Add ability to register Agent instances

python/packages/autogen-core/src/autogen_core/_agent.py

@@ -1,9 +1,13 @@
-from typing import Any, Mapping, Protocol, runtime_checkable
+from typing import TYPE_CHECKING, Any, Mapping, Protocol, runtime_checkable
 
 from ._agent_id import AgentId
 from ._agent_metadata import AgentMetadata
 from ._message_context import MessageContext
 
+# Forward declaration for type checking only
+if TYPE_CHECKING:
+    from ._agent_runtime import AgentRuntime
+
 
 @runtime_checkable
 class Agent(Protocol):
@@ -17,6 +21,15 @@
         """ID of the agent."""
         ...
 
+    async def bind_id_and_runtime(self, id: AgentId, runtime: "AgentRuntime") -> None:
+        """Function used to bind an Agent instance to an `AgentRuntime`.
+
+        Args:
+            agent_id (AgentId): ID of the agent.
+            runtime (AgentRuntime): AgentRuntime instance to bind the agent to.
+        """
+        ...
+
     async def on_message(self, message: Any, ctx: MessageContext) -> Any:
         """Message handler for the agent. This should only be called by the runtime, not by other agents.
 

python/packages/autogen-core/src/autogen_core/_agent_instantiation.py

@@ -118,3 +118,9 @@ def current_agent_id(cls) -> AgentId:
             raise RuntimeError(
                 "AgentInstantiationContext.agent_id() must be called within an instantiation context such as when the AgentRuntime is instantiating an agent. Mostly likely this was caused by directly instantiating an agent instead of using the AgentRuntime to do so."
             ) from e
+
+    @classmethod
+    def is_in_factory_call(cls) -> bool:
+        if cls._AGENT_INSTANTIATION_CONTEXT_VAR.get(None) is None:
+            return False
+        return True

python/packages/autogen-core/src/autogen_core/_agent_runtime.py

@@ -130,6 +130,60 @@
         """
         ...
 
+    async def register_agent_instance(
+        self,
+        agent_instance: Agent,
+        agent_id: AgentId,
+    ) -> AgentId:
+        """Register an agent instance with the runtime. The type may be reused, but each agent_id must be unique. All agent instances within a type must be of the same object type. This API does not add any subscriptions.
+
+        .. note::
+
+            This is a low level API and usually the agent class's `register_instance` method should be used instead, as this also handles subscriptions automatically.
+
+        Example:
+
+        .. code-block:: python
+
+            from dataclasses import dataclass
+
+            from autogen_core import AgentId, AgentRuntime, MessageContext, RoutedAgent, event
+            from autogen_core.models import UserMessage
+
+
+            @dataclass
+            class MyMessage:
+                content: str
+
+
+            class MyAgent(RoutedAgent):
+                def __init__(self) -> None:
+                    super().__init__("My core agent")
+
+                @event
+                async def handler(self, message: UserMessage, context: MessageContext) -> None:
+                    print("Event received: ", message.content)
+
+
+            async def main() -> None:
+                runtime: AgentRuntime = ...  # type: ignore
+                agent = MyAgent()
+                await runtime.register_agent_instance(
+                    agent_instance=agent, agent_id=AgentId(type="my_agent", key="default")
+                )
+
+
+            import asyncio
+
+            asyncio.run(main())
+
+
+        Args:
+            agent_instance (Agent): A concrete instance of the agent.
+            agent_id (AgentId): The agent's identifier. The agent's type is `agent_id.type`.
+        """
+        ...
+
     # TODO: uncomment out the following type ignore when this is fixed in mypy: https://github.com/python/mypy/issues/3737
     async def try_get_underlying_agent_instance(self, id: AgentId, type: Type[T] = Agent) -> T:  # type: ignore[assignment]
         """Try to get the underlying agent instance by name and namespace. This is generally discouraged (hence the long name), but can be useful in some cases.

python/packages/autogen-core/src/autogen_core/_base_agent.py

@@ -21,6 +21,7 @@
 from ._subscription_context import SubscriptionInstantiationContext
 from ._topic import TopicId
 from ._type_prefix_subscription import TypePrefixSubscription
+from ._type_subscription import TypeSubscription
 
 T = TypeVar("T", bound=Agent)
 
