Azure Service Bus

1. What is Azure Service Bus?

• Decoupling application components for scalability and resilience.

• Handling high-throughput message workflows.

• Reliable delivery with features like message sessions, dead-letter queues, duplicate detection.

• Advanced routing with topics and subscription filters.

2. Core Concepts and Components

3. Azure Service Bus Messaging Models

• Queue-based Messaging:
Point-to-point communication where sender posts messages and a single receiver consumes them.

• Topic-based Publish-Subscribe:
A message sent to a topic can be delivered to multiple independent subscriptions, each receiving a filtered set if desired.

4. Development and SDKs

Sample: Sending and Receiving Messages with .NET SDK (.NET 6+)

using Azure.Messaging.ServiceBus;

string connectionString = "<your_namespace_connection_string>";
string queueName = "myqueue";

// Create client and sender
await using var client = new ServiceBusClient(connectionString);
ServiceBusSender sender = client.CreateSender(queueName);

// Send a message
ServiceBusMessage message = new ServiceBusMessage("Hello Azure Service Bus!");
await sender.SendMessageAsync(message);

// Create a processor for receiving messages
ServiceBusProcessor processor = client.CreateProcessor(queueName, new ServiceBusProcessorOptions());

processor.ProcessMessageAsync += async args =>
{
    string body = args.Message.Body.ToString();
    Console.WriteLine($"Received: {body}");
    
    // Complete the message so that it's not received again
    await args.CompleteMessageAsync(args.Message);
};

processor.ProcessErrorAsync += async args =>
{
    Console.WriteLine(args.Exception.ToString());
};

await processor.StartProcessingAsync();

// Wait for some time to receive messages
await Task.Delay(10000);

// Stop processing
await processor.StopProcessingAsync();

5. Pricing Model

6. Scalability

• Service Bus namespaces can scale automatically.

• Premium tier provides reserved throughput units supporting predictable performance and scaling.

• Partitioned queues and topics enable data and load partitioning internally.

• Auto-forwarding allows chaining and load distribution.

7. Security and Identity Management (IAM)

8. Deployment and Configuration

How to Create and Manage Service Bus Resources

• Azure Portal UI

• Azure CLI

• Azure PowerShell

• ARM templates / Bicep

• SDKs / REST APIs

Example CLI command to create a Service Bus Namespace and Queue

# Create resource group
az group create --name MyResourceGroup --location eastus

# Create Service Bus namespace
az servicebus namespace create --resource-group MyResourceGroup --name MyNamespace --location eastus --sku Standard

# Create a queue
az servicebus queue create --resource-group MyResourceGroup --namespace-name MyNamespace --name myqueue

9. Advanced Features and Patterns

• Message Sessions: Enable FIFO message handling and correlation of message sequences.

• Dead Letter Queues (DLQ): Automatically store undeliverable or expired messages for inspection.

• Scheduled Messages: Send messages to be available at a specific future time.

• Message Deferral: Temporarily skip processing a message, retaining it for later retrieval.

• Transactions: Group multiple message operations atomically.

• Auto-forwarding: Chain queues and subscriptions to create message routing pipelines.

• Duplicate Detection: Prevent processing of duplicate messages.

• Filters and Actions on Subscriptions: Only receive messages matching certain conditions; modify message metadata.

• Geo-Disaster Recovery: Configure namespace failover across regions.

• Auto-delete on Idle: Automatically cleans up unused entities.

10. Common Use Cases

• Decoupling microservices with reliable messaging.

• Load leveling for traffic bursts.

• Event-driven architectures.

• Workflow and Order processing systems.

• IoT and telemetry ingestion pipelines.

• Hybrid cloud scenarios connecting on-premises and cloud systems.

11. Best Practices

• Use Sessions for ordered message processing.

• Implement Dead Lettering and monitor DLQs for failures.

• Leverage Duplicate Detection to avoid repeated message processing.

• Use Auto-forwarding to decouple and chain message workflows.

• Secure access using Azure AD and Managed Identities rather than connection strings where possible.

• Monitor using Azure Monitor and Azure Metrics.

12. Monitoring and Diagnostics

• Azure Monitor metrics for throughput, queue length, dead-letter messages.

• Diagnostic logs for operational insights.

• Alerts to proactively manage system health.

• Use Service Bus Explorer tools for operational management and troubleshooting.

13. Summary Table for Azure Service Bus

14. Service bus Queue vs Storage Queue

15. Service bus topics vs Event Grid Topic

FAQ

• Queue: A FIFO message store where messages are received and processed by a single consumer (point-to-point messaging).

• Topic: Supports publish-subscribe pattern where messages sent to a topic can be received by multiple independent subscriptions.

• Subscription: Attached to a topic; acts as a virtual queue receiving filtered subsets of topic messages.

Intermediate Questions and Answers

• Basic/Standard: Shared infrastructure with core messaging features, charged by number of operations and message size; suitable for most workloads.

• Premium: Dedicated resources (Messaging Units) with guaranteed throughput, advanced features like geo-disaster recovery, VNet, and predictable performance.

Advanced & Tricky Questions and Answers

Scenario-Based Questions