Chef

# metadata.rb
name 'mycookbook'
maintainer 'Your Name'
maintainer_email 'you@example.com'
license 'Apache-2.0'
description 'Installs and configures my application'
version '1.2.3'

# Chef 版本要求
chef_version '>= 16.0'

# 依赖其他 Cookbooks
depends 'nginx', '~> 10.0'
depends 'mysql', '>= 8.0'
depends 'apt', '~> 7.4'

# 支持的操作系统
supports 'ubuntu', '>= 18.04'
supports 'centos', '>= 7.0'
supports 'debian', '>= 10'

# 提供的 Recipes
provides 'mycookbook::default'
provides 'mycookbook::webserver'

# 源代码仓库
source_url 'https://github.com/yourorg/mycookbook'
issues_url 'https://github.com/yourorg/mycookbook/issues'

# 隐私声明
privacy true

depends 'nginx'              # 任意版本
depends 'nginx', '= 10.0.0'  # 精确版本
depends 'nginx', '>= 10.0'   # 大于等于
depends 'nginx', '~> 10.0'   # 悲观版本锁定（>= 10.0, < 11.0）
depends 'nginx', '>= 10.0', '< 12.0'  # 范围

# Berksfile
source 'https://supermarket.chef.io'

# 当前 Cookbook 的元数据
metadata

# 额外的依赖（不在 metadata.rb 中声明）
cookbook 'build-essential', '~> 8.2'

# 从 Git 仓库安装
cookbook 'custom-nginx',
  git: 'https://github.com/yourorg/custom-nginx.git',
  branch: 'master'

# 从本地路径安装
cookbook 'internal-tools',
  path: '../internal-tools'

# 指定特定版本
cookbook 'java', '~> 8.5.0'

# 分组依赖（用于不同环境）
group :integration do
  cookbook 'test-helper'
end

# Berksfile.lock（自动生成，不要手动编辑）
DEPENDENCIES
  mycookbook
    path: .
    metadata: true
  nginx (~> 10.0)

GRAPH
  mycookbook (1.2.3)
    nginx (~> 10.0)
  nginx (10.1.0)
    apt (>= 7.0)
  apt (7.4.0)

# attributes/default.rb

# 基本属性定义
default['mycookbook']['version'] = '1.0.0'
default['mycookbook']['user'] = 'appuser'
default['mycookbook']['group'] = 'appgroup'

# 嵌套属性
default['mycookbook']['config']['port'] = 8080
default['mycookbook']['config']['host'] = '0.0.0.0'
default['mycookbook']['config']['workers'] = 4

# 数组属性
default['mycookbook']['packages'] = %w(git curl vim)
default['mycookbook']['allowed_ips'] = ['10.0.0.0/8', '192.168.0.0/16']

# Hash 属性
default['mycookbook']['database'] = {
  'host' => 'localhost',
  'port' => 3306,
  'name' => 'myapp',
  'user' => 'dbuser',
  'password' => 'secret'
}

# 基于平台的条件属性
case node['platform']
when 'ubuntu', 'debian'
  default['mycookbook']['package_name'] = 'myapp'
  default['mycookbook']['service_name'] = 'myapp'
when 'centos', 'redhat'
  default['mycookbook']['package_name'] = 'myapp-el'
  default['mycookbook']['service_name'] = 'myapp-service'
end

# 基于平台版本
if node['platform_version'].to_f >= 20.04
  default['mycookbook']['use_systemd'] = true
else
  default['mycookbook']['use_systemd'] = false
end

# 计算属性（基于其他属性）
default['mycookbook']['install_dir'] = "/opt/#{node['mycookbook']['version']}"
default['mycookbook']['config_file'] = "#{node['mycookbook']['install_dir']}/config.yml"

# 使用 normal 级别（持久化）
normal['mycookbook']['node_id'] = SecureRandom.uuid

# 使用 override 级别（覆盖默认值）
override['mycookbook']['debug'] = true if node.chef_environment == 'development'

# recipes/default.rb

# 读取属性
app_user = node['mycookbook']['user']
app_port = node['mycookbook']['config']['port']

# 使用属性
user app_user do
  system true
  shell '/bin/false'
  home '/opt/myapp'
end

directory '/opt/myapp' do
  owner app_user
  group node['mycookbook']['group']
  mode '0755'
  action :create
end

