MT in the cloud with AppHarbor and CloudAMQP

Question

Anybody successfully got MassTransit working with AppHarbor and CloudAMQP?

I am having a bear of a time with it.

I have the publisher (the web site) sending messages, but the server (a background worker) does not appear to be picking them up.

One of the things that concern me is that MT requires the rabbitmq scheme whereas CloudAMQP sets the scheme to amqp.

I am swapping the scheme (from amqp to rabbitmq) when configuring the bus and noticed the scheme in the addresses of the message is rabbitmq, which makes sense, since I replaced them. But I am wondering if they have to be amqp for the server to pick them up?

Here is a simple message that I have sent, it got to RabbitMQ but server is not picking it up.

message_id: 08cf2cbc-5b4f-14dd-1231-381f8b520000
delivery_mode:  2
headers:    
Content-Type:   application/vnd.masstransit+json
Payload
614 bytes
Encoding: string
{

  "destinationAddress": "rabbitmq://98eabe2a-aae8-464c-8555-855518dd87d0_apphb.com:*********@lemur.cloudamqp.com/98eabe2a-aae8-464c-8555-855518dd87d0_apphb.com/Messages.Product:ProductCreatedEvent",

  "headers": {},

  "message": {

    "id": "dd6ecfaa-60d2-4cd4-8cd6-a08a00e872fb"

  },

  "messageType": [

    "urn:message:Messages.Product:ProductCreatedEvent"

  ],

  "retryCount": 0,

  "sourceAddress": "rabbitmq://98eabe2a-aae8-464c-8555-855518dd87d0_apphb.com:**********@lemur.cloudamqp.com/98eabe2a-aae8-464c-8555-855518dd87d0_apphb.com/enterprise_web"

}

Thanks, Joe

Edit: Thanks Carl pointing out the passwords in the url

you probably shouldn't post your password on a public site :P — Carl Hörberg, Jul 11 '12 at 20:07

score 7 · Accepted Answer · edited May 23 '17 at 10:34

Edit: To let anyone else thinking about using MassTransit with CloudAMQP, you may want to look into EasyNetQ instead. Not taking anything away from MassTransit, its a great project. The problem when using it with a service like CloudAMQP that charges data usage per month, is that MassTransit uses polling to check for messages, instead of subscribing to them (at least in the last version I was working with 2.1.1). This polling will eat into your data usage even though you may not be publishing messages.

Well it is in fact possible.

Come to find out, it was all part of the configuration of the background worker on appharbor.

Once that got worked out the background worker started staying "alive" and consuming messages. The issue revolved around app.config vs myworker.exe.config and config transforms. Once I realized it was a config problem this link helped out. App.config transformation for appharbor background workers

You have to swap out the amqp scheme for rabbitmq but that is not to bad. Here is my bus configuration for the background worker:

log.Info("Configuring MassTransit");
var rabbitUrl = ConfigurationManager.AppSettings["CLOUDAMQP_URL"];

var bus = ServiceBusFactory.New(sbc =>
{
    // configure for log4net
    sbc.UseLog4Net();

    // configure the bus
    sbc.UseRabbitMq();
    sbc.UseRabbitMqRouting();
    sbc.ReceiveFrom(String.Format("{0}/server", rabbitUrl.Replace("amqp://", "rabbitmq://"))); // need to swap the scheme for masstransit

    // finds all the consumers in the container and register them with the bus
    sbc.Subscribe(x => x.LoadFrom(container));

    sbc.BeforeConsumingMessage(() =>
    {
        var session = container.GetInstance<ISessionFactory>().OpenSession();
        CurrentSessionContext.Bind(session);
    });

    sbc.AfterConsumingMessage(() =>
    {
        var sessionFactory = container.GetInstance<ISessionFactory>();
        if (CurrentSessionContext.HasBind(sessionFactory) == false) return;

        var session = CurrentSessionContext.Unbind(sessionFactory);
        if (session != null)
        {
            session.Dispose();
        }
    });

    var results = sbc.Validate();
    if (results.Any())
    {
        throw new Exception("MassTransit may not be setup correctly. Review validate results");
    }
});

// finally inject the bus into the container
container.Inject(bus);

While this is possible, there is a catch. MT implements polling to check for new messages which will affect your message limits with CloudAMQP. — Joe Young, Jul 16 '12 at 14:09
So all you have done is swap out "amqp" with "rabbitmq"? Nothing else? Why have you added /server to the endpoint. My endpoint is amqp://da86b180-00f0-4812-a501-7ea3c525982e_apphb.com:****@tiger.cloudamqp.com/da86b180-00f0-4812-a501-7ea3c525982e_apphb.com. I just get BrokerUnreachableException: None of the specified endpoints were reachable — Sam, Aug 03 '12 at 03:02
The "server" part of the name of the queue, if I recall correctly. — Joe Young, Aug 03 '12 at 13:25
The polling has been replaced with a consumer now, so data usage should be zero when idle. — Chris Patterson, Oct 30 '12 at 13:51

score 1 · Answer 2 · answered Jul 10 '12 at 23:53

1

I'm not aware of anyone on the mailing who's done this. Good luck though, please report to the mailing list if you get it working.

The protocol of rabbitmq is used by MT to figure out what Transport to use.

Per the .NET docs for the RabbitMQ connector it should be using the amqp protocol. So this shouldn't be the issue; but can you connect to the instance from elsewhere?

answered Jul 10 '12 at 23:53

Travis

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Finally got it working, turned out to not be an MT issue. On another note, can someone check the settings for the mailing list group (masstransit-discuss). I have joined the group but cannot post messages and have had a couple other co-workers join with the same outcome, cannot create new topics. – Joe Young Jul 11 '12 at 17:12
Glad to hear you got it working! I'll make sure you guys get approved shortly. – Travis Jul 11 '12 at 17:45

MT in the cloud with AppHarbor and CloudAMQP

2 Answers2