1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
# frozen_string_literal: true
# Digs into a variable with dot notation to get a value from a structure.
#
# **To get the value from a variable** (that may or may not exist), call the function with
# one or two arguments:
#
# * The **first** argument must be a string, and must start with a variable name without leading `$`,
# for example `get('facts')`. The variable name can be followed
# by a _dot notation navigation string_ to dig out a value in the array or hash value
# of the variable.
# * The **optional second** argument can be any type of value and it is used as the
# _default value_ if the function would otherwise return `undef`.
# * An **optional lambda** for error handling taking one `Error` argument.
#
# **Dot notation navigation string** -
# The dot string consists of period `.` separated segments where each
# segment is either the index into an array or the value of a hash key.
# If a wanted key contains a period it must be quoted to avoid it being
# taken as a segment separator. Quoting can be done with either
# single quotes `'` or double quotes `"`. If a segment is
# a decimal number it is converted to an Integer index. This conversion
# can be prevented by quoting the value.
#
# @example Getting the value of a variable
# ```puppet
# getvar('facts') # results in the value of $facts
# ```
#
# @example Navigating into a variable
# ```puppet
# getvar('facts.os.family') # results in the value of $facts['os']['family']
# ```
#
# @example Using a default value
# ```puppet
# $x = [1,2,[{'name' =>'waldo'}]]
# getvar('x.2.1.name', 'not waldo')
# # results in 'not waldo'
# ```
#
# For further examples and how to perform error handling, see the `get()` function
# which this function delegates to after having resolved the variable value.
#
# @since 6.0.0 - the ability to dig into the variable's value with dot notation.
#
Puppet::Functions.create_function(:getvar, Puppet::Functions::InternalFunction) do
dispatch :get_from_navigation do
scope_param
param 'Pattern[/\A(?:::)?(?:[a-z]\w*::)*[a-z_]\w*(?:\.|\Z)/]', :get_string
optional_param 'Any', :default_value
optional_block_param 'Callable[1,1]', :block
end
argument_mismatch :invalid_variable_error do
param 'String', :get_string
optional_param 'Any', :default_value
optional_block_param 'Callable', :block
end
def invalid_variable_error(navigation, default_value = nil, &block)
_("The given string does not start with a valid variable name")
end
# Gets a result from a navigation string starting with $var
#
def get_from_navigation(scope, navigation, default_value = nil, &block)
# asserted to start with a valid variable name - dig out the variable
matches = navigation.match(/^((::)?(\w+::)*\w+)(.*)\z/)
navigation = matches[4]
if navigation[0] == '.'
navigation = navigation[1..]
else
unless navigation.empty?
raise ArgumentError, _("First character after var name in get string must be a '.' - got %{char}") % { char: navigation[0] }
end
end
get_from_var_name(scope, matches[1], navigation, default_value, &block)
end
# Gets a result from a $var name and a navigation string
#
def get_from_var_name(scope, var_string, navigation, default_value = nil, &block)
catch(:undefined_variable) do
return call_function_with_scope(scope, 'get', scope.lookupvar(var_string), navigation, default_value, &block)
end
default_value
end
end
|
