Initial commit

core/event_store.py

@@ -0,0 +1,108 @@
+from collections import deque
+from typing import Optional, Any, Callable, Iterator
+
+from core.events import Event, bus
+
+
+class EventStore:
+    def __init__(self, max_size: int = 10_000):
+        self.buffer: deque[Event] = deque(maxlen=max_size)
+        self._cursor: int = 0
+
+        bus.subscribe(self._capture)
+
+    # =========================
+    # CAPTURE
+    # =========================
+
+    def _capture(self, event: Event):
+        event.meta["cursor"] = self._cursor
+
+        self.buffer.append(event)
+        self._cursor += 1
+
+    # =========================
+    # QUERY
+    # =========================
+
+    def query(
+        self,
+        source: Optional[str] = None,
+        level: Optional[str] = None,
+        name: Optional[str] = None,
+        start_cursor: Optional[int] = None,
+        end_cursor: Optional[int] = None,
+    ) -> list[Event]:
+
+        events = list(self.buffer)
+
+        if source is not None:
+            events = [e for e in events if e.source == source]
+
+        if level is not None:
+            events = [e for e in events if e.level == level]
+
+        if name is not None:
+            events = [e for e in events if e.name == name]
+
+        def cursor_of(e: Event) -> int:
+            return e.meta.get("cursor", -1)
+
+        if start_cursor is not None:
+            events = [e for e in events if cursor_of(e) >= start_cursor]
+
+        if end_cursor is not None:
+            events = [e for e in events if cursor_of(e) <= end_cursor]
+
+        return events
+
+    # =========================
+    # PAGINATION
+    # =========================
+
+    def page(self, cursor: int = 0, limit: int = 100) -> dict[str, Any]:
+        events = list(self.buffer)
+        sliced = events[cursor:cursor + limit]
+
+        return {
+            "cursor": cursor,
+            "next_cursor": cursor + len(sliced),
+            "count": len(sliced),
+            "events": sliced
+        }
+
+    # =========================
+    # REPLAY
+    # =========================
+
+    def replay(
+        self,
+        source: Optional[str] = None,
+        level: Optional[str] = None,
+        name: Optional[str] = None,
+        handler: Optional[Callable[[Event], Any]] = None,
+    ):
+        for event in self.query(source, level, name):
+            if handler:
+                handler(event)
+            else:
+                bus.emit(event)
+
+    # =========================
+    # REVERSE DEBUG
+    # =========================
+
+    def replay_reverse(self, handler: Callable[[Event], Any]):
+        for event in reversed(self.buffer):
+            handler(event)
+
+    # =========================
+    # STREAM TAIL
+    # =========================
+
+    def tail(self, last_n: int = 50) -> Iterator[Event]:
+        yield from list(self.buffer)[-last_n:]
+
+
+# singleton
+event_store = EventStore()