Implement session consistency by using session tokens

Session consistency is an essential aspect when designing and implementing native applications using Microsoft Azure Cosmos DB. By using session tokens, you can ensure that your application maintains data consistency and provides a seamless user experience. In this article, we will explore how to implement session consistency using session tokens in Azure Cosmos DB.

Establishing a Session

To begin, the first step is to establish a session with Azure Cosmos DB. This can be achieved by using any of the supported SDKs, such as .NET, Java, or Node.js. Let’s take an example of a .NET application. The code snippet below shows how to establish a session using the .NET SDK:

using Microsoft.Azure.Cosmos;
// Other necessary using statements

// Create a new session
using (ResponseMessage response = await container.CreateTransactionalBatch(new PartitionKey("partition-key"))
.CreateItemAsync

In the above code, we create a CosmosClient and retrieve the desired container using the provided connection string and IDs. We then create a new session by using the CreateTransactionalBatch method. This ensures that all subsequent operations performed within this batch are associated with the same session.

Maintaining Session Consistency

Once we have a session token, we can use it in subsequent read and write operations to maintain session consistency. Let’s consider a scenario where we want to read an item from the container. The following code snippet demonstrates how to use the session token for consistent reads:

using (ResponseMessage response = await container.ReadItemAsync(itemId, partitionKey,
new ItemRequestOptions { SessionToken = sessionToken }))
{
dynamic item = response.Resource;
// Perform further actions on the retrieved item
}


In the code above, we utilize the ReadItemAsync method with the ItemRequestOptions object, specifying the session token acquired earlier. This ensures that the read operation is consistent within the same session.

Similarly, session consistency can be enforced during write operations. The code snippet below demonstrates how to use the session token during an item update:

using (ResponseMessage response = await container.ReplaceItemAsync

In the code above, we utilize the ReplaceItemAsync method and include the session token in the ItemRequestOptions. This guarantees that the update operation is performed within the same session and maintains session consistency.

Conclusion

By implementing session consistency using session tokens in Azure Cosmos DB, you can ensure that your native applications maintain data integrity and provide a reliable user experience. Remember to establish a session at the beginning of the client interaction and utilize the session token in subsequent read and write operations.

In summary, the session consistency feature in Azure Cosmos DB allows you to maintain data consistency within a single client session. By using session tokens, you can implement session consistency in your native applications. This ensures that your application provides reliable and consistent data access to users.