Datatype Composition

You can create datatypes right inside the debugger by using the type keyword.

This is accomplished via the type keyword. This is how you define a type alias in puppet, although you might be use to putting the defination in a file instead. What we are going to do is mock something up real quick in the debugger.

Inside the debugger type the following:

  1. type RedhatOSType = Enum['RedHat', 'CentOS', 'OS/2']

The above code declares a new type called RedHatOSType that will validate if the string being checked is one of the enum types specified. Go ahead and try this out.

The puppet language has a special operator =~ that allows you to compare the type of variable for equality. Try each of the following commands yourself to get a feel for how this works.

Then you can validate against your new datatype.

  1. 'windows' =~ RedhatOSType
  2. 'redhat' =~ RedhatOSType
  3. 'RedHat' =~ RedhatOSType


12:>> type RedhatOSType = Enum['RedHat', 'CentOS', 'OS/2']
13:>> 'windows' =~ RedhatOSType
 => false
14:>> 'redhat' =~ RedhatOSType
 => false
15:>> 'RedHat' =~ RedhatOSType
 => true

You can also utilize the stdlib type_of function to report what datatype a variable is. Although this may result in ambiguous data types.

2:>> md5('hello').upcase.type_of
 => String

While these is a simple example think about something more complex. Take a look at this example and example2

When datatypes get complex we often only check the basics because we don’t understand them fully. But having a way to easily validate your validation allows you to create a more restrictive datatypes.