python/restate/ext/openai/runner_wrapper.py

@@ -12,40 +12,60 @@
 This module contains the optional OpenAI integration for Restate.
 """
 
-import asyncio
 import dataclasses
-import typing
 
 from agents import (
-    Tool,
     Usage,
     Model,
     RunContextWrapper,
     AgentsException,
-    Runner as OpenAIRunner,
     RunConfig,
     TContext,
     RunResult,
     Agent,
     ModelBehaviorError,
+    ModelSettings,
+    Runner,
 )
-
 from agents.models.multi_provider import MultiProvider
 from agents.items import TResponseStreamEvent, TResponseOutputItem, ModelResponse
 from agents.memory.session import SessionABC
 from agents.items import TResponseInputItem
-from typing import List, Any
-from typing import AsyncIterator
-
-from agents.tool import FunctionTool
-from agents.tool_context import ToolContext
+from datetime import timedelta
+from typing import List, Any, AsyncIterator, Optional, cast
 from pydantic import BaseModel
+
 from restate.exceptions import SdkInternalBaseException
 from restate.extensions import current_context
-
 from restate import RunOptions, ObjectContext, TerminalError
 
 
+@dataclasses.dataclass
+class LlmRetryOpts:
+    max_attempts: Optional[int] = 10
+    """Max number of attempts (including the initial), before giving up.
+
+    When giving up, the LLM call will throw a `TerminalError` wrapping the original error message."""
+    max_duration: Optional[timedelta] = None
+    """Max duration of retries, before giving up.
+
+    When giving up, the LLM call will throw a `TerminalError` wrapping the original error message."""
+    initial_retry_interval: Optional[timedelta] = timedelta(seconds=1)
+    """Initial interval for the first retry attempt.
+    Retry interval will grow by a factor specified in `retry_interval_factor`.
+
+    If any of the other retry related fields is specified, the default for this field is 50 milliseconds, otherwise restate will fallback to the overall invocation retry policy."""
+    max_retry_interval: Optional[timedelta] = None
+    """Max interval between retries.
+    Retry interval will grow by a factor specified in `retry_interval_factor`.
+
+    The default is 10 seconds."""
+    retry_interval_factor: Optional[float] = None
+    """Exponentiation factor to use when computing the next retry delay.
+
+    If any of the other retry related fields is specified, the default for this field is `2`, meaning retry interval will double at each attempt, otherwise restate will fallback to the overall invocation retry policy."""
+
+
 # The OpenAI ModelResponse class is a dataclass with Pydantic fields.
 # The Restate SDK cannot serialize this. So we turn the ModelResponse int a Pydantic model.
 class RestateModelResponse(BaseModel):
@@ -71,23 +91,23 @@ class DurableModelCalls(MultiProvider):
     A Restate model provider that wraps the OpenAI SDK's default MultiProvider.
     """
 
-    def __init__(self, max_retries: int | None = 3):
+    def __init__(self, llm_retry_opts: LlmRetryOpts | None = None):
         super().__init__()
-        self.max_retries = max_retries
+        self.llm_retry_opts = llm_retry_opts
 
     def get_model(self, model_name: str | None) -> Model:
-        return RestateModelWrapper(super().get_model(model_name or None), self.max_retries)
+        return RestateModelWrapper(super().get_model(model_name or None), self.llm_retry_opts)
 
 
 class RestateModelWrapper(Model):
     """
     A wrapper around the OpenAI SDK's Model that persists LLM calls in the Restate journal.
     """
 
-    def __init__(self, model: Model, max_retries: int | None = 3):
+    def __init__(self, model: Model, llm_retry_opts: LlmRetryOpts | None = None):
         self.model = model
         self.model_name = "RestateModelWrapper"
-        self.max_retries = max_retries
+        self.llm_retry_opts = llm_retry_opts if llm_retry_opts is not None else LlmRetryOpts()
 
     async def get_response(self, *args, **kwargs) -> ModelResponse:
         async def call_llm() -> RestateModelResponse:
@@ -102,7 +122,17 @@ async def call_llm() -> RestateModelResponse:
         ctx = current_context()
         if ctx is None:
             raise RuntimeError("No current Restate context found, make sure to run inside a Restate handler")
-        result = await ctx.run_typed("call LLM", call_llm, RunOptions(max_attempts=self.max_retries))
+        result = await ctx.run_typed(
+            "call LLM",
+            call_llm,
+            RunOptions(
+                max_attempts=self.llm_retry_opts.max_attempts,
+                max_duration=self.llm_retry_opts.max_duration,
+                initial_retry_interval=self.llm_retry_opts.initial_retry_interval,
+                max_retry_interval=self.llm_retry_opts.max_retry_interval,
+                retry_interval_factor=self.llm_retry_opts.retry_interval_factor,
+            ),
+        )
         # convert back to original ModelResponse
         return ModelResponse(
             output=result.output,
@@ -117,33 +147,41 @@ def stream_response(self, *args, **kwargs) -> AsyncIterator[TResponseStreamEvent
 class RestateSession(SessionABC):
     """Restate session implementation following the Session protocol."""
 