# 使用数组属性
node['mycookbook']['packages'].each do |pkg|
  package pkg do
    action :install
  end
end

# 使用 Hash 属性
template '/etc/myapp/database.yml' do
  source 'database.yml.erb'
  variables(
    database: node['mycookbook']['database']
  )
  mode '0600'
end

# 修改属性（仅在当前运行中有效）
node.default['mycookbook']['runtime_value'] = 'computed'

# 使用计算属性
file node['mycookbook']['config_file'] do
  content "port: #{node['mycookbook']['config']['port']}"
  action :create
end

# attributes/default.rb - 基础属性
default['mycookbook']['version'] = '1.0.0'

# attributes/database.rb - 数据库相关属性
default['mycookbook']['database']['host'] = 'localhost'
default['mycookbook']['database']['port'] = 3306

# attributes/web.rb - Web 服务器属性
default['mycookbook']['web']['port'] = 80
default['mycookbook']['web']['ssl_port'] = 443

# roles/webserver.rb
name 'webserver'
description 'Web server role'

default_attributes(
  'mycookbook' => {
    'config' => {
      'port' => 80
    }
  }
)

override_attributes(
  'mycookbook' => {
    'config' => {
      'workers' => 8  # 覆盖默认的 4
    }
  }
)

run_list(
  'recipe[mycookbook::default]',
  'recipe[nginx::default]'
)

# environments/production.rb
name 'production'
description 'Production environment'

default_attributes(
  'mycookbook' => {
    'database' => {
      'host' => 'db.prod.example.com'
    }
  }
)

override_attributes(
  'mycookbook' => {
    'debug' => false
  }
)

package 'name' do
  package_name      String, Array  # 包名（默认为资源名称）
  version           String          # 版本号
  options           String, Array   # 传递给包管理器的额外选项
  source            String          # 本地包文件路径
  timeout           Integer         # 超时时间（秒）
  action            Symbol          # 默认 :install
end

# 基本安装
package 'nginx'

# 指定版本
package 'nginx' do
  version '1.18.0-1ubuntu1'
  action :install
end

# 多包安装
package %w(git curl vim wget)

# 使用平台特定包管理器
yum_package 'httpd' do
  flush_cache [:before]  # YUM 特定功能
  action :install
end

# 安装本地 RPM 包
rpm_package 'custom-app' do
  source '/tmp/custom-app-1.0.0.rpm'
  action :install
end

# DNF 包安装（RHEL 8+）
dnf_package 'postgresql' do
  version '12.5'
  action :install
end

# APT 包安装
apt_package 'nginx' do
  default_release 'buster-backports'  # APT 特定功能
  action :install
end

# 条件安装
package 'apache2' do
  only_if { node['platform_family'] == 'debian' }
end

# 带通知的安装
package 'nginx' do
  notifies :restart, 'service[nginx]', :delayed
end

service 'name' do
  service_name       String         # 服务名称（默认为资源名称）
  pattern            String         # 用于搜索进程的模式
  start_command      String         # 自定义启动命令
  stop_command       String         # 自定义停止命令
  restart_command    String         # 自定义重启命令
  reload_command     String         # 自定义重载命令
  status_command     String         # 自定义状态检查命令
  supports           Hash           # 服务支持的操作
  timeout            Integer        # 超时时间（秒）
  action             Symbol         # 默认 :nothing
end

# 基本服务管理
service 'nginx' do
  action [:enable, :start]
end

# 完整配置
service 'nginx' do
  service_name 'nginx'
  supports status: true, restart: true, reload: true
  action [:enable, :start]
  subscribes :reload, 'template[/etc/nginx/nginx.conf]', :delayed
end

# 自定义命令
service 'myapp' do
  start_command '/opt/myapp/bin/start.sh'
  stop_command '/opt/myapp/bin/stop.sh'
  status_command '/opt/myapp/bin/status.sh'
  pattern 'myapp'
  action [:enable, :start]
end

# 条件重启
service 'apache2' do
  action :restart
  only_if { ::File.exist?('/etc/apache2/apache2.conf') }
end

systemd_unit 'name' do
  content              String, Hash   # 单元文件内容
  unit_name            String         # 单元名称（默认为资源名称）
  user                 String         # 用户级单元（非系统级）
  triggers_reload      true, false    # 是否触发 systemd 重载，默认 true
  verify               true, false    # 是否验证单元文件，默认 true
  action               Symbol         # 默认 :nothing
end

