After much toil and trial and error I managed to issue a "request" from my saga and see it handle the response. My jubilation was cut short however by the appearance of a message in my states' skipped queue. (i'm using azure service bus)
It is of type "urn:message:MassTransit.Scheduling:CancelScheduledMessage".
I am a complete newbie at with mass transit and I'm just trying to get a contrived example going.
My saga calls TaxiToRunway/TaxiingComplete. My bit of saga code
Request(()=>TaxiToRunway, config =>
{
config.Timeout = TimeSpan.FromSeconds(30);
});
...
public Request<PlaneState, TaxiToRunway, TaxiingComplete> TaxiToRunway { get; private set; }
...
Initially(
When(ReadyToDepart)
.Then(context =>
{
context.Saga.Altitude = 0;
context.Saga.Speed = 0;
context.Saga.FlightNo = context.Message.FlightNo;
context.Saga.CorrelationId = context.Message.CorrelationId;
Console.WriteLine($"Flight {context.Message.FlightNo} is ready to depart.");
})
.TransitionTo(Taxiing)
.Request(TaxiToRunway,
(context) => context.Init<TaxiToRunway>(new {CorrelationId = context.Saga.CorrelationId}))
...
During(Taxiing,
Ignore(ReadyToDepart),
When(TaxiToRunway.Completed)
.Then(x =>
{
x.ToString();
})
.TransitionTo(TakingOff),
With a debugger attached I hit the x.ToString() line.
The consumer (in a different host):
public class TaxiToRunwayConsumer: IConsumer<TaxiToRunway>
{
public async Task Consume(ConsumeContext<TaxiToRunway> context)
{
await context.RespondAsync<TaxiingComplete>(new
{
context.Message.CorrelationId
});
}
}
Saga startup config:
cfg.AddSagaStateMachine<PlaneStateMachine, PlaneState>()
.MessageSessionRepository();
cfg.AddServiceBusMessageScheduler();
cfg.UsingAzureServiceBus((context, sbCfg) =>
{
var connectionString = appConfig.ServiceBus.ConnectionString;
sbCfg.Host(connectionString);
EndpointConvention.Map<TaxiToRunway>(new Uri("sb://xxx.servicebus.windows.net/taxi-to-runway"));
sbCfg.UseServiceBusMessageScheduler();
sbCfg.ReceiveEndpoint("plane-state", e =>
{
e.UseInMemoryOutbox();
e.RequiresSession = true;
e.PrefetchCount = 50;
e.MaxConcurrentCalls = 50;
e.ConfigureSaga<PlaneState>(context);
});
sbCfg.ConfigureEndpoints(context);
});
I can see this in the log output:
dbug: MassTransit.Messages[0]
SEND sb://dbpdf-us-dev-sam.servicebus.windows.net/plane-state 80d90000-5d7b-2cf0-7a6b-08da0fd3e7b7 MassTransit.Scheduling.CancelScheduledMessage
Am I supposed to be handling this as an event??
Learning curve on this sure is steep! My question is what do I need to do to not have these messages go to skipped?
So, the reason this doesn't work:
The message session saga repository can only correlate by the SessionId, since it's session-stored data.
The requestId, therefore, MUST equal the saga instance correlationId (aka, the SessionId)
The timeout message, sent by the request, gets a tokenId based upon the sequence number of the scheduled message
Which isn't saved anywhere
So the request timeout isn't canceled
The proper approach, in this scenario, is to use a Request/Response that doesn't have a timeout and use a separate Schedule to schedule the timeout yourself.
Related
I have a producer, which send more than 1000 messages in a minute to a specific endpoint. I’m using Microsoft DI and I’ve configured the send Endpoint as described here https://masstransit-project.com/usage/producers.html#send .
