Merge pull request #271701 from wmwxwa/patch-17

Functions+Cosmos integration & Cosmos async SDK+singleton functions-r…

Author: prmerger-automator[bot]

articles/azure-functions/functions-reference-python.md

@@ -214,9 +214,15 @@ When you deploy your project to a function app in Azure, the entire contents of
 
 ## Connect to a database
 
-[Azure Cosmos DB](../cosmos-db/introduction.md) is a fully managed NoSQL, relational, and vector database for modern app development including AI, digital commerce, Internet of Things, booking management, and other types of solutions. It offers single-digit millisecond response times, automatic and instant scalability, and guaranteed speed at any scale. Its various APIs can accommodate all your operational data models, including relational, document, vector, key-value, graph, and table.
+Azure Functions integrates well with [Azure Cosmos DB](../cosmos-db/introduction.md) for many [use cases](../cosmos-db/use-cases.md), including IoT, ecommerce, gaming, etc.
 
-To connect to Cosmos DB, first [create an account, database, and container](../cosmos-db/nosql/quickstart-portal.md). Then you may connect Functions to Cosmos DB using [trigger and bindings](functions-bindings-cosmosdb-v2.md), like this [example](functions-add-output-binding-cosmos-db-vs-code.md). You may also use the Python library for Cosmos DB, like so:
+For example, for [event sourcing](https://learn.microsoft.com/azure/architecture/patterns/event-sourcing), the two services are integrated to power event-driven architectures using Azure Cosmos DB's [change feed](../cosmos-db/change-feed.md) functionality. The change feed provides downstream microservices the ability to reliably and incrementally read inserts and updates (for example, order events). This functionality can be leveraged to provide a persistent event store as a message broker for state-changing events and drive order processing workflow between many microservices (which can be implemented as [serverless Azure Functions](https://azure.com/serverless)).
+
+:::image type="content" source="../cosmos-db/media/use-cases/event-sourcing.png" alt-text="Azure Cosmos DB ordering pipeline reference architecture" border="false":::
+
+To connect to Cosmos DB, first [create an account, database, and container](../cosmos-db/nosql/quickstart-portal.md). Then you may connect Functions to Cosmos DB using [trigger and bindings](functions-bindings-cosmosdb-v2.md), like this [example](functions-add-output-binding-cosmos-db-vs-code.md).
+
+To implement more complex app logic, you may also use the Python library for Cosmos DB. An aynchronous I/O implementation looks like this:
 
 ```python
 pip install azure-cosmos
@@ -237,9 +243,11 @@ partition_key = "/partition_key"
 # Set the total throughput (RU/s) for the database and container
 database_throughput = 1000
 
+# Singleton CosmosClient instance
+client = CosmosClient(endpoint, credential=key)
+
 # Helper function to get or create database and container
 async def get_or_create_container(client, database_id, container_id, partition_key):
-
     database = await client.create_database_if_not_exists(id=database_id)
     print(f'Database "{database_id}" created or retrieved successfully.')
 
@@ -249,28 +257,37 @@ async def get_or_create_container(client, database_id, container_id, partition_k
     return container
 
 async def create_products():
-    async with CosmosClient(endpoint, credential=key) as client:
-        container = await get_or_create_container(client, database_id, container_id, partition_key)
-        for i in range(10):
-            await container.upsert_item({
-                'id': f'item{i}',
-                'productName': 'Widget',
-                'productModel': f'Model {i}'
-            })
+    container = await get_or_create_container(client, database_id, container_id, partition_key)
+    for i in range(10):
+        await container.upsert_item({
+            'id': f'item{i}',
+            'productName': 'Widget',
+            'productModel': f'Model {i}'
+        })
 
 async def get_products():
     items = []
-    async with CosmosClient(endpoint, credential=key) as client:
-        container = await get_or_create_container(client, database_id, container_id, partition_key)
-        async for item in container.read_all_items():
-            items.append(item)
+    container = await get_or_create_container(client, database_id, container_id, partition_key)
+    async for item in container.read_all_items():
+        items.append(item)
     return items
- 
+
+async def query_products(product_name):
+    container = await get_or_create_container(client, database_id, container_id, partition_key)
+    query = f"SELECT * FROM c WHERE c.productName = '{product_name}'"
+    items = []
+    async for item in container.query_items(query=query, enable_cross_partition_query=True):
+        items.append(item)
+    return items
+
 async def main():
     await create_products()
-    products = await get_products()
-    print(products)
- 
+    all_products = await get_products()
+    print('All Products:', all_products)
+
+    queried_products = await query_products('Widget')
+    print('Queried Products:', queried_products)
+
 if __name__ == "__main__":
     asyncio.run(main())
 ```