# 使用 Hash 创建 service 单元
systemd_unit 'myapp.service' do
  content({
    Unit: {
      Description: 'My Application Service',
      After: 'network.target'
    },
    Service: {
      Type: 'simple',
      User: 'appuser',
      WorkingDirectory: '/opt/myapp',
      ExecStart: '/opt/myapp/bin/start.sh',
      ExecStop: '/opt/myapp/bin/stop.sh',
      Restart: 'on-failure',
      RestartSec: '10s'
    },
    Install: {
      WantedBy: 'multi-user.target'
    }
  })
  action [:create, :enable, :start]
end

# 使用字符串创建 service 单元
systemd_unit 'custom-app.service' do
  content <<~UNIT
    [Unit]
    Description=Custom Application
    After=network.target

    [Service]
    Type=forking
    ExecStart=/usr/bin/custom-app --daemon
    PIDFile=/var/run/custom-app.pid

    [Install]
    WantedBy=multi-user.target
  UNIT
  action [:create, :enable, :start]
end

# 创建 timer 单元（定时任务）
systemd_unit 'backup.timer' do
  content({
    Unit: {
      Description: 'Daily Backup Timer'
    },
    Timer: {
      OnCalendar: 'daily',
      Persistent: true
    },
    Install: {
      WantedBy: 'timers.target'
    }
  })
  action [:create, :enable, :start]
end

# 对应的 service 单元
systemd_unit 'backup.service' do
  content({
    Unit: {
      Description: 'Backup Service'
    },
    Service: {
      Type: 'oneshot',
      ExecStart: '/usr/local/bin/backup.sh'
    }
  })
  action :create
end

# 创建用户级单元
systemd_unit 'user-app.service' do
  user 'john'
  content({
    Unit: {
      Description: 'User Application'
    },
    Service: {
      ExecStart: '/home/john/bin/app'
    },
    Install: {
      WantedBy: 'default.target'
    }
  })
  action [:create, :enable, :start]
end

# 屏蔽服务（防止被启动）
systemd_unit 'unwanted.service' do
  action :mask
end

# 删除单元文件
systemd_unit 'old-service.service' do
  action [:stop, :disable, :delete]
end

file 'name' do
  path              String         # 文件路径（默认为资源名称）
  content           String         # 文件内容
  owner             String, Integer # 文件所有者
  group             String, Integer # 文件组
  mode              String, Integer # 文件权限（八进制）
  backup            Integer, false  # 备份版本数，默认 5
  checksum          String         # SHA-256 校验和
  force_unlink      true, false    # 删除前先取消链接
  manage_symlink_source true, false # 是否管理符号链接源
  verify            String, Block  # 验证命令或代码块
  action            Symbol         # 默认 :create
end

# 创建文件
file '/etc/motd' do
  content 'Welcome to my server!'
  mode '0644'
  owner 'root'
  group 'root'
  action :create
end

# 使用 lazy 动态生成内容
file '/etc/app/config.txt' do
  content lazy {
    "Hostname: #{node['hostname']}\n" \
    "IP: #{node['ipaddress']}\n" \
    "Generated at: #{Time.now}"
  }
  mode '0644'
  action :create
end

# 删除文件
file '/tmp/oldfile' do
  action :delete
  only_if { ::File.exist?('/tmp/oldfile') }
end

# 修改文件权限
file '/var/log/app.log' do
  mode '0644'
  owner 'appuser'
  group 'appgroup'
  action :touch
end

# 带验证的文件
file '/etc/nginx/nginx.conf' do
  content 'user nginx; worker_processes 4;'
  mode '0644'
  verify 'nginx -t -c %{file}'
  notifies :reload, 'service[nginx]', :delayed
end

# 带备份的文件修改
file '/etc/important.conf' do
  content 'new configuration'
  backup 10  # 保留 10 个备份版本
  action :create
end

template 'name' do
  path              String         # 目标文件路径（默认为资源名称）
  source            String         # 模板文件名（默认为 "name.erb"）
  variables         Hash           # 传递给模板的变量
  cookbook          String         # 模板所在的 Cookbook
  local             true, false    # 是否使用本地模板文件
  owner             String, Integer # 文件所有者
  group             String, Integer # 文件组
  mode              String, Integer # 文件权限
  backup            Integer, false  # 备份版本数
  helpers           Module         # 辅助方法模块
  verify            String, Block  # 验证命令
  action            Symbol         # 默认 :create
end

