RabbitMq refuses connection when run in docker - sockets

Question

My docker-compose file looks like this:
version: '2'
services:
explore:
image: explore
build:
context: ./Explore
dockerfile: VsDockerfile
environment:
- "ElasticUrl=http://localhost:9200"
- "RabbitMq/Host=localhost"
- "RabbitMq/Username=guest"
- "RabbitMq/Password=guest"
networks:
- localnet
elasticsearch:
image: docker.elastic.co/elasticsearch/elasticsearch:5.4.3
container_name: elasticsearch
environment:
- "ES_JAVA_OPTS=-Xms512m -Xmx512m"
ports:
- 9200:9200
volumes:
- ./esdata:/usr/share/elasticsearch/data
networks:
- localnet
rabbit:
image: rabbitmq:3.6.7-management
hostname: rabbit
ports:
- 15672:15672
- 5672:5672
networks:
- localnet
networks:
localnet:
external:
name: localnet
If I type http://localhost:15672 in the browser, I get the rabbitmq interface, but if I tries to connect from my Explore project like this:
public SqlToRabbitProcessor(SqlToRabbitRepository sqlToRabbitRepository)
{
_sqlToRabbitRepository = sqlToRabbitRepository;
var factory = new ConnectionFactory
{
HostName = Environment.GetEnvironmentVariable("RabbitMq/Host"),
UserName = Environment.GetEnvironmentVariable("RabbitMq/Username"),
Password = Environment.GetEnvironmentVariable("RabbitMq/Password")
};
var rabbit = factory.CreateConnection();
channel = rabbit.CreateModel();
}
Then it breaks in the line
var rabbit = factory.CreateConnection();
with the error saying
ExtendedSocketException: Connection refused 127.0.0.1:5672
System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
ConnectFailureException: Connection failed
RabbitMQ.Client.EndpointResolverExtensions.SelectOne(IEndpointResolver resolver, Func selector)
BrokerUnreachableException: None of the specified endpoints were reachable
RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, string clientProvidedName)

Answer 1

As my comment under the question suggested, it's because the "localhost" defined in the web application part is it's containers localhost, and not the docker host..
just needed to change
- "ElasticUrl=http://localhost:9200"
- "RabbitMq/Host=localhost"
to
- "ElasticUrl=http://elasticsearch:9200"
- "RabbitMq/Host=rabbit"

Answer 2

I had the same issue with docker-compose.
I solved it by with hostname:
rabbit:
hostname: rabbit
command: sh -c "rabbitmq-plugins enable rabbitmq_management; rabbitmq-server"
image: rabbitmq
environment:
RABBITMQ_DEFAULT_USER: admin
RABBITMQ_DEFAULT_PASS: admin
ports:
- 5672:5672
- 15672:15672

Answer 3

Follow instructions on this post.
Just to benefit people that stumble upon this question. The --link feature is now considered legacy and is a prime candidate to be deprecated by docker.
The easiest way is to use
depends_on:
In order to do this, its recommended to first create a network like so"
docker network create <network_name>
Then use docker-compose up to spawn services that bind with each other. Look at the example below where I've bound my spring-boot app to rabbit-mq. You can clone my repo from here
version: "3.1"
services:
rabbitmq-container:
image: rabbitmq:3.5.3-management
hostname: rabbitmq-container
ports:
- 5673:5673
- 5672:5672
- 15672:15672
networks:
- resolute
resolute-container:
build: .
ports:
- 8080:8080
environment:
- spring_rabbitmq_host=rabbitmq-container
- spring_rabbitmq_port=5672
- spring_rabbitmq_username=guest
- spring_rabbitmq_password=guest
- resolute_rabbitmq_publishQueueName=resolute-run-request
- resolute_rabbitmq_exchange=resolute
depends_on:
- rabbitmq-container
volumes:
- /var/run/docker.sock:/var/run/docker.sock
networks:
- resolute
networks:
resolute:
external:
name: resolute
See how I've created a network called resolute and bound the apps to the same network. I've also given my rabbitmq-container a hostname. This is because docker now prepends the container name and that makes it difficult to bind services by name.