I introduced Docker to Rails 6, so I summarized it (beginner)

Purpose

Since I implemented the portfolio and introduced docker, I will output it. I didn't know what docker was, so I refer to qiita from various people.

Docker installation

I saw this article and installed it! !! https://qiita.com/kurkuru/items/127fa99ef5b2f0288b81 After installation, execute the following command.

 % docker run -d -p 80:80 docker/getting-started

Confirmation of installation

% docker -v

Installation is complete when a command like this appears.

Docker version 20.10.2, build 2291f61

% docker-compose -v

 This is also complete when ``` docker-compose version 1.27.4, build 40524192``` is output.
# Over the introduction of Docker
 As a merit, you can execute rails and mysql built in the local environment with just one command. It was written as `` `, but it was difficult for me as a beginner to understand. After introducing docker, I understood this meaning, so it is better to move your hand first.


# Introducing docker in an app under development
 I will introduce it immediately.
 *** The framework uses Ruby on Rails 6. *** ***
### Creating a Dockerfile
 As a procedure, go to the application under development where you want to install Docker

~ %cd app name

app name% touch Dockerfile

 Since the Dockerfile has been created, please describe the following.

```dockerfile
FROM ruby:2.6.5 

RUN apt-get update -qq && \
    apt-get install -y build-essential \
                       libpq-dev \
                       nodejs

RUN mkdir /app name
WORKDIR /app name

ADD ./Gemfile /app name/Gemfile
ADD ./Gemfile.lock /app name/Gemfile.lock

RUN gem install bundler
RUN bundle install
ADD . /app name

Change the app name to the name of the app you are developing.

Let's create Docker-compose.yml.

app name% touch docker-compose.yml

Let's write the following.

docker-compose.yml

version: '3'
services:
  db:
    image: mysql:5.7
    environment:
      MYSQL_ROOT_PASSWORD: 'password' #It works fine as a password as it is
    ports:
      - "4306:3306" #Settings required for connecting to Docker container and Sequelpro

  web:
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/app name
    ports:
      - "3000:3000"
    depends_on:
      - db
      

Edit config/database.yml

config/database.yml

default: &default
  adapter: mysql2
  encoding: utf8
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  username: root
  password: password
  socket: /tmp/mysql.sock
  host: db
development:
  <<: *default
  database:app name_development


production.
test:
  <<: *default
  database:app name_test

Only password and `` `host: db``` have been added

Create a container with docker-compose.yml build

app name% docker-compose build

If there are no errors, it is successful.

Create DB and execute migrate on container

app name% docker-compose run web bundle exec rails db:create

If it is Rails6, an error will occur when this command is executed, so edit it.

config/webpacker.yml

  # Verifies that correct packages and versions are installed by inspecting package.json, yarn.lock, and node_modules
  check_yarn_integrity: false

Approximately line 56 `check_yarn_integrity: true``` Since it is, change this to `false```.

When you're done editing, run the same command again. Next, let's migrate.

app name% docker-compose run web bundle exec rake db:migrate

Now you have a db design on the container. Finally, let's start the container.

app name% docker-compose up 

Installation is complete if you can access localhost: 3000 and start it.

Launch from docker hub

Since multiple apps are loaded in the container, you can start the app with just one click without typing a command. You can start it by clicking the red RAN.

You can stop it by clicking it again.

Wordbook

① What is a docker file

The material that creates the container. When I executed the command `` `docker-compose build```, I think that it was loaded in steps. If the reading is successful, it means that the container has been created.

② What is docker-compose?

A tool for moving multiple containers at the same time

It's like this! I will do my best to write in more detail.