# 基本模板使用
template '/etc/nginx/nginx.conf' do
  source 'nginx.conf.erb'
  variables(
    worker_processes: node['cpu']['total'],
    worker_connections: 1024
  )
  mode '0644'
  owner 'root'
  group 'root'
  action :create
  notifies :reload, 'service[nginx]', :delayed
end

# 使用 lazy 动态变量
template '/etc/myapp/config.yml' do
  source 'config.yml.erb'
  variables lazy {
    {
      db_host: node['myapp']['db_host'],
      db_port: node['myapp']['db_port'],
      timestamp: Time.now.to_i
    }
  }
  action :create
end

# 从其他 Cookbook 使用模板
template '/etc/app/config.conf' do
  source 'app_config.erb'
  cookbook 'shared-templates'
  variables(
    app_name: 'myapp',
    app_port: 8080
  )
end

# 使用平台特定模板
# Chef 会按顺序查找：
# templates/ubuntu-20.04/app.conf.erb
# templates/ubuntu/app.conf.erb
# templates/default/app.conf.erb
template '/etc/app/app.conf' do
  source 'app.conf.erb'
  action :create
end

# 带验证的模板
template '/etc/apache2/apache2.conf' do
  source 'apache2.conf.erb'
  verify 'apachectl -t -f %{file}'
  notifies :restart, 'service[apache2]', :delayed
end

directory 'name' do
  path              String         # 目录路径（默认为资源名称）
  owner             String, Integer # 目录所有者
  group             String, Integer # 目录组
  mode              String, Integer # 目录权限（八进制）
  recursive         true, false    # 是否递归创建/删除，默认 false
  rights            Hash           # Windows 权限设置
  inherits          true, false    # Windows 继承权限
  action            Symbol         # 默认 :create
end

# 创建目录
directory '/var/www/myapp' do
  owner 'www-data'
  group 'www-data'
  mode '0755'
  action :create
end

# 递归创建多级目录
directory '/opt/app/data/uploads' do
  owner 'appuser'
  group 'appuser'
  mode '0755'
  recursive true
  action :create
end

# 删除目录及其内容
directory '/tmp/olddata' do
  recursive true
  action :delete
  only_if { ::Dir.exist?('/tmp/olddata') }
end

# 仅修改目录权限
directory '/var/log/myapp' do
  mode '0750'
  owner 'appuser'
  group 'appgroup'
  action :create
end

# Windows 目录权限设置
directory 'C:/app/data' do
  rights :read, 'Everyone'
  rights :full_control, 'Administrators'
  action :create
end

execute 'name' do
  command           String, Array  # 要执行的命令（默认为资源名称）
  cwd               String         # 工作目录
  user              String         # 执行用户
  group             String         # 执行组
  environment       Hash           # 环境变量
  creates           String         # 如果文件存在则跳过
  returns           Integer, Array # 期望的退出码，默认 0
  timeout           Integer        # 超时时间（秒）
  umask             String, Integer # 文件创建掩码
  live_stream       true, false    # 实时输出到 STDOUT
  input             String         # 传递给命令的输入
  action            Symbol         # 默认 :run
end

# 基本命令执行
execute 'update-package-cache' do
  command 'apt-get update'
  action :run
end

# 使用 creates 保证幂等性
execute 'download-app' do
  command 'wget https://example.com/app.tar.gz -O /tmp/app.tar.gz'
  creates '/tmp/app.tar.gz'
  action :run
end

# 使用 not_if 条件
execute 'download-app-conditional' do
  command 'wget https://example.com/app.tar.gz -O /tmp/app.tar.gz'
  not_if { ::File.exist?('/tmp/app.tar.gz') }
end

# 设置工作目录、用户和环境变量
execute 'compile-app' do
  command './configure && make && make install'
  cwd '/tmp/myapp-source'
  user 'builder'
  group 'builder'
  environment(
    'PATH' => '/usr/local/bin:/usr/bin:/bin',
    'CC' => 'gcc',
    'CFLAGS' => '-O2'
  )
  timeout 3600
  only_if { ::File.exist?('/tmp/myapp-source/configure') }
end