@@ -82,20 +83,25 @@
         return AgentMetadata(key=self._id.key, type=self._id.type, description=self._description)
 
     def __init__(self, description: str) -> None:
-        try:
-            runtime = AgentInstantiationContext.current_runtime()
-            id = AgentInstantiationContext.current_agent_id()
-        except LookupError as e:
-            raise RuntimeError(
-                "BaseAgent must be instantiated within the context of an AgentRuntime. It cannot be directly instantiated."
-            ) from e
-
-        self._runtime: AgentRuntime = runtime
-        self._id: AgentId = id
+        if AgentInstantiationContext.is_in_factory_call():
+            self._runtime: AgentRuntime = AgentInstantiationContext.current_runtime()
+            self._id = AgentInstantiationContext.current_agent_id()
         if not isinstance(description, str):
             raise ValueError("Agent description must be a string")
         self._description = description
 
+    async def bind_id_and_runtime(self, id: AgentId, runtime: AgentRuntime) -> None:
+        if hasattr(self, "_id"):
+            if self._id != id:
+                raise RuntimeError("Agent is already bound to a different ID")
+
+        if hasattr(self, "_runtime"):
+            if self._runtime != runtime:
+                raise RuntimeError("Agent is already bound to a different runtime")
+
+        self._id = id
+        self._runtime = runtime
+
     @property
     def type(self) -> str:
         return self.id.type
@@ -155,6 +161,56 @@
     async def close(self) -> None:
         pass
 
+    async def register_instance(
+        self,
+        runtime: AgentRuntime,
+        agent_id: AgentId,
+        *,
+        skip_class_subscriptions: bool = True,
+        skip_direct_message_subscription: bool = False,
+    ) -> AgentId:
+        """
+        This function is similar to `register` but is used for registering an instance of an agent. A subscription based on the agent ID is created and added to the runtime.
+        """
+        agent_id = await runtime.register_agent_instance(agent_instance=self, agent_id=agent_id)
+
+        id_subscription = TypeSubscription(topic_type=agent_id.key, agent_type=agent_id.type)
+        await runtime.add_subscription(id_subscription)
+
+        if not skip_class_subscriptions:
+            with SubscriptionInstantiationContext.populate_context(AgentType(agent_id.type)):
+                subscriptions: List[Subscription] = []
+                for unbound_subscription in self._unbound_subscriptions():
+                    subscriptions_list_result = unbound_subscription()
+                    if inspect.isawaitable(subscriptions_list_result):
+                        subscriptions_list = await subscriptions_list_result
+                    else:
+                        subscriptions_list = subscriptions_list_result
+
+                    subscriptions.extend(subscriptions_list)
+            for subscription in subscriptions:
+                await runtime.add_subscription(subscription)
+
+        if not skip_direct_message_subscription:
+            # Additionally adds a special prefix subscription for this agent to receive direct messages
+            try:
+                await runtime.add_subscription(
+                    TypePrefixSubscription(
+                        # The prefix MUST include ":" to avoid collisions with other agents
+                        topic_type_prefix=agent_id.type + ":",
+                        agent_type=agent_id.type,
+                    )
+                )
+            except ValueError:
+                # We don't care if the subscription already exists
+                pass
+
+        # TODO: deduplication
+        for _message_type, serializer in self._handles_types():
+            runtime.add_message_serializer(serializer)
+
+        return agent_id
+
     @classmethod
     async def register(
         cls,

python/packages/autogen-core/src/autogen_core/_single_threaded_agent_runtime.py

@@ -266,6 +266,7 @@
         self._serialization_registry = SerializationRegistry()
         self._ignore_unhandled_handler_exceptions = ignore_unhandled_exceptions
         self._background_exception: BaseException | None = None
+        self._agent_instance_types: Dict[str, Type[Agent]] = {}
 
     @property
     def unprocessed_messages_count(
@@ -909,6 +910,32 @@
 
         return type
 
+    async def register_agent_instance(
+        self,
+        agent_instance: Agent,
+        agent_id: AgentId,
+    ) -> AgentId:
+        def agent_factory() -> Agent:
+            raise RuntimeError(
+                "Agent factory was invoked for an agent instance that was not registered. This is likely due to the agent type being incorrectly subscribed to a topic. If this exception occurs when publishing a message to the DefaultTopicId, then it is likely that `skip_class_subscriptions` needs to be turned off when registering the agent."
+            )
+
+        if agent_id in self._instantiated_agents:
+            raise ValueError(f"Agent with id {agent_id} already exists.")
+
+        if agent_id.type not in self._agent_factories:
+            self._agent_factories[agent_id.type] = agent_factory
+            self._agent_instance_types[agent_id.type] = type_func_alias(agent_instance)
+        else:
+            if self._agent_factories[agent_id.type].__code__ != agent_factory.__code__:
+                raise ValueError("Agent factories and agent instances cannot be registered to the same type.")
+            if self._agent_instance_types[agent_id.type] != type_func_alias(agent_instance):
+                raise ValueError("Agent instances must be the same object type.")
+
+        await agent_instance.bind_id_and_runtime(id=agent_id, runtime=self)
+        self._instantiated_agents[agent_id] = agent_instance
+        return agent_id
+
     async def _invoke_agent_factory(
         self,
         agent_factory: Callable[[], T | Awaitable[T]] | Callable[[AgentRuntime, AgentId], T | Awaitable[T]],
@@ -930,8 +957,7 @@
                     raise ValueError("Agent factory must take 0 or 2 arguments.")
 
