Publishing Message from AppHost Reference

ServiceStack Messaging
1

First, Happy Holidays. Thanks for all the support!

I’m using the Coravel scheduling library and looking at using the MQ Background Server in Service Stack to publish a message. This is setup in the startup.cs and the only reference I have is to the AppHost so my question is, “Is this the correct way to publish the message from the AppHost’s reference?”

appHost.Resolve<IMessageService>().MessageFactory.CreateMessageProducer().Publish(new WeeklyReportScheduler()))

A more full set of code:

  public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
    
            appHost = new AppHost
            {
                AppSettings =  new MultiAppSettings(
                    new EnvironmentVariableSettings(),
                    new NetCoreAppSettings(Configuration),
                    new AppSettings())
            };

            app.UseServiceStack(appHost);
            
            var provider = app.ApplicationServices;
                    
            provider.UseScheduler(scheduler =>
            {
   
                scheduler.Schedule(()=>  appHost.Resolve<IMessageService>().MessageFactory.CreateMessageProducer().Publish(new WeeklyReportScheduler())).DailyAtHour(14);
  
            }).OnError((exception) =>
                Console.WriteLine(exception.Message)
            );
        }
2

You should only start publishing messages after the Background MQ Server has started, e.g:

AfterInitCallbacks.Add(host => {
    mqServer.Start();
});

Or you can use ServiceStackHost.IsReady() to check if the AppHost is initialized.

I’d recommend using the same AppHost PublishMessage API the services use, e.g:

var host = HostContext.AppHost;
host.PublishMessage(host.GetMessageProducer(), new WeeklyReportScheduler());

Although you could also execute the Service in the Scheduler callback, e.g:

HostContext.AppHost.ExecuteService(new WeeklyReportScheduler());
1 Like
3

Thanks. My code worked but I felt that maybe I didn’t need to call CreateMessageProducer. You pointed me in the right place. A few notes:

  • I had it working originally with ExecuteService which was the easiest way to do this probably but I wanted to push it to the MQ service
  • The scheduler executes the method (at a certain time of the day) after the mq server starts so there is no issue there
1 Like