RabbitMq refuses connection when run in docker

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"