                 if inspect.isawaitable(agent):
-                    return cast(T, await agent)
-
+                    agent = cast(T, await agent)
                 return agent
 
             except BaseException as e:

python/packages/autogen-core/tests/test_base_agent.py

@@ -9,7 +9,7 @@ async def test_base_agent_create(mocker: MockerFixture) -> None:
     runtime = mocker.Mock(spec=AgentRuntime)
 
     # Shows how to set the context for the agent instantiation in a test context
-    with AgentInstantiationContext.populate_context((runtime, AgentId("name", "namespace"))):
-        agent = NoopAgent()
-        assert agent.runtime == runtime
-        assert agent.id == AgentId("name", "namespace")
+    with AgentInstantiationContext.populate_context((runtime, AgentId("name2", "namespace2"))):
+        agent2 = NoopAgent()
+        assert agent2.runtime == runtime
+        assert agent2.id == AgentId("name2", "namespace2")

python/packages/autogen-core/tests/test_runtime.py

@@ -82,6 +82,60 @@ def agent_factory() -> NoopAgent:
     await runtime.register_factory(type=AgentType("name2"), agent_factory=agent_factory, expected_class=NoopAgent)
 
 
+@pytest.mark.asyncio
+async def test_agent_type_register_instance() -> None:
+    runtime = SingleThreadedAgentRuntime()
+    agent1_id = AgentId(type="name", key="default")
+    agent2_id = AgentId(type="name", key="notdefault")
+    agent1 = NoopAgent()
+    agent1_dup = NoopAgent()
+    agent2 = NoopAgent()
+    await agent1.register_instance(runtime=runtime, agent_id=agent1_id)
+    await agent2.register_instance(runtime=runtime, agent_id=agent2_id)
+
+    assert await runtime.try_get_underlying_agent_instance(agent1_id, type=NoopAgent) == agent1
+    assert await runtime.try_get_underlying_agent_instance(agent2_id, type=NoopAgent) == agent2
+    with pytest.raises(ValueError):
+        await agent1_dup.register_instance(runtime=runtime, agent_id=agent1_id)
+
+
+@pytest.mark.asyncio
+async def test_agent_type_register_instance_different_types() -> None:
+    runtime = SingleThreadedAgentRuntime()
+    agent_id1 = AgentId(type="name", key="noop")
+    agent_id2 = AgentId(type="name", key="loopback")
+    agent1 = NoopAgent()
+    agent2 = LoopbackAgent()
+    await agent1.register_instance(runtime=runtime, agent_id=agent_id1)
+    with pytest.raises(ValueError):
+        await agent2.register_instance(runtime=runtime, agent_id=agent_id2)
+
+
+@pytest.mark.asyncio
+async def test_agent_type_register_instance_publish_new_source() -> None:
+    runtime = SingleThreadedAgentRuntime(ignore_unhandled_exceptions=False)
+    agent_id = AgentId(type="name", key="default")
+    agent1 = LoopbackAgent()
+    await agent1.register_instance(runtime=runtime, agent_id=agent_id)
+    await runtime.add_subscription(TypeSubscription("notdefault", "name"))
+
+    runtime.start()
+    with pytest.raises(RuntimeError):
+        await runtime.publish_message(MessageType(), TopicId("notdefault", "notdefault"))
+        await runtime.stop_when_idle()
+    await runtime.close()
+
+
+@pytest.mark.asyncio
+async def test_register_instance_factory() -> None:
+    runtime = SingleThreadedAgentRuntime()
+    agent1_id = AgentId(type="name", key="default")
+    agent1 = NoopAgent()
+    await agent1.register_instance(runtime=runtime, agent_id=agent1_id)
+    with pytest.raises(ValueError):
+        await NoopAgent.register(runtime, "name", lambda: NoopAgent())
+
+
 @pytest.mark.asyncio
 async def test_register_receives_publish(tracer_provider: TracerProvider) -> None:
     runtime = SingleThreadedAgentRuntime(tracer_provider=tracer_provider)