# 允许特定退出码
execute 'optional-migration' do
  command '/opt/app/migrate.sh'
  returns [0, 2]  # 0 = 成功，2 = 已迁移
end

# 使用 lazy 动态命令
execute 'set-hostname' do
  command lazy { "hostnamectl set-hostname #{node['custom_hostname']}" }
  only_if { node['custom_hostname'] }
end

# 实时输出（用于长时间运行的命令）
execute 'long-running-build' do
  command 'make all'
  cwd '/opt/project'
  live_stream true
  timeout 7200
end

# 使用数组形式命令（避免 Shell 注入）
execute 'safe-command' do
  command ['/usr/bin/myapp', '--config', '/etc/myapp.conf']
  action :run
end

# 带输入的命令
execute 'create-user' do
  command 'adduser newuser'
  input "password\npassword\n"
  not_if 'id newuser'
end

cookbook_file 'name' do
  path              String         # 目标文件路径（默认为资源名称）
  source            String         # 源文件名（默认为资源名称）
  cookbook          String         # 文件所在的 Cookbook
  owner             String, Integer # 文件所有者
  group             String, Integer # 文件组
  mode              String, Integer # 文件权限
  backup            Integer, false  # 备份版本数
  checksum          String         # SHA-256 校验和
  verify            String, Block  # 验证命令
  action            Symbol         # 默认 :create
end

# 基本文件分发
cookbook_file '/var/www/html/index.html' do
  source 'index.html'  # 从 files/default/index.html
  mode '0644'
  owner 'www-data'
  group 'www-data'
  action :create
end

# 从子目录分发文件
cookbook_file '/etc/ssl/certs/myapp.crt' do
  source 'ssl/myapp.crt'  # 从 files/default/ssl/myapp.crt
  mode '0644'
  action :create
  notifies :reload, 'service[nginx]', :delayed
end

# 从其他 Cookbook 分发文件
cookbook_file '/usr/local/bin/helper.sh' do
  source 'helper.sh'
  cookbook 'shared-scripts'
  mode '0755'
  owner 'root'
  group 'root'
  action :create
end

# 使用校验和验证文件
cookbook_file '/opt/app/config.json' do
  source 'config.json'
  checksum 'a1b2c3d4e5f6...'  # SHA-256 校验和
  action :create
end

# 平台特定文件
# Chef 会自动选择：
# files/ubuntu-20.04/app.conf
# files/ubuntu/app.conf
# files/default/app.conf
cookbook_file '/etc/app/app.conf' do
  source 'app.conf'
  action :create
end

# 带验证的文件
cookbook_file '/etc/sudoers.d/myapp' do
  source 'sudoers-myapp'
  mode '0440'
  verify 'visudo -c -f %{file}'
  action :create
end

# 备份配置
cookbook_file '/etc/important.conf' do
  source 'important.conf'
  backup 10  # 保留 10 个备份版本
  action :create
end

# 语法：notifies :action, 'resource[name]', :timing

template '/etc/nginx/nginx.conf' do
  source 'nginx.conf.erb'
  action :create
  # 配置文件变化后重启 nginx（延迟到 run 结束）
  notifies :reload, 'service[nginx]', :delayed
  # 也可以立即执行
  # notifies :reload, 'service[nginx]', :immediately
end

# 多个通知
file '/etc/app/config.conf' do
  content 'setting=value'
  action :create
  notifies :restart, 'service[app]', :delayed
  notifies :run, 'execute[clear-cache]', :delayed
end

# 语法：subscribes :action, 'resource[name]', :timing

service 'nginx' do
  action [:enable, :start]
  # 订阅配置文件变化
  subscribes :reload, 'template[/etc/nginx/nginx.conf]', :delayed
end

# 等价于 notifies 的反向写法
template '/etc/nginx/nginx.conf' do
  source 'nginx.conf.erb'
  action :create
end

service 'nginx' do
  action [:enable, :start]
  subscribes :reload, 'template[/etc/nginx/nginx.conf]', :delayed
end

# 问题：节点属性在编译时可能未定义
file '/etc/config' do
  content node['runtime_value']  # 编译时求值，可能为 nil
end

# 解决：使用 lazy 延迟到运行时求值
file '/etc/config' do
  content lazy { node['runtime_value'] }  # 运行时求值
end

# 实际应用场景
package 'mysql-server' do
  version lazy { node['mysql']['version'] }  # 版本可能在其他 recipe 中设置
  action :install
end

