closed TG-1; git was inited;

src/ais_hub/publish/udp_events.py

@@ -0,0 +1,73 @@
+"""UDP JSON event publisher on ``127.0.0.1:7001`` (configurable).
+
+Contract: one serialized ``Event`` per UDP datagram. Events larger than
+``max_datagram_bytes`` are dropped and counted in
+``stats.udp_events_oversize`` (no fragmentation).
+"""
+
+from __future__ import annotations
+
+import asyncio
+import json
+import logging
+from typing import Any
+
+from ..config import UdpEventsCfg
+from ..core.bus import EventBus
+from ..core.models import Event
+from ..core.stats import Stats
+
+log = logging.getLogger(__name__)
+
+
+class UdpEventsPublisher:
+    def __init__(self, cfg: UdpEventsCfg, bus: EventBus, stats: Stats) -> None:
+        self._cfg = cfg
+        self._bus = bus
+        self._stats = stats
+        self._transport: asyncio.DatagramTransport | None = None
+        self._sub: asyncio.Queue[Event] | None = None
+
+    async def run(self) -> None:
+        loop = asyncio.get_running_loop()
+        # Ephemeral sender socket; we only *send* to a fixed target.
+        transport, _ = await loop.create_datagram_endpoint(
+            lambda: asyncio.DatagramProtocol(),
+            remote_addr=(self._cfg.host, self._cfg.port),
+        )
+        self._transport = transport
+        self._sub = self._bus.subscribe(maxsize=1024)
+        log.info("udp_events publisher -> %s:%d", self._cfg.host, self._cfg.port)
+        try:
+            while True:
+                ev = await self._sub.get()
+                self._send(ev)
+        except asyncio.CancelledError:
+            raise
+        finally:
+            if self._sub is not None:
+                self._bus.unsubscribe(self._sub)
+                self._sub = None
+            if self._transport is not None:
+                self._transport.close()
+                self._transport = None
+
+    def _send(self, ev: Event) -> None:
+        try:
+            blob = json.dumps(ev.to_dict(), ensure_ascii=False, separators=(",", ":")).encode("utf-8")
+        except Exception:
+            self._stats.incr("udp_events_serialize_errors")
+            return
+        if len(blob) > self._cfg.max_datagram_bytes:
+            self._stats.incr("udp_events_oversize")
+            return
+        try:
+            assert self._transport is not None
+            self._transport.sendto(blob)
+            self._stats.incr("udp_events_sent")
+        except Exception:
+            self._stats.incr("udp_events_send_errors")
+            log.debug("udp_events send failed", exc_info=True)
+
+
+__all__ = ["UdpEventsPublisher"]