update

Signed-off-by: William Fu-Hinthorn <13333726+hinthornw@users.noreply.github.com>

docs/docs/how-tos/persistence_postgres.ipynb

@@ -156,6 +156,29 @@
     "Async connections allow non-blocking database operations. This means other parts of your application can continue running while waiting for database operations to complete. It's particularly useful in high-concurrency scenarios or when dealing with I/O-bound operations."
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "2d8d6c9a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "DB_URI = \"postgresql://postgres:postgres@localhost:5442/postgres?sslmode=disable\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "351b4251",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "connection_kwargs = {\n",
+    "    \"autocommit\": True,\n",
+    "    \"prepare_threshold\": 0,\n",
+    "}"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "8e1dd27d",
@@ -244,11 +267,14 @@
     "import contextlib\n",
     "\n",
     "from starlette.applications import Starlette\n",
+    "from starlette.requests import Request\n",
+    "from starlette.responses import Response\n",
+    "from starlette.routing import Route\n",
+    "from psycopg_pool import AsyncConnectionPool\n",
+    "from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver\n",
     "\n",
-    "checkpointer = None\n",
     "@contextlib.asynccontextmanager\n",
     "async def lifespan(app):\n",
-    "    global checkpointer\n",
     "    async with AsyncConnectionPool(\n",
     "        # Example configuration\n",
     "        conninfo=DB_URI,\n",
@@ -259,34 +285,25 @@
     "\n",
     "        # NOTE: you need to call .setup() the first time you're using your checkpointer\n",
     "        await checkpointer.setup()\n",
-    "        yield\n",
+    "        yield {\"checkpointer\": checkpointer}\n",
     "\n",
     "\n",
     "graph = create_react_agent(model, tools=tools, checkpointer=checkpointer)\n",
     "\n",
-    "async def my_route(request):\n",
+    "async def my_route(request: Request):\n",
+    "    checkpointer = request.state.checkpointer\n",
     "    agent = graph.copy({\"checkpointer\": checkpointer})\n",
     "    await agent.ainvoke(request)\n",
     "    return Response(...)\n",
     "\n",
     "routes = [\n",
-    "    ...\n",
+    "    Route(\"/\", my_route),\n",
     "]\n",
     "\n",
     "app = Starlette(routes=routes, lifespan=lifespan)\n",
     "```"
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "876c5e02",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "https://www.starlette.io/lifespan/"
-   ]
-  },
   {
    "cell_type": "markdown",
    "id": "6e53287e",
@@ -394,29 +411,6 @@
     "Synchronous connections execute operations in a blocking manner, meaning each operation waits for completion before moving to the next one. The `DB_URI` is the database connection URI, with the protocol used for connecting to a PostgreSQL database, authentication, and host where database is running. The connection_kwargs dictionary defines additional parameters for the database connection."
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": 2,
-   "id": "2b9d13b1-9d72-48a0-b63a-adc062c06c29",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "DB_URI = \"postgresql://postgres:postgres@localhost:5442/postgres?sslmode=disable\""
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 3,
-   "id": "3fe36f67-073a-4fd7-a8f8-da196dd46a0d",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "connection_kwargs = {\n",
-    "    \"autocommit\": True,\n",
-    "    \"prepare_threshold\": 0,\n",
-    "}"
-   ]
-  },
   {
    "cell_type": "markdown",
    "id": "e39fc712-9e1c-4831-9077-dd07b0c13594",