55 lines
1.6 KiB
Ruby
55 lines
1.6 KiB
Ruby
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#
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# dig.rb
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#
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module Puppet::Parser::Functions
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newfunction(:dig, :type => :rvalue, :doc => <<-EOS
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Looks up into a complex structure of arrays and hashes and returns nil
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or the default value if nothing was found.
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Path is an array of keys to be looked up in data argument. The function
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will go down the structure and try to extract the required value.
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$data = {
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'a' => {
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'b' => [
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'b1',
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'b2',
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'b3' ]}}
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$value = dig($data, ['a', 'b', '2'], 'not_found')
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=> $value = 'b3'
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a -> first hash key
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b -> second hash key
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2 -> array index starting with 0
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not_found -> (optional) will be returned if there is no value or the path
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did not match. Defaults to nil.
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In addition to the required "path" argument, "dig" accepts default
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argument. It will be returned if no value was found or a path component is
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missing. And the fourth argument can set a variable path separator.
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EOS
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) do |arguments|
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# Two arguments are required
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raise(Puppet::ParseError, "dig(): Wrong number of arguments " +
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"given (#{arguments.size} for at least 2)") if arguments.size < 2
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data, path, default = *arguments
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if !(data.is_a?(Hash) || data.is_a?(Array))
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raise(Puppet::ParseError, "dig(): first argument must be a hash or an array, " <<
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"given #{data.class.name}")
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end
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unless path.is_a? Array
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raise(Puppet::ParseError, "dig(): second argument must be an array, " <<
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"given #{path.class.name}")
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end
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value = path.reduce(data) { |h, k| (h.is_a?(Hash) || h.is_a?(Array)) ? h[k] : break }
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value.nil? ? default : value
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end
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end
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