chore: import upstream snapshot with attribution

python/semantic_kernel/agents/runtime/in_process/default_subscription.py

@@ -0,0 +1,65 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+from collections.abc import Callable
+from typing import TypeVar, overload
+
+from semantic_kernel.agents.runtime.core.agent_type import AgentType
+from semantic_kernel.agents.runtime.core.base_agent import BaseAgent, subscription_factory
+from semantic_kernel.agents.runtime.core.exceptions import CantHandleException
+from semantic_kernel.agents.runtime.in_process.subscription_context import SubscriptionInstantiationContext
+from semantic_kernel.agents.runtime.in_process.type_subscription import TypeSubscription
+from semantic_kernel.utils.feature_stage_decorator import experimental
+
+
+@experimental
+class DefaultSubscription(TypeSubscription):
+    """The default subscription is designed to be a default for applications that only need global scope for agents.
+
+    This topic by default uses the "default" topic type and attempts to detect the agent type to use based on the
+    instantiation context.
+
+    Args:
+        topic_type (str, optional): The topic type to subscribe to. Defaults to "default".
+        agent_type (str, optional): The agent type to use for the subscription. Defaults to None, in which case it
+            will attempt to detect the agent type based on the instantiation context.
+    """
+
+    def __init__(self, topic_type: str = "default", agent_type: str | AgentType | None = None):
+        """Initialize the DefaultSubscription."""
+        if agent_type is None:
+            try:
+                agent_type = SubscriptionInstantiationContext.agent_type().type
+            except RuntimeError as e:
+                raise CantHandleException(
+                    "If agent_type is not specified DefaultSubscription must be created within the subscription "
+                    "callback in AgentRuntime.register"
+                ) from e
+
+        super().__init__(topic_type, agent_type)
+
+
+BaseAgentType = TypeVar("BaseAgentType", bound="BaseAgent")
+
+
+@overload
+def default_subscription() -> Callable[[type[BaseAgentType]], type[BaseAgentType]]: ...
+
+
+@overload
+def default_subscription(cls: type[BaseAgentType]) -> type[BaseAgentType]: ...
+
+
+@experimental
+def default_subscription(
+    cls: type[BaseAgentType] | None = None,
+) -> Callable[[type[BaseAgentType]], type[BaseAgentType]] | type[BaseAgentType]:
+    """Create a default subscription."""
+    if cls is None:
+        return subscription_factory(lambda: [DefaultSubscription()])
+    return subscription_factory(lambda: [DefaultSubscription()])(cls)
+
+
+@experimental
+def type_subscription(topic_type: str) -> Callable[[type[BaseAgentType]], type[BaseAgentType]]:
+    """Create a type subscription for the given topic type."""
+    return subscription_factory(lambda: [DefaultSubscription(topic_type=topic_type)])