Functions with Cosmos DB integration in Azure - Mini Project: Build & Apply

Functions with Cosmos DB integration

📖 Scenario: You are building a simple Azure Function that interacts with Cosmos DB to store and retrieve user data. This is a common pattern in cloud applications where serverless functions handle data operations.

🎯 Goal: Create an Azure Function that connects to a Cosmos DB container, inserts a user document, and queries users by a specific property.

📋 What You'll Learn

Create a Cosmos DB client connection string variable

Define a function to insert a user document into Cosmos DB

Define a function to query users by their city

Configure the Azure Function to use the Cosmos DB client

💡 Why This Matters

🌍 Real World

Serverless functions often need to store and retrieve data from databases like Cosmos DB. This project shows how to connect and perform basic operations.

💼 Career

Understanding how to integrate Azure Functions with Cosmos DB is a key skill for cloud developers working on scalable, event-driven applications.

1

Create Cosmos DB connection string variable

Create a variable called cosmos_connection_string and set it to the exact string "AccountEndpoint=https://mycosmos.documents.azure.com:443/;AccountKey=ABC123==;".

Azure

# Your code here

Need a hint?

Use a simple string assignment to create the connection string variable.

2

Create Cosmos DB client variable

Using the cosmos_connection_string variable, create a Cosmos DB client variable called client by calling CosmosClient(cosmos_connection_string). Assume CosmosClient is already imported.

Azure

cosmos_connection_string = "AccountEndpoint=https://mycosmos.documents.azure.com:443/;AccountKey=ABC123==;"
# Your code here

Need a hint?

Instantiate the CosmosClient using the connection string variable with from_connection_string method.

3

Define function to insert a user document

Define a function called insert_user that takes parameters database_name, container_name, and user_data. Inside the function, get the container from client using client.get_database_client(database_name).get_container_client(container_name). Then call container.create_item(user_data) to insert the document.

Azure

cosmos_connection_string = "AccountEndpoint=https://mycosmos.documents.azure.com:443/;AccountKey=ABC123==;"
client = CosmosClient.from_connection_string(cosmos_connection_string)

# Your code here

Need a hint?

Define the function with the exact name and parameters. Use the client to get the container and call create_item.

4

Define function to query users by city

Define a function called query_users_by_city that takes parameters database_name, container_name, and city. Inside the function, get the container from client as before. Then create a SQL query string "SELECT * FROM c WHERE c.city = @city". Use container.query_items with the query and parameters [{"name": "@city", "value": city}], and set enable_cross_partition_query=True. Return the list of results.

Azure

cosmos_connection_string = "AccountEndpoint=https://mycosmos.documents.azure.com:443/;AccountKey=ABC123==;"
client = CosmosClient.from_connection_string(cosmos_connection_string)

def insert_user(database_name, container_name, user_data):
    container = client.get_database_client(database_name).get_container_client(container_name)
    container.create_item(user_data)

# Your code here

Need a hint?

Define the function with the exact name and parameters. Use a parameterized SQL query and return the results as a list.