Service Communication Patterns in .NET Core and Azure

This article is part of the Comprehensive Guide to Microservices Architecture in .NET Core, Cloud and Azure series. Asynchronous Messaging with Azure Service Bus Azure Service Bus provides enterprise-grade messaging infrastructure with advanced features for reliable message delivery, ordering guarantees, and complex routing scenarios. Service Bus vs Azure Queue Storage Azure Service Bus offers enterprise messaging capabilities including: Topics and subscriptions for pub/sub patterns Message sessions for ordered processing Transaction support across operations Dead-letter queues for failed messages Messages up to 100MB (premium tier) Advanced routing with filters and actions Azure Queue Storage provides: Simple FIFO queue operations Lower cost for basic scenarios Messages up to 64KB Best for simple point-to-point messaging When to Choose Service Bus Use Azure Service Bus when you need: Publish-subscribe patterns with multiple subscribers Guaranteed message ordering with sessions Transactional message processing Message size beyond 64KB Advanced routing and filtering Integration with hybrid or on-premises systems Implementation with .NET 9 .NET 9 introduces improved performance and simplified APIs for working with Azure Service Bus: // Producer using .NET 9 with improved performance public class OrderCreatedPublisher { private readonly ServiceBusSender _sender ; public OrderCreatedPublisher ( ServiceBusClient client ) { _sender = client . CreateSender ( "order-events" ); } public async Task PublishOrderCreatedAsync ( Order order , CancellationToken cancellationToken = default ) { var message = new ServiceBusMessage ( JsonSerializer . Serialize ( order )) { MessageId = order . OrderId . ToString (), Subject = "OrderCreated" , ContentType = "application/json" , // .NET 9: Better support for distributed tracing ApplicationProperties = { [ "CorrelationId" ] = Activity . Current ?. Id ?? Guid . NewGuid (). ToString (), [ "OrderDate" ] = order . CreatedAt . ToString ( "O" )