NodeJS + Mysql with Docker Compose 2 - mysql

Question

I´m trying to built a docker-compose file to deploy locally my NodeJS app that connects to a mysql server. I´ve tried everything ( read a lot of tutorials and some questions here in Stackoverflow ) but I keep getting the ECONNREFUSED error.
This is my Dockerfile from NodeJS:
##Nodejs
FROM node:latest
RUN useradd --user-group --create-home --shell /bin/false app
ENV HOME=/home/app
COPY package.json npm-shrinkwrap.json $HOME/playerground/
RUN chown -R app:app $HOME/*
USER app
WORKDIR $HOME/playerground
RUN npm cache clean && npm install --silent --progress=false
USER root
COPY . $HOME/playerground
RUN chown -R app:app $HOME/*
USER app
This is my Mysql Dockerfile:
FROM mysql:latest
ENV MYSQL_ROOT_PASSWORD root
ENV MYSQL_DATABASE playerground
ENV MYSQL_USER root
ENV MYSQL_PASSWORD root
And this is my docker-compose:
version: '2'
services:
db:
build: ./database
ports:
- "3307:3306"
playerground:
build:
context: .
dockerfile: Dockerfile
command: node_modules/.bin/nodemon --exec npm start
environment:
ENVIRONMENT: development
ports:
- "9090:9090"
links:
- db
volumes:
- .:/home/app/playerground
- /home/app/playerground/node_modules
Another thing is my configuration file from Nodejs:
//Database
'development' : {
'host' : process.env.HOSTNAME || 'localhost',
'user' : 'root',
'password' : 'root',
'database' : 'playerground'
},
//Server
'development' : {
'host' : process.env.HOSTNAME || '127.0.0.1',
'port' : 3000
},
Can you help me?
Thanks

Answer 1

In your app config, the database host isn't pointing at your MySql container. You're pointing it at the local host, which is the app container. In the Compose file you can explicitly name the link to the db container using:
links:
- db:db
And then your database container can be reached at the hostname db. You can hard-code that host in your app config, because it will be the same for all environments, as long as you use the same Compose file.
Also, if you're using a recent version of Docker you don't need to publish ports between containers in the same Docker network - so you can remove this from your Compose file:
ports:
- "3307:3306"
Then the db container will be accessible by the app container, but not externally.