使用Capistrano自动化部署

环境：
Centos 7
Capistrano v3
ruby 2.4.1
rails 5.2.3

Installation

install as Ruby Gem

gem install capistrano

Usage in a Rails project

group :development do
  gem "capistrano", "~> 3.10", require: false
  gem "capistrano-rails", "~> 1.3", require: false
end

bundle install

capistrano-rails

• Asset Pipeline Support
  cap deploy:migrate
• Database Migration Support
  cap deploy:compile_assets

Usage

bundle exec cap install

会生成如下结构。

Capfile
config/deploy.rb
config/deploy/production.rb
config/deploy/staging.rb
lib/capistrano/tasks

Capfile 实际上是ruby文件
主要作用：require ruby module,install_plugin, and

# Load custom tasks from `lib/capistrano/tasks` if you have any defined
Dir.glob("lib/capistrano/tasks/*.rake").each { |r| import r }  

config/deploy.rb
配置capistrano task的变量，定义任务，hooks。

config/deploy/*.rb
定义各部署环境的server和roles,即定义各服务器承担了什么角色或者各角色的服务器。 如config/deploy/production.rb 执行的时候需要
cap production deploy

lib/capistrano/tasks
rake文件 定义capistrano的tasks。

添加Rails master key

Capistrano::Rails 写在README里，但基本是必须步骤。
如本地尚未生成master key 执行rails secret or rake secret

编辑Capfile文件

append :linked_files, "config/master.key"

namespace :deploy do
  namespace :check do
    before :linked_files, :set_master_key do
      on roles(:app), in: :sequence, wait: 10 do
        unless test("[ -f #{shared_path}/config/master.key ]")
          upload! 'config/master.key', "#{shared_path}/config/master.key"
        end
      end
    end
  end
end

migration

Capistrano::Rails Recommendations 提到

set :migration_role, :app
# Defaults to :db role

这样当你的server 承担app role的时候，cap deploy:migrate 会起作用。 或者在config/deploy/your_env.rb roles 里添加db 角色。

其他一些总结的任务

def package_add(*pkgs)
  pkgs.each do |pkg|
    unless test "rpm -qa #{pkg}"
      execute("yum -y install #{pkg}")
    end
  end
end

namespace :rbenv do
    before :update_ruby_build,:dep do
        on roles(:app) do
            execute("yum install -y openssl-devel readline-devel zlib-devel")
        end
    end
end

namespace :puma do
  before :nginx_config,:install do
    on roles(:app) do
      package_add "nginx"
     
      unless test "[ -d /etc/nginx/sites-available ]"
        execute("mkdir -p /etc/nginx/sites-available")
      end
      unless test "[ -d /etc/nginx/sites-enabled ]"
        execute("mkdir -p /etc/nginx/sites-enabled")
      end

    end
  end
end

namespace :bundler do
    before :install,:dep do 
        on roles(:app) do
            package_add "epel-release","yum-utils"
            package_add "postgresql-devel"
            unless test "rpm -qa postgresql12-server"
              execute("yum -y install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm")
              execute("yum-config-manager --enable pgdg12")
              execute("yum -y install postgresql12-server postgresql12")
              execute("/usr/pgsql-12/bin/postgresql-12-setup initdb")
              execute("systemctl enable --now postgresql-12")
              execute("systemctl status postgresql-12")
              execute("firewall-cmd --add-service=postgresql --permanent")
              execute("firewall-cmd --reload")
              # execute("sudo su - postgres;psql -c 'alter user postgres with password \'\'' ")
            end
            package_add "sqlite-devel"
            
            # execute("yum -y install nodejs")
            
        end
    end
end