remove infra.md.example, infra.md is the source of truth

ayn-antivirus/ayn_antivirus/core/event_bus.py

@@ -0,0 +1,119 @@
+"""Simple publish/subscribe event bus for AYN Antivirus.
+
+Decouples the scan engine from consumers like the CLI, logger, quarantine
+manager, and real-time monitor so each component can react to events
+independently.
+"""
+
+from __future__ import annotations
+
+import logging
+import threading
+from enum import Enum, auto
+from typing import Any, Callable, Dict, List
+
+logger = logging.getLogger(__name__)
+
+
+# ---------------------------------------------------------------------------
+# Event types
+# ---------------------------------------------------------------------------
+class EventType(Enum):
+    """All events emitted by the AYN engine."""
+
+    THREAT_FOUND = auto()
+    SCAN_STARTED = auto()
+    SCAN_COMPLETED = auto()
+    FILE_SCANNED = auto()
+    SIGNATURE_UPDATED = auto()
+    QUARANTINE_ACTION = auto()
+    REMEDIATION_ACTION = auto()
+    DASHBOARD_METRIC = auto()
+
+
+# Type alias for subscriber callbacks.
+Callback = Callable[[EventType, Any], None]
+
+
+# ---------------------------------------------------------------------------
+# EventBus
+# ---------------------------------------------------------------------------
+class EventBus:
+    """Thread-safe publish/subscribe event bus.
+
+    Usage::
+
+        bus = EventBus()
+        bus.subscribe(EventType.THREAT_FOUND, lambda et, data: print(data))
+        bus.publish(EventType.THREAT_FOUND, {"path": "/tmp/evil.elf"})
+    """
+
+    def __init__(self) -> None:
+        self._subscribers: Dict[EventType, List[Callback]] = {et: [] for et in EventType}
+        self._lock = threading.Lock()
+
+    # ------------------------------------------------------------------
+    # Public API
+    # ------------------------------------------------------------------
+    def subscribe(self, event_type: EventType, callback: Callback) -> None:
+        """Register *callback* to be invoked whenever *event_type* is published.
+
+        Parameters
+        ----------
+        event_type:
+            The event to listen for.
+        callback:
+            A callable with signature ``(event_type, data) -> None``.
+        """
+        with self._lock:
+            if callback not in self._subscribers[event_type]:
+                self._subscribers[event_type].append(callback)
+
+    def unsubscribe(self, event_type: EventType, callback: Callback) -> None:
+        """Remove a previously-registered callback."""
+        with self._lock:
+            try:
+                self._subscribers[event_type].remove(callback)
+            except ValueError:
+                pass
+
+    def publish(self, event_type: EventType, data: Any = None) -> None:
+        """Emit an event, invoking all registered callbacks synchronously.
+
+        Exceptions raised by individual callbacks are logged and swallowed so
+        that one faulty subscriber cannot break the pipeline.
+
+        Parameters
+        ----------
+        event_type:
+            The event being emitted.
+        data:
+            Arbitrary payload — typically a dataclass or dict.
+        """
+        with self._lock:
+            callbacks = list(self._subscribers[event_type])
+
+        for cb in callbacks:
+            try:
+                cb(event_type, data)
+            except Exception:
+                logger.exception(
+                    "Subscriber %r raised an exception for event %s",
+                    cb,
+                    event_type.name,
+                )
+
+    def clear(self, event_type: EventType | None = None) -> None:
+        """Remove all subscribers for *event_type*, or all subscribers if ``None``."""
+        with self._lock:
+            if event_type is None:
+                for et in EventType:
+                    self._subscribers[et].clear()
+            else:
+                self._subscribers[event_type].clear()
+
+
+# ---------------------------------------------------------------------------
+# Module-level singleton
+# ---------------------------------------------------------------------------
+event_bus = EventBus()