Asp.net Core 2.2 read from Azure Service Bus Topic

Question

Good day i am writing an applicaiton that needs to read data from an Azure service bus topic. The registration function looks like this(see below). I would like to run this once on startup of The Asp.net Core application.

What would a good way to call this function since it seems IStartupFilter does not support async functions?

Any help would be greatly appreciated

    async Task RegisterForMessages()
    {
        subscriptionClient = new SubscriptionClient(constring, TopicName, SubscriptionName);

        // Register subscription message handler and receive messages in a loop
        RegisterOnMessageHandlerAndReceiveMessages();

        await subscriptionClient.CloseAsync();
    }

Answer 1

Have you tried creating interface base approach for registering Async function like below:

public interface IStartupAction
{
    Task ExecuteAsync(CancellationToken cancellationToken = default);
}

And a method for registering startup tasks with the DI container:

public static class ServiceCollectionExtensions
{
    public static IServiceCollection AddStartupTask<T>(this IServiceCollection services)
        where T : class, IStartupTask
        => services.AddTransient<IStartupAction, T>();
}

Finally, we add an extension method that finds all the registered IStartupAction on app startup, runs them in order, and then starts the IWebHost :

public static class StartupTaskWebHostExtensions
{
    public static async Task RunWithTasksAsync(this IWebHost webHost, CancellationToken cancellationToken = default)
    {
        // Load all tasks from DI
        var startupTasks = webHost.Services.GetServices<IStartupAction>();

        // Execute all the tasks
        foreach (var startupTask in startupTasks)
        {
            await startupTask.ExecuteAsync(cancellationToken);
        }

        // Start the tasks as normal
        await webHost.RunAsync(cancellationToken);
    }
}

For detailed steps , you can refer this doc.

Hope it helps.