feat(bus): add correlation store for request-response

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

nanobot/bus/queue.py

@@ -16,6 +16,9 @@ class MessageBus:
     def __init__(self):
         self.inbound: asyncio.Queue[InboundMessage] = asyncio.Queue()
         self.outbound: asyncio.Queue[OutboundMessage] = asyncio.Queue()
+        self._outbound_subscribers: dict[str, list[Callable[[OutboundMessage], Awaitable[None]]]] = {}
+        self._correlation_store: dict[str, asyncio.Future] = {}
+        self._running = False
 
     async def publish_inbound(self, msg: InboundMessage) -> None:
         """Publish a message from a channel to the agent."""
@@ -33,6 +36,60 @@ class MessageBus:
         """Consume the next outbound message (blocks until available)."""
         return await self.outbound.get()
 
+    def register_correlation(self, correlation_id: str) -> asyncio.Future:
+        """Register a Future to be resolved when a matching outbound message appears."""
+        loop = asyncio.get_running_loop()
+        future = loop.create_future()
+        self._correlation_store[correlation_id] = future
+        return future
+
+    def resolve_correlation(self, msg: OutboundMessage) -> None:
+        """Check if an outbound message has a correlation_id and resolve the matching Future."""
+        cid = msg.metadata.get("correlation_id") if msg.metadata else None
+        if cid and cid in self._correlation_store:
+            future = self._correlation_store.pop(cid)
+            if not future.done():
+                future.set_result(msg.content)
+
+    def cancel_correlation(self, correlation_id: str) -> None:
+        """Cancel and remove a pending correlation."""
+        future = self._correlation_store.pop(correlation_id, None)
+        if future and not future.done():
+            future.cancel()
+
+    def subscribe_outbound(
+        self, 
+        channel: str, 
+        callback: Callable[[OutboundMessage], Awaitable[None]]
+    ) -> None:
+        """Subscribe to outbound messages for a specific channel."""
+        if channel not in self._outbound_subscribers:
+            self._outbound_subscribers[channel] = []
+        self._outbound_subscribers[channel].append(callback)
+    
+    async def dispatch_outbound(self) -> None:
+        """
+        Dispatch outbound messages to subscribed channels.
+        Run this as a background task.
+        """
+        self._running = True
+        while self._running:
+            try:
+                msg = await asyncio.wait_for(self.outbound.get(), timeout=1.0)
+                subscribers = self._outbound_subscribers.get(msg.channel, [])
+                for callback in subscribers:
+                    try:
+                        await callback(msg)
+                    except Exception as e:
+                        logger.error(f"Error dispatching to {msg.channel}: {e}")
+            except asyncio.TimeoutError:
+                continue
+    
+    def stop(self) -> None:
+        """Stop the dispatcher loop."""
+        self._running = False
+    
+>>>>>>> e5bad4e (feat(bus): add correlation store for request-response)
     @property
     def inbound_size(self) -> int:
         """Number of pending inbound messages."""

tests/test_bus_correlation.py

@@ -0,0 +1,59 @@
+"""Tests for bus-level correlation (request-response via Futures)."""
+
+import asyncio
+import pytest
+from nanobot.bus.queue import MessageBus
+from nanobot.bus.events import OutboundMessage
+
+
+@pytest.fixture
+def bus():
+    return MessageBus()
+
+
+@pytest.mark.asyncio
+async def test_register_correlation_returns_future(bus):
+    future = bus.register_correlation("test-id-1")
+    assert isinstance(future, asyncio.Future)
+    assert not future.done()
+
+
+@pytest.mark.asyncio
+async def test_resolve_correlation_sets_future_result(bus):
+    future = bus.register_correlation("test-id-1")
+    msg = OutboundMessage(channel="hook", chat_id="test", content="hello", metadata={"correlation_id": "test-id-1"})
+    bus.resolve_correlation(msg)
+    assert future.done()
+    assert future.result() == "hello"
+
+
+@pytest.mark.asyncio
+async def test_resolve_correlation_no_match_is_noop(bus):
+    future = bus.register_correlation("test-id-1")
+    msg = OutboundMessage(channel="hook", chat_id="test", content="hello", metadata={"correlation_id": "other-id"})
+    bus.resolve_correlation(msg)
+    assert not future.done()
+
+
+@pytest.mark.asyncio
+async def test_resolve_correlation_no_metadata_is_noop(bus):
+    future = bus.register_correlation("test-id-1")
+    msg = OutboundMessage(channel="hook", chat_id="test", content="hello")
+    bus.resolve_correlation(msg)
+    assert not future.done()
+
+
+@pytest.mark.asyncio
+async def test_resolve_correlation_cleans_up_store(bus):
+    future = bus.register_correlation("test-id-1")
+    msg = OutboundMessage(channel="hook", chat_id="test", content="hello", metadata={"correlation_id": "test-id-1"})
+    bus.resolve_correlation(msg)
+    assert "test-id-1" not in bus._correlation_store
+
+
+@pytest.mark.asyncio
+async def test_cancel_correlation(bus):
+    future = bus.register_correlation("test-id-1")
+    bus.cancel_correlation("test-id-1")
+    assert "test-id-1" not in bus._correlation_store
+    assert future.cancelled()