Docker 和 docker-compose

首先，我們需要建立我們的 Dockerfile。Nick Janetakis 在這個部落格上可以找到一個很好的例子。

此程式碼包含將在啟動時在我們的 docker 機器上執行的指令碼。因此，我們正在安裝所有必需的庫，並以 Puma 的開頭結束（RoR 開發伺服器）

# Use the barebones version of Ruby 2.3.
FROM ruby:2.3.0-slim

# Optionally set a maintainer name to let people know who made this image.
MAINTAINER Nick Janetakis <nick.janetakis@gmail.com>

# Install dependencies:
# - build-essential: To ensure certain gems can be compiled
# - nodejs: Compile assets
# - libpq-dev: Communicate with postgres through the postgres gem
RUN apt-get update && apt-get install -qq -y --no-install-recommends \
      build-essential nodejs libpq-dev git

# Set an environment variable to store where the app is installed to inside
# of the Docker image. The name matches the project name out of convention only.
ENV INSTALL_PATH /mh-backend
RUN mkdir -p $INSTALL_PATH

# This sets the context of where commands will be running in and is documented
# on Docker's website extensively.
WORKDIR $INSTALL_PATH

# We want binstubs to be available so we can directly call sidekiq and
# potentially other binaries as command overrides without depending on
# bundle exec.
COPY Gemfile* $INSTALL_PATH/

ENV BUNDLE_GEMFILE $INSTALL_PATH/Gemfile
ENV BUNDLE_JOBS 2 
ENV BUNDLE_PATH /gembox

RUN bundle install

# Copy in the application code from your work station at the current directory
# over to the working directory.
COPY . .

# Ensure the static assets are exposed to a volume so that nginx can read
# in these values later.
VOLUME ["$INSTALL_PATH/public"]

ENV RAILS_LOG_TO_STDOUT true

# The default command that gets run will be to start the Puma server.
CMD bundle exec puma -C config/puma.rb

另外，我們將使用 docker-compose，為此，我們將建立 docker-compose.yml。這個檔案的解釋將更多是一個 docker-compose 教程而不是與 Rails 的整合，我不會在這裡介紹。

version: '2'

services:
  backend:
    links:
      - #whatever you need to link like db
    build: .
    command: ./scripts/start.sh
    ports:
      - '3000:3000'
    volumes:
      - .:/backend
    volumes_from:
      - gembox
    env_file:
      - .dev-docker.env
    stdin_open: true
    tty: true

只需使用這兩個檔案，你就可以執行 docker-compose up 並喚醒你的 docker