Puppet custom type

自定义类型可以存在于任何模块中，存放在模块子目录 lib/puppet/type 下，以类型名称来命名，在该文件中进行类型的声明，如 lib/puppet/type/<TYPE NAME>.rb。

示例

Types are created by calling the newtype method on the Puppet::Type class.

示例1

# lib/puppet/type/gitrepo.rb
Puppet::Type.newtype(:gitrepo) do
  @doc = "Manages Git repos"
  ensurable
  newparam(:source) do
    desc "Git source URL for the repo"
    isnamevar
  end
  newparam(:path) do
    desc "Path where the repo should be created"
    validate do | value|
      basepath = File.dirname(value)
      unless File.directory?(basepath)
        raise ArgumentError , "The path %s doesn' t exist" % basepath
    end
  end
end

The name of the type is the only required argument to newtype. The name must be a Ruby symbol, and the name of the file containing the type must match the type’s name.
The newtype method also requires a block of code, specified with either curly braces ({ ... }) or the do ... end syntax. This code block will implement the type, and contains all of the properties and parameters. The block will not be passed any arguments.
Puppet::Type.newtype(:gitrepo) 注册一种新类型gitrepo
@doc 文档，用来描述这个类型以及参数的用途
ensurable 给类型添加了 ensure 属性
newparam(:source) 参数 source
Namevar: Every type must have at least one mandatory parameter: the namevar. This parameter will uniquely identify each resource of the type on the target system
isnamevar 声明告知 Puppet source 这个参数是这个类型的名称参数。所以，当声明这个资源的一个实例时，无论给这个资源什么名字，这个名字都会是 source 这个参数的值
newparam(:path) 该类型包含 path 参数
validate 参数校验机制，如果传递不合适的参数，会返回有用的错误信息

示例2

# lib/puppet/type/database.rb
Puppet::Type.newtype(:database) do
  @doc = %q{Creates a new database. Depending
    on the provider, this may create relational
    databases or NoSQL document stores.

    Example:

        database {'mydatabase':
          ensure => present,
          owner  => root,
        }
  }

  ensurable

  newproperty(:owner) do
    desc "The owner of the database."
    validate do |value|
      unless value =~ /^\w+/
        raise ArgumentError, "%s is not a valid user name" % value
      end
    end
  end

  newproperty(:enable) do
    newvalue(:true)
    newvalue(:false)
  end

  newproperty(:minute, :array_matching => :all) do # :array_matching defaults to :first
    ...
  end

  newparam(:path) do
    isnamevar
  end
end

:database 是Ruby symbol，符号，名称标签。
ensurable ensure property, this property uses three methods on the provider: create, destroy, and exists?. The last method, somewhat obviously, is a boolean to determine if the resource current exists. If a resource’s ensure property is out of sync, then no other properties will be checked or modified.
ensure property should be the first property, because puppet keeps track of the definition order, and it always checks and fixes properties in the order they are defined.
Regular expressions $: start with, \w: word character; same as [0-9A-Za-z_], +: one or more repetitions of the preceding
Array value: By default, if a property is assigned multiple values in an array:
- It is considered in sync if any of those values matches the current value.
- If none of those values match, the first one will be used when syncing the property.

也可以为这个参数能够接收的所有值指定一个列表:

newparam(:breakfast) do
  newvalues(:bacon, :eggs, :sausages)
end

参考资料

[英]约翰阿伦德尔（John Arundel. Puppet实战手册. Kindle 版本.
https://docs.puppet.com/puppet/3.8/custom_types.html