DNV.Context.ServiceBus

The DNV.Context.ServiceBus package is a .Net library which provides some extension method based on Azure.Messaging.ServiceBus for sending and receiving messages with ambient context(IContextAccessor<>).

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Basic example

Send Message With Context

You can self define the context payload, ex

public class SampleContext
    {
        public string Name { get; set; }
        public string SampleData { get; set; }
    }

Before start sending the message, get the IContextAccessor<> at first, and then call the extension method SendMessageAsync<>(message, context) with the context. It will send the context within the message. The correlation id will be set into message.CorrelationId, and the detailed context will be set into the customized key(X-Ambient-Context-{typeof(T).Name}) inside the message property ApplicationProperties.

public class ExampleController : Controller
    {
        private readonly ILogger<HomeController> _logger;
        private readonly IContextAccessor<SampleContext> _contextAccessor;
        private readonly ServiceBusConfig _serviceBusConfig;

        public HomeController(ILogger<HomeController> logger, IContextAccessor<SampleContext> contextAccessor, IOptionsSnapshot<ServiceBusConfig> serviceBusOptions)
        {
            _logger = logger;
            _contextAccessor = contextAccessor;
            _serviceBusConfig = serviceBusOptions.Value;
        }       

        [Route("/sendmessage"), HttpPost]        
        public async Task<IActionResult> SendMessage()
        {
            var client = new ServiceBusClient(_serviceBusConfig.ConnectionString);
            var sender = client.CreateSender(_serviceBusConfig.TargetQueue);

            //send message with context
            await sender.SendMessageAsync(new ServiceBusMessage("test"), _contextAccessor);

            return Ok();
        }

    }

Receive Message With Context

Mainly call the extension method InitializeContext<T>(context) of Func<ProcessMessageEventArgs, Task> and register it with the servicebus processor, it will help to build the context from the received message.

var client = new ServiceBusClient(connectionString);
var processor = client.CreateProcessor(targetQueue);

//define context
var localContextAccessor = new LocalContextAccessor<SampleContext>((args) =>
{
    return (false, null);
});

//define the default handler
Func<ProcessMessageEventArgs, Task> messageHandler = args =>
{
    Console.WriteLine(args.Message.Body.ToString());
    Console.WriteLine("correlationid: " + localContextAccessor.Context?.CorrelationId);
    Console.WriteLine("payload->name: "+ localContextAccessor.Context?.Payload?.Name);
    Console.WriteLine("payload->sampledata: "+localContextAccessor.Context?.Payload?.SampleData);
    
    Console.WriteLine("Thread Id: "+ Thread.CurrentThread.ManagedThreadId.ToString());
    return Task.CompletedTask;
};

//call extension method to initialize context
processor.ProcessMessageAsync += messageHandler.InitializeContext(localContextAccessor, (args) => { return (false, null); });