+    def __init__(self):
+        self._items: List[TResponseInputItem] | None = None
+
     def _ctx(self) -> ObjectContext:
-        return typing.cast(ObjectContext, current_context())
+        return cast(ObjectContext, current_context())
 
     async def get_items(self, limit: int | None = None) -> List[TResponseInputItem]:
         """Retrieve conversation history for this session."""
-        current_items = await self._ctx().get("items", type_hint=List[TResponseInputItem]) or []
+        if self._items is None:
+            self._items = await self._ctx().get("items") or []
         if limit is not None:
-            return current_items[-limit:]
-        return current_items
+            return self._items[-limit:]
+        return self._items.copy()
 
     async def add_items(self, items: List[TResponseInputItem]) -> None:
         """Store new items for this session."""
-        # Your implementation here
-        current_items = await self.get_items() or []
-        self._ctx().set("items", current_items + items)
+        if self._items is None:
+            self._items = await self._ctx().get("items") or []
+        self._items.extend(items)
 
     async def pop_item(self) -> TResponseInputItem | None:
         """Remove and return the most recent item from this session."""
-        current_items = await self.get_items() or []
-        if current_items:
-            item = current_items.pop()
-            self._ctx().set("items", current_items)
-            return item
+        if self._items is None:
+            self._items = await self._ctx().get("items") or []
+        if self._items:
+            return self._items.pop()
         return None
 
+    def flush(self) -> None:
+        """Flush the session items to the context."""
+        self._ctx().set("items", self._items)
+
     async def clear_session(self) -> None:
         """Clear all items for this session."""
+        self._items = []
         self._ctx().clear("items")
 
 
@@ -189,7 +227,7 @@ def continue_on_terminal_errors(context: RunContextWrapper[Any], error: Exceptio
     raise error
 
 
-class Runner:
+class DurableRunner:
     """
     A wrapper around Runner.run that automatically configures RunConfig for Restate contexts.
 
@@ -201,83 +239,55 @@ class Runner:
     @staticmethod
     async def run(
         starting_agent: Agent[TContext],
-        disable_tool_autowrapping: bool = False,
-        *args: typing.Any,
-        run_config: RunConfig | None = None,
+        input: str | list[TResponseInputItem],
+        *,
+        use_restate_session: bool = False,
         **kwargs,
     ) -> RunResult:
         """
         Run an agent with automatic Restate configuration.
 
+        Args:
+            use_restate_session: If True, creates a RestateSession for conversation persistence.
+                                Requires running within a Restate Virtual Object context.
+
         Returns:
             The result from Runner.run
         """
 
-        current_run_config = run_config or RunConfig()
-        new_run_config = dataclasses.replace(
-            current_run_config,
-            model_provider=DurableModelCalls(),
-        )
-        restate_agent = sequentialize_and_wrap_tools(starting_agent, disable_tool_autowrapping)
-        return await OpenAIRunner.run(restate_agent, *args, run_config=new_run_config, **kwargs)
-
-
-def sequentialize_and_wrap_tools(
-    agent: Agent[TContext],
-    disable_tool_autowrapping: bool,
-) -> Agent[TContext]:
-    """
-    Wrap the tools of an agent to use the Restate error handling.
-
-    Returns:
-        A new agent with wrapped tools.
-    """
+        # Set persisting model calls
+        llm_retry_opts = kwargs.pop("llm_retry_opts", None)
+        run_config = kwargs.pop("run_config", RunConfig())
+        run_config = dataclasses.replace(run_config, model_provider=DurableModelCalls(llm_retry_opts))
 
-    # Restate does not allow parallel tool calls, so we use a lock to ensure sequential execution.
-    # This lock only affects tools for this agent; handoff agents are wrapped recursively.
-    sequential_tools_lock = asyncio.Lock()
-    wrapped_tools: list[Tool] = []
-    for tool in agent.tools:
-        if isinstance(tool, FunctionTool):
-
-            def create_wrapper(captured_tool):
-                async def on_invoke_tool_wrapper(tool_context: ToolContext[Any], tool_input: Any) -> Any:
-                    await sequential_tools_lock.acquire()
-
-                    async def invoke():
-                        result = await captured_tool.on_invoke_tool(tool_context, tool_input)
-                        # Ensure Pydantic objects are serialized to dict for LLM compatibility
-                        if hasattr(result, "model_dump"):
-                            return result.model_dump()
-                        elif hasattr(result, "dict"):
-                            return result.dict()
-                        return result
-
-                    try:
-                        if disable_tool_autowrapping:
-                            return await invoke()
-
-                        ctx = current_context()
-                        if ctx is None:
-                            raise RuntimeError(
-                                "No current Restate context found, make sure to run inside a Restate handler"
-                            )
-                        return await ctx.run_typed(captured_tool.name, invoke)
-                    finally:
-                        sequential_tools_lock.release()
-
-                return on_invoke_tool_wrapper
-
-            wrapped_tools.append(dataclasses.replace(tool, on_invoke_tool=create_wrapper(tool)))
+        # Disable parallel tool calls
+        model_settings = run_config.model_settings
+        if model_settings is None:
+            model_settings = ModelSettings(parallel_tool_calls=False)
         else:
-            wrapped_tools.append(tool)
+            model_settings = dataclasses.replace(
+                model_settings,
+                parallel_tool_calls=False,
+            )
+        run_config = dataclasses.replace(
+            run_config,
+            model_settings=model_settings,
+        )
+
+        # Use Restate session if requested, otherwise use provided session
+        session = kwargs.pop("session", None)
+        if use_restate_session:
+            if session is not None:
+                raise TerminalError("When use_restate_session is True, session config cannot be provided.")
+            session = RestateSession()
 
-    handoffs_with_wrapped_tools = []
-    for handoff in agent.handoffs:
-        # recursively wrap tools in handoff agents
-        handoffs_with_wrapped_tools.append(sequentialize_and_wrap_tools(handoff, disable_tool_autowrapping))  # type: ignore
+        try:
+            result = await Runner.run(
+                starting_agent=starting_agent, input=input, run_config=run_config, session=session, **kwargs
+            )
+        finally:
+            # Flush session items to Restate
+            if session is not None and isinstance(session, RestateSession):
+                session.flush()
 
-    return agent.clone(
-        tools=wrapped_tools,
-        handoffs=handoffs_with_wrapped_tools,
-    )
+        return result