Add websocket event stream for sim updates.

As a proof of concept this only covers the flight positions.

game/server/__init__.py

@@ -1,2 +1,3 @@
 from .dependencies import GameContext
+from .eventstream import EventStream
 from .server import Server

game/server/app.py

@@ -1,6 +1,7 @@
 from fastapi import FastAPI
 
-from . import debuggeometries
+from . import debuggeometries, eventstream
 
 app = FastAPI()
 app.include_router(debuggeometries.router)
+app.include_router(eventstream.router)

game/server/eventstream/__init__.py

@@ -0,0 +1,2 @@
+from .eventstream import EventStream
+from .routes import router

game/server/eventstream/eventstream.py

@@ -0,0 +1,29 @@
+from asyncio import Queue
+
+from game.sim.gameupdateevents import GameUpdateEvents
+
+
+class EventStream:
+    _queue: Queue[GameUpdateEvents] = Queue()
+
+    @classmethod
+    def drain(cls) -> None:
+        while not cls._queue.empty():
+            cls._queue.get_nowait()
+            cls._queue.task_done()
+
+    @classmethod
+    async def put(cls, events: GameUpdateEvents) -> None:
+        await cls._queue.put(events)
+
+    @classmethod
+    def put_nowait(cls, events: GameUpdateEvents) -> None:
+        # The queue has infinite size so this should never need to block anyway. If for
+        # some reason the queue is full this will throw QueueFull.
+        cls._queue.put_nowait(events)
+
+    @classmethod
+    async def get(cls) -> GameUpdateEvents:
+        events = await cls._queue.get()
+        cls._queue.task_done()
+        return events

game/server/eventstream/models.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+from uuid import UUID
+
+from pydantic import BaseModel
+
+from game.server.leaflet import LeafletLatLon
+
+if TYPE_CHECKING:
+    from game import Game
+    from game.sim.gameupdateevents import GameUpdateEvents
+
+
+class GameUpdateEventsJs(BaseModel):
+    updated_flights: dict[UUID, LeafletLatLon]
+
+    @classmethod
+    def from_events(cls, events: GameUpdateEvents, game: Game) -> GameUpdateEventsJs:
+        return GameUpdateEventsJs(
+            updated_flights={
+                f[0].id: game.theater.point_to_ll(f[1]).as_list()
+                for f in events.updated_flights
+            }
+        )

game/server/eventstream/routes.py

@@ -0,0 +1,21 @@
+from fastapi import APIRouter
+from fastapi.encoders import jsonable_encoder
+from starlette.websockets import WebSocket
+
+from .eventstream import EventStream
+from .models import GameUpdateEventsJs
+from .. import GameContext
+
+router = APIRouter()
+
+
+@router.websocket("/eventstream")
+async def event_stream(websocket: WebSocket) -> None:
+    await websocket.accept()
+    while True:
+        if not (events := await EventStream.get()).empty:
+            await websocket.send_json(
+                jsonable_encoder(
+                    GameUpdateEventsJs.from_events(events, GameContext.get())
+                )
+            )