Masstransit cannot access host machine RabbitMQ from a docker container - rabbitmq

Question

I created a simple .net core console application with docker support. Following
Masstransit code fails to connect to RabbitMQ instance on host machine. But similar implementation using RabitMq.Client is able to connect to host machine RabbitMQ instance.
Masstransit throws
MassTransit.RabbitMqTransport.RabbitMqConnectionException: Connect
failed: ctas#192.168.0.9:5672/ --->
RabbitMQ.Client.Exceptions.BrokerUnreachableException:
host machine ip : 192.168.0.9
using Masstransit
string rabbitMqUri = "rabbitmq://192.168.0.9/";
string userName = "ctas";
string password = "ctas#123";
string assetServiceQueue = "hello";
var bus = Bus.Factory.CreateUsingRabbitMq(cfg =>
{
var host = cfg.Host(new Uri(rabbitMqUri), hst =>
{
hst.Username(userName);
hst.Password(password);
});
cfg.ReceiveEndpoint(host,
assetServiceQueue, e =>
{
e.Consumer<AddNewAssetReceivedConsumer>();
});
});
bus.Start();
Console.WriteLine("Service Running.... Press enter to exit");
Console.ReadLine();
bus.Stop();
Using RabbitMQ Client
public static void Main()
{
var factory = new ConnectionFactory();
factory.UserName = "ctas";
factory.Password = "ctas#123";
factory.VirtualHost = "watcherindustry";
factory.HostName = "192.168.0.9";
using (var connection = factory.CreateConnection())
using (var channel = connection.CreateModel())
{
channel.QueueDeclare(queue: "hello",
durable: false,
exclusive: false,
autoDelete: false,
arguments: null);
var consumer = new EventingBasicConsumer(channel);
consumer.Received += (model, ea) =>
{
var body = ea.Body;
var message = Encoding.UTF8.GetString(body);
Console.WriteLine(" [x] Received {0}", message);
};
channel.BasicConsume(queue: "hello",
autoAck: true,
consumer: consumer);
Console.WriteLine(" Press [enter] to exit.");
Console.ReadLine();
}
}
Docker file
FROM microsoft/dotnet:1.1-runtime
ARG source
WORKDIR /app
COPY ${source:-obj/Docker/publish} .
ENTRYPOINT ["dotnet", "TestClient.dll"]

Answer 1

I created an example, and was able to connect my host, using the preview package from masstransit.
Start rabbitmq in docker and expose ports on the host
docker run -d -p 5672:5672 -p 15672:15672 --hostname my-rabbit --name some-rabbit rabbitmq:3-management
Build and run console app.
docker build -t dotnetapp .
docker run -d -e RABBITMQ_URI=rabbitmq://guest:guest#172.17.0.2:5672 --name some-dotnetapp dotnetapp
To verify your receiving messages run
docker logs some-dotnetapp --follow
you should see the following output
Application is starting...
Connecting to rabbitmq://guest:guest#172.17.0.2:5672
Received: Hello, World [08/12/2017 04:35:53]
Received: Hello, World [08/12/2017 04:35:58]
Received: Hello, World [08/12/2017 04:36:03]
Received: Hello, World [08/12/2017 04:36:08]
Received: Hello, World [08/12/2017 04:36:13]
...
Notes:
172.17.0.2 was my-rabbit container ip address but you can replace it with your machine ip address
http://localhost:15672 is the rabbitmq management console log in with guest as username and password.
Lastly portainer.io is a very useful application to visually view you local docker environment.

Answer 2

Thanks for the response. I managed to resolve this issue. My findings are as follows.
to connect to a rabbitmq instance on another docker container, they have to be moved/connected to the same network. To do this
create a newtork
docker network create -d bridge my_bridge
connect both app and rabbitmq containers to same network
docker network connect my_bridge <container name>
For masstransit uri use rabbitmq container IP on that network or container name
To connect rabbitmq instance of host machine from a app on docker container.
masstransit uri should include machine name( I tried IP, that did not work)

Answer 3

Try using virtual host in MassTransit configuration too, not sure why you decided to omit it.
var host = cfg.Host("192.168.0.9", "watcherindustry", hst =>
{
hst.Username(userName);
hst.Password(password);
});

Answer 4

Look at Alexey Zimarev comment to your question, if your rabbit runs on a container then it should be on your docker-compese file and then use that entry in your endpoint definition to connect to rabbit because docker creates an internal network on which you are agnostic from source code...
rabbitmq:
container_name: "rabbitmq-yournode01"
hostname: rabbit
image: rabbitmq:3.6.6-management
environment:
- RABBITMQ_DEFAULT_USER=yourusergoeshere
- RABBITMQ_DEFAULT_PASS=yourpasswordgoeshere
- RABBITMQ_DEFAULT_VHOST=vhost
volumes:
- rabbit-volume:/var/lib/rabbitmq
ports:
- "5672:5672"
- "15672:15672"
In your app settings you should have something lie:
"ConnectionString": "host=rabbitmq:5672;virtualHost=vhost;username=yourusergoeshere;password=yourpasswordgoeshere;timeout=0;prefetchcount=1",
And if you'd use EasyNEtQ you could do:
_bus = RabbitHutch.CreateBus(_connectionString); // The one above
I hope it helps,
Juan