Odtnhj

I am trying to do multiple node distribution systems by multiple Rails node + docker + MySQL + Redis.

Therefore, my main node needs to communicate with other nodes.

Here is my docker-compose.yml

**version: '2'
services:
 db:
 image: mysql:5.7
 restart: always
 environment:
 - MYSQL_ROOT_PASSWORD=password
 - MYSQL_DATABASE=pubsub_1_development
 - MYSQL_USER=appuser
 - MYSQL_PASSWORD=password
 ports:
 - "3308:3306"

 redis:
 image: 'redis:4.0-alpine'

 app:
 image: pubsub_2:1.0.8
 command: /bin/sh -c "rm -f ./tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
 volumes:
 - ".:/pubsub_2"
 ports:
 - "3001:3000"
 depends_on:
 - db
 - redis
 - sub_node
 - pub_node
 links:
 - db
 - redis
 - sub_node
 - pub_node
 environment:
 DB_USER: root
 DB_NAME: pubsub_1_development
 DB_PASSWORD: password
 DB_HOST: db
 REDIS_CABLE_PORT: redis://redis:6379/1
 SUB_NODE: 0.0.0.0:4001
 PUB_NODE: 0.0.0.0:4000
 stdin_open: true
 tty: true

 sub_node:
 image: sub_node:1.0.1
 command: /bin/sh -c "rm -f /sub_node/tmp/pids/server.pid && bundle exec rails s -p 4001 -b '0.0.0.0'"
 ports:
 - "4001:4001"
 environment:
 DB_USER: root
 DB_NAME: pubsub_1_development
 DB_PASSWORD: password
 DB_HOST: db
 REDIS_CABLE_PORT: redis://redis:6379/1
 tty: true
 expose:
 - "4001"


 pub_node:
 image: pub_node:1.0.1
 command: /bin/sh -c "rm -f /pub_node/tmp/pids/server.pid && bundle exec rails s -p 4000 -b '0.0.0.0'"
 ports:
 - "4000:4000"
 environment:
 DB_USER: root
 DB_NAME: pubsub_1_development
 DB_PASSWORD: password
 DB_HOST: db
 REDIS_CABLE_PORT: redis://redis:6379/1
 tty: true
 expose:
 - "4000"**

However, when I try to use app node to send the request to pub_node, it threw this error.

Errno::ECONNREFUSED: Failed to open TCP connection to 127.0.0.1:4000 (Connection refused - connect(2) for "127.0.0.1" port 4000)
from /usr/local/lib/ruby/2.5.0/net/http.rb:939:in `rescue in block in connect'

I was doing post by this code.

rvlist = '127.0.0.1:4000'
HTTParty.post("http://#rvlist/publish", options)

It works in my development mode without the docker environment.

Networking in docker-compose:

Each container for a service joins the default network and is both
reachable by other containers on that network, and discoverable by
them at a hostname identical to the container name.

Reference: https://docs.docker.com/compose/networking/

In your case, any container within docker-compose can open the TCP connection to pub_node container using its container name and port pub_node:4000