// Masstransit setup
serviceCollection.AddMassTransit(mt =>
{
mt.UsingAzureServiceBus((ctx, cfg) =>
{
cfg.Host(massTransitSettings.TestServiceBusConnectionString);
cfg.ReceiveEndpoint("mytestmessage", e =>
{
e.MaxDeliveryCount = 3; //How many times the transport will redeliver the message on negative acknowledgment
});
});
});
serviceCollection.AddTransient<ITestMessageProducer, TestMessageProducer>();
// Producer setup
public class TestMessageProducer : ITestMessageProducer
{
private readonly ISendEndpointProvider _testEndpoint;
public TestMessageProducer(ISendEndpointProvider testEndpoint)
{
_testEndpoint = testEndpoint;
}
public async Task SendTestMessage(ITestMessage testmessage)
{
var endpoint = await _testEndpoint.GetSendEndpoint(new Uri("queue:mytestmessage"));
await endpoint.Send(testmessage);
}
}
Query:
The SendTestMessage function has been called very frequently as mention above. Will it be ok to call “GetSendEndpoint” everytime? I have read somewhere that GetSendEndpoint creates a new instance of ISendEndpoint everytime.
Will the MaxDeliveryCount still be worked on my sendendpoint?
Thank you.
Send endpoints are cached by address, only a single instance will be created.
MaxDeliveryCount is a receive endpoint concern, but you should not configure a receive endpoint without consumers as all messages will be moved to the _skipped queue.
I'm running a MassTransit configuration with AmazonSQS. In my program I start by creating a receiveenpoint with the queue "input-queue1", I subscribe this SQS queue to an SNS topic named "topic1" and associate a consumer to this receiveendpoint that does some standard printing of the messages it receives. After starting the bus i want to subscribe the already created queue "input-queue1" to another SNS topic, named "topic2", but I couldn't find a way of doing this after starting the Bus (It's important to me that i can do this after the Bus is started). Is there a way of doing this and i'm just missing something, or is it not possible at all? (I tried with the commented portion of the code but it didn't work)
class Program
{
static async Task Main(string[] args)
{
var bus = Bus.Factory.CreateUsingAmazonSqs(x =>
{
x.Host(Constants.Region, h =>
{
h.AccessKey(Constants.AccesskeyId);
h.SecretKey(Constants.SecretAccessKey);
});
x.ReceiveEndpoint("input-queue1", e =>
{
e.Subscribe("topic1", callback => { });
e.Consumer(() => new Handler());
});
});
bus.StartAsync().Wait();
/*var handle = bus.ConnectReceiveEndpoint("input-queue1", e => {
e.Subscribe("topic2", callback => { });
});
var ready = await handle.Ready;*/
Console.WriteLine("Listening to messages...");
Console.WriteLine("Press enter to quit");
Console.ReadLine();
}
}
You can't change the topology of a receive endpoint once it has been created. This means that no new topic subscriptions can be created, and existing subscriptions cannot be removed.
If you need to change the configuration of the receive endpoint, you would need to do it yourself by using the SNS API to add the subscription yourself. I would question why you would want to do this though. If the consumer isn't able to consume the message forwarded to the queue, it would be moved to the skipped queue.
I've been trying to come up with a demo of a website that uses MassTransit with RabbitMQ to post messages to a service running on Service Fabric as a Stateful service.
Everything was going fine, my client would post a message:
IBusControl bus = BusConfigurator.ConfigureBus();
Uri sendToUri = new Uri($"{RabbitMqConstants.RabbitMqUri}" + $"{RabbitMqConstants.PeopleServiceQueue}");
ISendEndpoint endPoint = await bus.GetSendEndpoint(sendToUri);
await endPoint.Send<ICompanyRequest>(new {CompanyId = id });
My consumer in my service fabric service was defined like:
IBusControl busControl = Bus.Factory.CreateUsingRabbitMq(cfg =>
{
IRabbitMqHost host = cfg.Host(new Uri(RabbitMqConstants.RabbitMqUri), h =>
{
h.Username(RabbitMqConstants.UserName);
h.Password(RabbitMqConstants.Password);
});
cfg.ReceiveEndpoint(host, RabbitMqConstants.PeopleServiceQueue, e =>
{
e.Consumer<PersonInformationConsumer>();
});
});
busControl.Start();
This does allow me to consume the message in my class and I can process it fine. The problem comes when we want to use IReliableDictonary or IReliableQueue or anything that needs to reference the context that is run from the RunAsync function in the service fabric service.
So my question is, how can I configure (is it possible) MassTransit to work within a Stateful Service Fabric Service which knowledge of the service context itself?
Many thanks in advance.
