Unable to connect to MySql using gitlab-ci.yml

Question

I'm trying to create gitlab-ci file for my Rails project. A part of my .gitlab-ci.yml:

image: ruby:2.3.4

variables:
  RAILS_ENV: test

services:
  - mysql:5.7


before_script:
  - apt-get update -qq && apt-get install -yqq nodejs libmysqlclient-dev
  - ruby -v
  - which ruby
  - gem install bundler --no-ri --no-rdoc
  - bundle install --jobs $(nproc) "${FLAGS[@]}"
  - cp config/database.gitlab_ci.yml config/database.yml
  - bundle exec rake db:create db:schema:load
  - bundle exec rake db:migrate --quiet

I haven't been able to get it to connect to my MySql db. No matter what I tried.

Here's a part of my database.gitlab_ci.ym:

test: &test
    adapter: mysql2
    database: my_db
    encoding: utf8
    username: my_user
    password: 1234
    host: localhost

I've always gotten this error:

  #<Mysql2::Error: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)>
  Couldn't create database for {"adapter"=>"mysql2", "database"=>"my_db", "encoding"=>"utf8", "username"=>"my_db", "password"=>1234, "host"=>"localhost"}, {:charset=>"utf8"}
  (If you set the charset manually, make sure you have a matching collation)
  rake aborted!
  Mysql2::Error: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

How to fix it?

Answer 1

Your mysql service won't be available at localhost.
You have to use the service name mysql as hostname.
See Documentation.