# 动态生成内容
template '/etc/app/stats.txt' do
  source 'stats.txt.erb'
  variables lazy {
    {
      total_memory: `free -m | awk '/^Mem:/{print $2}'`.to_i,
      disk_usage: `df -h / | awk 'NR==2{print $5}'`.chomp
    }
  }
end

# only_if - 仅当条件为真时执行
package 'nginx' do
  action :install
  only_if { node['platform_family'] == 'debian' }
end

# 使用 Shell 命令
service 'apache2' do
  action :restart
  only_if 'test -f /etc/apache2/apache2.conf'
end

# not_if - 仅当条件为假时执行
execute 'download-app' do
  command 'wget https://example.com/app.tar.gz'
  not_if { ::File.exist?('/tmp/app.tar.gz') }
end

# 使用 Shell 命令
package 'httpd' do
  action :install
  not_if 'rpm -qa | grep -q httpd'
end

# 复杂条件
directory '/opt/app' do
  action :create
  only_if do
    node['environment'] == 'production' &&
    !::Dir.exist?('/opt/app')
  end
end

# 测试包是否安装
describe package('nginx') do
  it { should be_installed }
end

# 测试服务状态
describe service('nginx') do
  it { should be_installed }
  it { should be_enabled }
  it { should be_running }
end

# 测试文件存在和内容
describe file('/etc/nginx/nginx.conf') do
  it { should exist }
  it { should be_file }
  it { should be_owned_by 'root' }
  its('mode') { should cmp '0644' }
  its('content') { should match /worker_processes/ }
end

# 测试目录
describe directory('/var/www/myapp') do
  it { should exist }
  it { should be_directory }
  its('owner') { should eq 'www-data' }
  its('mode') { should cmp '0755' }
end

# 测试端口监听
describe port(80) do
  it { should be_listening }
  its('processes') { should include 'nginx' }
end

# 测试 HTTP 请求
describe http('http://localhost') do
  its('status') { should cmp 200 }
  its('body') { should match /Welcome/ }
end

# 测试命令执行结果
describe command('nginx -v') do
  its('exit_status') { should eq 0 }
  its('stderr') { should match /nginx version/ }
end

# 测试用户和组
describe user('www-data') do
  it { should exist }
  its('group') { should eq 'www-data' }
  its('shell') { should eq '/usr/sbin/nologin' }
end

require 'spec_helper'

describe 'mycookbook::default' do
  let(:chef_run) do
    ChefSpec::ServerRunner.new(platform: 'ubuntu', version: '20.04') do |node|
      node.automatic['memory']['total'] = '2048MB'
    end.converge(described_recipe)
  end

  # 测试包安装
  it 'installs nginx package' do
    expect(chef_run).to install_package('nginx')
  end

  # 测试服务配置
  it 'enables and starts nginx service' do
    expect(chef_run).to enable_service('nginx')
    expect(chef_run).to start_service('nginx')
  end

  # 测试模板渲染
  it 'creates nginx configuration' do
    expect(chef_run).to create_template('/etc/nginx/nginx.conf').with(
      owner: 'root',
      group: 'root',
      mode: '0644'
    )
  end

  # 测试通知
  it 'nginx config notifies nginx restart' do
    template = chef_run.template('/etc/nginx/nginx.conf')
    expect(template).to notify('service[nginx]').to(:reload).delayed
  end

  # 测试文件内容
  it 'renders config with correct worker processes' do
    expect(chef_run).to render_file('/etc/nginx/nginx.conf')
      .with_content(/worker_processes 2/)
  end

  # 测试条件执行
  context 'on debian platform' do
    let(:chef_run) do
      ChefSpec::ServerRunner.new(platform: 'debian', version: '10')
        .converge(described_recipe)
    end

    it 'installs apache2' do
      expect(chef_run).to install_package('apache2')
    end
  end
end

# 编译阶段立即评估
file '/tmp/timestamp.txt' do
  content Time.now.to_s  # 编译时评估，所有资源使用相同时间戳
end

# 延迟到执行阶段评估
file '/tmp/timestamp.txt' do
  content lazy { Time.now.to_s }  # 执行时评估，获取准确的执行时间
end

# Recipe 示例
package 'nginx' do
  action :install
end

template '/etc/nginx/nginx.conf' do
  source 'nginx.conf.erb'
  action :create
  # 依赖 nginx 包安装
end

service 'nginx' do
  action [:enable, :start]
  # 依赖配置文件存在
end