Puppet Function: pick_default

Defined in:
vendor_modules/stdlib/lib/puppet/parser/functions/pick_default.rb
Function type:
Ruby 3.x API

Summary

This function will return the first value in a list of values that is not undefined or an empty string.

Overview

pick_default() ⇒ Any

Typically, this function is used to check for a value in the Puppet Dashboard/Enterprise Console, and failover to a default value like the following:

$real_jenkins_version = pick_default($::jenkins_version, '1.449')

> Note:

The value of $real_jenkins_version will first look for a top-scope variable
called 'jenkins_version' (note that parameters set in the Puppet Dashboard/
Enterprise Console are brought into Puppet as top-scope variables), and,
failing that, will use a default value of 1.449.

Contrary to the pick() function, the pick_default does not fail if
all arguments are empty. This allows pick_default to use an empty value as
default.

Returns:

  • (Any) —

    This function is similar to a coalesce function in SQL in that it will return the first value in a list of values that is not undefined or an empty string If no value is found, it will return the last argument.



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# File 'vendor_modules/stdlib/lib/puppet/parser/functions/pick_default.rb', line 7

newfunction(:pick_default, type: :rvalue, doc: <<-DOC
  @summary
    This function will return the first value in a list of values that is not undefined or an empty string.

  @return
    This function is similar to a coalesce function in SQL in that it will return
    the first value in a list of values that is not undefined or an empty string
    If no value is found, it will return the last argument.

  Typically, this function is used to check for a value in the Puppet
  Dashboard/Enterprise Console, and failover to a default value like the
  following:

    $real_jenkins_version = pick_default($::jenkins_version, '1.449')

  > *Note:*
    The value of $real_jenkins_version will first look for a top-scope variable
    called 'jenkins_version' (note that parameters set in the Puppet Dashboard/
    Enterprise Console are brought into Puppet as top-scope variables), and,
    failing that, will use a default value of 1.449.

    Contrary to the pick() function, the pick_default does not fail if
    all arguments are empty. This allows pick_default to use an empty value as
    default.
  DOC
) do |args|
  raise 'Must receive at least one argument.' if args.empty?
  default = args.last
  args = args[0..-2].compact
  args.delete(:undef)
  args.delete(:undefined)
  args.delete('')
  args << default
  return args[0]
end