Mike
Update
Ok, I've made some progress on this, if I point the register routines to my message consumer class (eg):
ServiceRuntime.RegisterServiceAsync("ServiceType", context => new PersonInformationConsumer(context)).GetAwaiter().GetResult();
ServiceEventSource.Current.ServiceTypeRegistered(Process.GetCurrentProcess().Id, typeof(PersonInformationConsumer).Name);
Then in my consumer class for my messages I can do the following:
internal sealed class PersonInformationConsumer : StatefulService, IConsumer<ICompanyRequest>
{
private static StatefulServiceContext _currentContext;
#region Constructors
public PersonInformationConsumer(StatefulServiceContext serviceContext) : base(serviceContext)
{
_currentContext = serviceContext;
}
public PersonInformationConsumer() : base(_currentContext)
{
}
I can now successfully call the service message:
ServiceEventSource.Current.ServiceMessage(this.Context, "Message has been consumed, request Id: {0}", context.Message.CompanyId);
The problem I have now is trying to store something on the IReliableDictionary, doing this causes as "Object reference not set to an instance of an object" error :( ... any ideas would be appreciated (although may not read until new year now!)
public async Task Consume(ConsumeContext<ICompanyRequest> context)
{
ServiceEventSource.Current.ServiceMessage(this.Context, "Message has been consumed, request Id: {0}", context.Message.CompanyId);
using (ITransaction tx = StateManager.CreateTransaction())
{
try
{
var myDictionary = await StateManager.GetOrAddAsync<IReliableDictionary<string, long>>("myDictionary");
This is causing the error.... HELP! :)
You'll need to do a bit more to get MassTransit and stateful services working together, there's a few issues to concern yourself here.
Only the master within a stateful partition (n masters within n partitions) will be able to write/update to the stateful service, all replicas will throw exceptions when trying to write back any state. So you'll need to deal with this issue, on the surface it sounds easy until you take in to consideration the master can move around the cluster due to re-balancing the cluster, the default for general service fabric applications is to just turn off the processing on the replicas and only run the work on the master. This is all done by the RunAsync method (try it out, run 3 stateful services with something noddy in the RunAsync method, then terminate the master).
There is also partitioning of your data to consider, due to stateful services scale with partitions, you'll need to create a way to distributing data to separate endpoint on your service bus, maybe have a separate queue that only listens to a given partition range? Say you have a UserCreated message, you might split this on country UK goes to partition 1, US goes to partition 2 etc...
If you just want to get something basic up and running, I'd limit it to one partition and just try putting your bus creation within the the RunAsync and shutdown the bus once a cancelation is requested on the cancelation token.
protected override async Task RunAsync(CancellationToken cancellationToken)
{
var busControl = Bus.Factory.CreateUsingRabbitMq(cfg =>
{
IRabbitMqHost host = cfg.Host(new Uri(RabbitMqConstants.RabbitMqUri), h =>
{
h.Username(RabbitMqConstants.UserName);
h.Password(RabbitMqConstants.Password);
});
cfg.ReceiveEndpoint(host, RabbitMqConstants.PeopleServiceQueue, e =>
{
// Pass in the stateful service context
e.Consumer(c => new PersonInformationConsumer(Context));
});
});
busControl.Start();
while (true)
{
if(cancellationToken.CancellationRequested)
{
//Service Fabric wants us to stop
busControl.Stop();
cancellationToken.ThrowIfCancellationRequested();
}
await Task.Delay(TimeSpan.FromSeconds(1));
}
}
I have problem retrieve Azure messages from Queue on Windows Phone 7.
To add message I am using such code:
var queueClient = CloudStorageContext.
Current.
Resolver.
CreateCloudQueueClient() as CloudQueueClient;
var queue = queueClient.GetQueueReference("queuein");
queue.Create(
r => queue.AddMessage(
new CloudQueueMessage { AsBytes = Encoding.UTF8.GetBytes(msg) },
c =>
{
// Some logic here.
}));
To get message back it looks like I have to follow similar principle and use queue instance.
But GetMessage() method has VOID return type:
Could you guys help me to understand what the hell is going on in Mobile version of Azure queues, because in Windows console application those methods has return type.
Async patterns are a bit different on the phone. You need to handle the message in the callback function.
ShowAmWorkingInUILol = true;
// snip
queue.GetMessage(TimeSpan.FromMinutes(1), OnMessageReturned);
}
private void OnMessageReturned(CloudOperationResponse<CloudQueueMessage> response)
{
ShowAmWorkingInUILol = false;
// here's your response.
