caching queries to live and trails

main.py

@@ -31,6 +31,52 @@ from db_async import (
     init_db_async
 )
 import asyncio
+# In-memory caches for REST endpoints
+_cached_live: dict = {"players": []}
+_cached_trails: dict = {"trails": []}
+_cache_task: asyncio.Task | None = None
+
+async def _refresh_cache_loop() -> None:
+    """Background task: refresh `/live` and `/trails` caches every 5 seconds."""
+    while True:
+        try:
+            # Recompute live players (last 30s)
+            cutoff = datetime.now(timezone.utc) - ACTIVE_WINDOW
+            sql_live = """
+                SELECT sub.*,
+                       COALESCE(rs.total_rares, 0)      AS total_rares,
+                       COALESCE(rss.session_rares, 0)  AS session_rares
+                FROM (
+                    SELECT DISTINCT ON (character_name) *
+                    FROM telemetry_events
+                    WHERE timestamp > :cutoff
+                    ORDER BY character_name, timestamp DESC
+                ) sub
+                LEFT JOIN rare_stats rs
+                  ON sub.character_name = rs.character_name
+                LEFT JOIN rare_stats_sessions rss
+                  ON sub.character_name = rss.character_name
+                 AND sub.session_id    = rss.session_id
+            """
+            rows = await database.fetch_all(sql_live, {"cutoff": cutoff})
+            _cached_live["players"] = [dict(r) for r in rows]
+            # Recompute trails (last 600s)
+            cutoff2 = datetime.utcnow().replace(tzinfo=timezone.utc) - timedelta(seconds=600)
+            sql_trail = """
+                SELECT timestamp, character_name, ew, ns, z
+                FROM telemetry_events
+                WHERE timestamp >= :cutoff
+                ORDER BY character_name, timestamp
+            """
+            rows2 = await database.fetch_all(sql_trail, {"cutoff": cutoff2})
+            _cached_trails["trails"] = [
+                {"timestamp": r["timestamp"], "character_name": r["character_name"],
+                 "ew": r["ew"], "ns": r["ns"], "z": r["z"]}
+                for r in rows2
+            ]
+        except Exception as e:
+            print(f"[CACHE] refresh error: {e}")
+        await asyncio.sleep(5)
 
 # ------------------------------------------------------------------
 app = FastAPI()
@@ -121,13 +167,23 @@ async def on_startup():
                 await asyncio.sleep(5)
     else:
         raise RuntimeError(f"Could not connect to database after {max_attempts} attempts")
-    
+    # Start background cache refresh (live & trails)
+    global _cache_task
+    _cache_task = asyncio.create_task(_refresh_cache_loop())
 @app.on_event("shutdown")
 async def on_shutdown():
     """Event handler triggered when application is shutting down.
 
     Ensures the database connection is closed cleanly.
     """
+    # Stop cache refresh task
+    global _cache_task
+    if _cache_task:
+        _cache_task.cancel()
+        try:
+            await _cache_task
+        except asyncio.CancelledError:
+            pass
     await database.disconnect()
 
 
@@ -141,31 +197,8 @@ def debug():
 @app.get("/live", response_model=dict)
 @app.get("/live/", response_model=dict)
 async def get_live_players():
-    """Return recent live telemetry per character (last 30 seconds)."""
-    cutoff = datetime.now(timezone.utc) - ACTIVE_WINDOW
-    # Build SQL to select the most recent telemetry entry per character:
-    #   - Use DISTINCT ON (character_name) to get latest row for each player
-    #   - Join rare_stats for cumulative counts and rare_stats_sessions for session-specific counts
-    sql = """
-        SELECT sub.*,
-               COALESCE(rs.total_rares, 0)      AS total_rares,
-               COALESCE(rss.session_rares, 0)  AS session_rares
-        FROM (
-            SELECT DISTINCT ON (character_name) *
-            FROM telemetry_events
-            WHERE timestamp > :cutoff
-            ORDER BY character_name, timestamp DESC
-        ) sub
-        LEFT JOIN rare_stats rs
-          ON sub.character_name = rs.character_name
-        LEFT JOIN rare_stats_sessions rss
-          ON sub.character_name = rss.character_name
-         AND sub.session_id    = rss.session_id
-    """
-    rows = await database.fetch_all(sql, {"cutoff": cutoff})
-    players = [dict(r) for r in rows]
-    # Ensure all types (e.g. datetime) are JSON serializable
-    return JSONResponse(content=jsonable_encoder({"players": players}))
+    """Return cached live telemetry per character."""
+    return JSONResponse(content=jsonable_encoder(_cached_live))
 
 
 
@@ -176,28 +209,8 @@ async def get_live_players():
 async def get_trails(
     seconds: int = Query(600, ge=0, description="Lookback window in seconds"),
 ):
-    """Return position snapshots (timestamp, character_name, ew, ns, z) for the past `seconds`."""
-    cutoff = datetime.utcnow().replace(tzinfo=timezone.utc) - timedelta(seconds=seconds)
-    # Query position snapshots for all characters since the cutoff time
-    sql = """
-        SELECT timestamp, character_name, ew, ns, z
-        FROM telemetry_events
-        WHERE timestamp >= :cutoff
-        ORDER BY character_name, timestamp
-    """
-    rows = await database.fetch_all(sql, {"cutoff": cutoff})
-    trails = [
-        {
-            "timestamp": r["timestamp"],
-            "character_name": r["character_name"],
-            "ew": r["ew"],
-            "ns": r["ns"],
-            "z": r["z"],
-        }
-        for r in rows
-    ]
-    # Ensure all types (e.g. datetime) are JSON serializable
-    return JSONResponse(content=jsonable_encoder({"trails": trails}))
+    """Return cached trails (updated every 5 seconds)."""
+    return JSONResponse(content=jsonable_encoder(_cached_trails))
 
 # --------------------  WebSocket endpoints -----------------------
 ## WebSocket connection tracking