Azure Service Bus Configuration

General

Azure Service Bus (ASB) is a fully managed enterprise message broker and is well documented Brighter handles the details of sending to or receiving from ASB. You may find it useful to understand the concepts of the ASB.

Connection

The connection to ASB id defined by an IServiceBusClientProvider, Brighter proviedes the following Implimentations

• ServiceBusChainedClientProvider: A client provider that allows you to specific a chain of TokenCredentials to authenticate with.

• ServiceBusConnectionStringClientProvider: A client provider that accepts a connection string (containg Authentication information)

• ServiceBusDefaultAzureClientProvider: A client provider that uses the Default Azure Credential to authenticate.

• ServiceBusManagedIdentityClientProvider: A client provider that uses Azure Managed Identity to authenticate.

• ServiceBusVisualStudioCredentialClientProvider: A client provider that uses Visual Studio Credential to authenticate.

In Brighter's implementation of the Messaging Gateway Publications and Subscriptions have their own Individual configuration.

Publication

No custom properties are supported for ASB

Basic Brighter configutarion publications is as follows

public void ConfigureServices(IServiceCollection services)
{
    services.AddBrighter(...)
        .UseExternalBus(
        new AzureServiceBusProducerRegistryFactory(
                asbConnection,
                new AzureServiceBusPublication[]
                {
                    new() { Topic = new RoutingKey("greeting.event") },
                    new() { Topic = new RoutingKey("greeting.addGreetingCommand") },
                    new() { Topic = new RoutingKey("greeting.Asyncevent") }
                }
            )
            .Create()
    )
}

For more on a Publication see the material on an External Bus in Basic Configuration.

Subscription

For more on a Subscription see the material on configuring Service Activator in Basic Configuration.

When

We support a number of ASB specific Subscription options:

• MaxDeliveryCount: The Maximum amount of times that a Message can be delivered before it is dead Lettered. This differs from requeue count as this is used by the transport in the event of lock expiry (in the event of process failure or processing taking too long) default: 5

• DeadLetteringOnMessageExpiration: Dead letter a message when it expires default: true

• LockDuration: How long message locks are held for default: true

• DefaultMessageTimeToLive: How long messages sit in the queue before they expire default: 1 minute

• SqlFilter: A Sql Filter to apply to the subscription see Topic Filters default: none

This is a typical Subscription configuration in a Consumer application:

private static void ConfigureBrighter(HostBuilderContext hostContext, IServiceCollection services)
{
    var subscriptions = new Subscription[]
    {
        new AzureServiceBusSubscription<GreetingAsyncEvent>(
            new SubscriptionName(GreetingEventAsyncMessageMapper.Topic),
            new ChannelName(subscriptionName),
            new RoutingKey(GreetingEventAsyncMessageMapper.Topic),
            timeoutInMilliseconds: 400,
            makeChannels: OnMissingChannel.Create,
            requeueCount: 3,
            isAsync: true,
            noOfPerformers: 2, unacceptableMessageLimit: 1),
        new AzureServiceBusSubscription<GreetingEvent>(
            new SubscriptionName(GreetingEventMessageMapper.Topic),
            new ChannelName(subscriptionName),
            new RoutingKey(GreetingEventMessageMapper.Topic),
            timeoutInMilliseconds: 400,
            makeChannels: OnMissingChannel.Create,
            requeueCount: 3,
            isAsync: false,
            noOfPerformers: 2),
        new AzureServiceBusSubscription<AddGreetingCommand>(
            new SubscriptionName(AddGreetingMessageMapper.Topic),
            new ChannelName(subscriptionName),
            new RoutingKey(AddGreetingMessageMapper.Topic),
            timeoutInMilliseconds: 400,
            makeChannels: OnMissingChannel.Create,
            requeueCount: 3,
            isAsync: true,
            noOfPerformers: 2)
    };

    var clientProvider = new ServiceBusVisualStudioCredentialClientProvider("my-awesome-asb.servicebus.windows.net");

    var asbConsumerFactory = new AzureServiceBusConsumerFactory(clientProvider);

    builder.Services.AddServiceActivator(options =>
    {
        options.Subscriptions = subscriptions;
        options.ChannelFactory = new AzureServiceBusChannelFactory(asbConsumerFactory);
        
    }

Complete Reject

We use ASB's Subscription to surscribe to a Topic on a namespace.

When we Complete a message, in response to a handler chain completing, we Complete the message on ASB using messageReceiver.CompleteMessageAsync. Note that we only Complete a message once we have completed running the chain and only if AckOnRead is set to false (as the messages is removed from the queue otherwise).

When we Dead Letter a message (see Handler Failure for more on failure) then we use messageReceiver.DeadLetterMessageAsync to delete the message, and move it to a DLQ.