Ensure only 1 connection during lambda execution

space2stats_api/src/space2stats/api/db.py

@@ -1,6 +1,6 @@
 """Database connection handling."""
 
-from typing import TYPE_CHECKING, Any, Dict, Optional
+from typing import TYPE_CHECKING
 
 from fastapi import FastAPI
 from psycopg_pool import ConnectionPool
@@ -11,7 +11,7 @@
 
 async def connect_to_db(
     app: FastAPI,
-    pool_kwargs: Optional[Dict[str, Any]] = None,
+    **overrides,
 ) -> None:
     """Connect to Database."""
     settings: "Settings" = app.extra.get("settings")
@@ -20,18 +20,19 @@ async def connect_to_db(
             "Settings not found in app.extra. FastAPI app must be initialized with "
             "settings provided as a keyword argument."
         )
-    pool_kwargs = pool_kwargs or {}
-
-    app.state.pool = ConnectionPool(
-        conninfo=settings.DB_CONNECTION_STRING,
-        min_size=settings.DB_MIN_CONN_SIZE,
-        max_size=settings.DB_MAX_CONN_SIZE,
-        max_waiting=settings.DB_MAX_QUERIES,
-        max_idle=settings.DB_MAX_IDLE,
-        num_workers=settings.DB_NUM_WORKERS,
-        kwargs=pool_kwargs,
-        open=True,
-    )
+
+    pool_kwargs = {
+        "conninfo": settings.DB_CONNECTION_STRING,
+        "min_size": settings.DB_MIN_CONN_SIZE,
+        "max_size": settings.DB_MAX_CONN_SIZE,
+        "max_waiting": settings.DB_MAX_QUERIES,
+        "max_idle": settings.DB_MAX_IDLE,
+        "num_workers": settings.DB_NUM_WORKERS,
+        "open": True,
+        **overrides,
+    }
+
+    app.state.pool = ConnectionPool(**pool_kwargs)
 
     # Make sure the pool is ready
     # ref: https://www.psycopg.org/psycopg3/docs/advanced/pool.html#pool-startup-check

space2stats_api/src/space2stats/api/handler.py

@@ -12,7 +12,7 @@
 @app.on_event("startup")
 async def startup_event() -> None:
     """Connect to database on startup."""
-    await connect_to_db(app)
+    await connect_to_db(app, max_size=1)
 
 
 handler = Mangum(app, lifespan="off")