update based on uuf

Signed-off-by: Hannah Hunter <[email protected]>

Author: hhunter-ms

articles/azure-functions/durable/durable-functions-singletons.md

@@ -69,6 +69,9 @@ public static async Task<HttpResponseData> RunSingle(
 
 # [JavaScript](#tab/javascript)
 
+> [!NOTE]
+> This JavaScript example uses the Node.js programming model v3, which uses *function.json*. If you're using the Node.js programming model v4, use the v4 code-first pattern instead.
+
 **function.json**
 
 ```json
@@ -130,57 +133,37 @@ module.exports = async function(context, req) {
 
 # [Python](#tab/python)
 
-**function.json**
-
-```json
-{
-  "bindings": [
-    {
-      "authLevel": "function",
-      "name": "req",
-      "type": "httpTrigger",
-      "direction": "in",
-      "route": "orchestrators/{functionName}/{instanceId}",
-      "methods": ["post"]
-    },
-    {
-      "name": "starter",
-      "type": "orchestrationClient",
-      "direction": "in"
-    },
-    {
-      "name": "$return",
-      "type": "http",
-      "direction": "out"
-    }
-  ]
-}
-```
-
-**__init__.py**
+**function_app.py**
 
 ```python
 import logging
 import azure.functions as func
 import azure.durable_functions as df
 
-async def main(req: func.HttpRequest, starter: str) -> func.HttpResponse:
-    client = df.DurableOrchestrationClient(starter)
-    instance_id = req.route_params['instanceId']
-    function_name = req.route_params['functionName']
+app = df.DFApp(http_auth_level=func.AuthLevel.FUNCTION)
+
+@app.route(route="orchestrators/{functionName}/{instanceId}", methods=["POST"])
+@app.durable_client_input(client_name="client")
+async def http_start_single(req: func.HttpRequest, client):
+        instance_id = req.route_params["instanceId"]
+        function_name = req.route_params["functionName"]
 
     existing_instance = await client.get_status(instance_id)
 
-    if existing_instance.runtime_status in [df.OrchestrationRuntimeStatus.Completed, df.OrchestrationRuntimeStatus.Failed, df.OrchestrationRuntimeStatus.Terminated, None]:
+        if not existing_instance or existing_instance.runtime_status in [
+                df.OrchestrationRuntimeStatus.Completed,
+                df.OrchestrationRuntimeStatus.Failed,
+                df.OrchestrationRuntimeStatus.Terminated,
+        ]:
         event_data = req.get_body()
-        instance_id = await client.start_new(function_name, instance_id, event_data)
+                instance_id = await client.start_new(function_name, instance_id, event_data)
         logging.info(f"Started orchestration with ID = '{instance_id}'.")
         return client.create_check_status_response(req, instance_id)
-    else:
-        return {
-            'status': 409,
-            'body': f"An instance with ID '${existing_instance.instance_id}' already exists"
-        }
+
+        return func.HttpResponse(
+                body=f"An instance with ID '{instance_id}' already exists.",
+                status_code=409,
+        )
 
 ```