}
I have a Action that sends a simple email:
[HttpPost, ActionName("Index")]
public ActionResult IndexPost(ContactForm contactForm)
{
if (ModelState.IsValid)
{
new EmailService().SendAsync(contactForm.Email, contactForm.Name, contactForm.Subject, contactForm.Body, true);
return RedirectToAction(MVC.Contact.Success());
}
return View(contactForm);
}
And a email service:
public void SendAsync(string fromEmail, string fromName, string subject, string body, bool isBodyHtml)
{
MailMessage mailMessage....
....
SmtpClient client = new SmtpClient(settingRepository.SmtpAddress, settingRepository.SmtpPort);
client.EnableSsl = settingRepository.SmtpSsl;
client.Credentials = new NetworkCredential(settingRepository.SmtpUserName, settingRepository.SmtpPassword);
client.SendCompleted += client_SendCompleted;
client.SendAsync(mailMessage, Tuple.Create(client, mailMessage));
}
private void client_SendCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
{
Tuple<SmtpClient, MailMessage> data = (Tuple<SmtpClient, MailMessage>)e.UserState;
data.Item1.Dispose();
data.Item2.Dispose();
if (e.Error != null)
{
}
}
When I send a email, I am using Async method, then my method SendAsync return immediately, then RedirectToAction is called. But the response(in this case a redirect) isn´t sent by ASP.NET until client_SendCompleted is completed.
Here's what I'm trying to understand:
When watching the execution in Visual Studio debugger, the SendAsync returns immediately (and RedirectToAction is called), but nothing happens in the browser until email is sent?
If i put a breakpoint inside client_SendCompleted, the client stay at loading.... until I hit F5 at debugger.
This is by design. ASP.NET will automatically wait for any outstanding async work to finish before finishing the request if the async work was kicked off in a way that calls into the underlying SynchronizationContext. This is to ensure that if your async operation tries to interact with the HttpContext, HttpResponse, etc. it will still be around.
If you want to do true fire & forget, you need to wrap your call in ThreadPool.QueueUserWorkItem. This will force it to run on a new thread pool thread without going through the SynchronizationContext, so the request will then happily return.
Note however, that if for any reason the app domain were to go down while your send was still in progress (e.g. if you changed the web.config file, dropped a new file into bin, the app pool recycled, etc.) your async send would be abruptly interrupted. If you care about that, take a look at Phil Haacks WebBackgrounder for ASP.NET, which let's you queue and run background work (like sending an email) in such a way that will ensure it gracefully finishes in the case the app domain shuts down.
This is an interesting one. I've reproduced the unexpected behaviour, but I can't explain it. I'll keep digging.
Anyway the solution seems to be to queue a background thread, which kind of defeats the purpose in using SendAsync. You end up with this:
MailMessage mailMessage = new MailMessage(...);
SmtpClient client = new SmtpClient(...);
client.SendCompleted += (s, e) =>
{
client.Dispose();
mailMessage.Dispose();
};
ThreadPool.QueueUserWorkItem(o =>
client.SendAsync(mailMessage, Tuple.Create(client, mailMessage)));
Which may as well become:
ThreadPool.QueueUserWorkItem(o => {
using (SmtpClient client = new SmtpClient(...))
{
using (MailMessage mailMessage = new MailMessage(...))
{
client.Send(mailMessage, Tuple.Create(client, mailMessage));
}
}
});
With .Net 4.5.2, you can do this with ActionMailer.Net:
var mailer = new MailController();
var msg = mailer.SomeMailAction(recipient);
var tcs = new TaskCompletionSource<MailMessage>();
mailer.OnMailSentCallback = tcs.SetResult;
HostingEnvironment.QueueBackgroundWorkItem(async ct =>
{
msg.DeliverAsync();
await tcs.Task;
Trace.TraceInformation("Mail sent to " + recipient);
});
Please read this first: http://www.hanselman.com/blog/HowToRunBackgroundTasksInASPNET.aspx
I sent the bug to Microsoft Connect https://connect.microsoft.com/VisualStudio/feedback/details/688210/smtpclient-sendasync-blocking-my-asp-net-mvc-request