Initial commit

libs/events/memory_bus.py

@@ -0,0 +1,64 @@
+"""In-memory event bus for local development and testing."""
+
+import asyncio
+import logging
+from collections import defaultdict
+from collections.abc import Awaitable, Callable
+
+from .base import EventBus, EventPayload
+
+logger = logging.getLogger(__name__)
+
+
+class MemoryEventBus(EventBus):
+    """In-memory event bus implementation for local development"""
+
+    def __init__(self) -> None:
+        self.handlers: dict[
+            str, list[Callable[[str, EventPayload], Awaitable[None]]]
+        ] = defaultdict(list)
+        self.running = False
+
+    async def publish(self, topic: str, payload: EventPayload) -> bool:
+        """Publish event to topic"""
+        try:
+            if not self.running:
+                logger.warning(
+                    "Event bus not running, skipping publish to topic: %s", topic
+                )
+                return False
+
+            handlers = self.handlers.get(topic, [])
+            if not handlers:
+                logger.debug("No handlers for topic: %s", topic)
+                return True
+
+            # Execute all handlers concurrently
+            tasks = [handler(topic, payload) for handler in handlers]
+            await asyncio.gather(*tasks, return_exceptions=True)
+
+            logger.debug(
+                "Published event to topic %s with %d handlers", topic, len(handlers)
+            )
+            return True
+        except Exception as e:
+            logger.error("Failed to publish event to topic %s: %s", topic, e)
+            return False
+
+    async def subscribe(
+        self, topic: str, handler: Callable[[str, EventPayload], Awaitable[None]]
+    ) -> None:
+        """Subscribe to topic with handler"""
+        self.handlers[topic].append(handler)
+        logger.debug("Subscribed handler to topic: %s", topic)
+
+    async def start(self) -> None:
+        """Start the event bus"""
+        self.running = True
+        logger.info("Memory event bus started")
+
+    async def stop(self) -> None:
+        """Stop the event bus"""
+        self.running = False
+        self.handlers.clear()
+        logger.info("Memory event bus stopped")