variables.md

Variables & Data Types

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Variables in Puppet start with $ and are immutable once assigned (no reassignment within the same scope):

# Simple assignment
$greeting = 'Hello, OpenVox!'
$port     = 8080
$enabled  = true

# Using variables
file { '/etc/motd':
  content => "${greeting}\nListening on port ${port}\n",
}

Facts as Variables

System facts are available via the $facts hash:

# Access facts using the $facts hash (preferred)
notify { "Running on ${facts['os']['name']} ${facts['os']['release']['major']}": }

# Check architecture
if $facts['os']['architecture'] == 'x86_64' {
  notify { 'This is a 64-bit system': }
}

Variable Scope

Variables are scoped to the class or defined type they're declared in:

class myapp {
  $config_dir = '/etc/myapp'  # Available within this class

  file { "${config_dir}/app.conf":
    ensure => file,
  }
}

# Access from outside: $myapp::config_dir
# (only if the class has been declared)

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Data Types

Puppet has a rich type system. Here are the types you'll use most:

Type	Examples	Notes
String	'hello', "world ${var}"	Single or double quotes
Integer	42, -7, 0xFF	Whole numbers
Float	3.14, -0.5	Decimal numbers
Boolean	true, false	Note: lowercase!
Array	[1, 'two', true]	Ordered list
Hash	{'key' => 'value'}	Key-value pairs
Undef	undef	No value (like null)
Regexp	/^web\d+/	Regular expression
Sensitive	Sensitive('s3cret')	Redacted in logs

Type Validation in Parameters

class myapp (
  String           $app_name,
  Integer[1, 65535] $port = 8080,
  Boolean          $debug = false,
  Array[String]    $allowed_hosts = ['localhost'],
  Optional[String] $custom_header = undef,
) {
  # Parameters are type-checked at compile time!
}

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_{This document was created with the assistance of AI (Grok, xAI). All technical content has been reviewed and verified by human contributors.}