# This class is the backing implementation of the Puppet function 'lookup'.
# See puppet/functions/lookup.rb for documentation.
#
module Puppet::Pops
module Lookup
LOOKUP_OPTIONS = 'lookup_options'.freeze
GLOBAL = '__global__'.freeze
# Performs a lookup in the configured scopes and optionally merges the default.
#
# This is a backing function and all parameters are assumed to have been type checked.
# See puppet/functions/lookup.rb for full documentation and all parameter combinations.
#
# @param name [String|Array<String>] The name or names to lookup
# @param type [Types::PAnyType|nil] The expected type of the found value
# @param default_value [Object] The value to use as default when no value is found
# @param has_default [Boolean] Set to _true_ if _default_value_ is included (_nil_ is a valid _default_value_)
# @param merge [MergeStrategy,String,Hash<String,Object>,nil] Merge strategy or hash with strategy and options
# @param lookup_invocation [Invocation] Invocation data containing scope, overrides, and defaults
# @return [Object] The found value
#
def self.lookup(name, value_type, default_value, has_default, merge, lookup_invocation)
names = name.is_a?(Array) ? name : [name]
# find first name that yields a non-nil result and wrap it in a two element array
# with name and value.
not_found = MergeStrategy::NOT_FOUND
override_values = lookup_invocation.override_values
result_with_name = names.reduce([nil, not_found]) do |memo, key|
value = override_values.include?(key) ? assert_type(["Value found for key '%s' in override hash", key], value_type, override_values[key]) : not_found
catch(:no_such_key) { value = search_and_merge(key, lookup_invocation, merge, false) } if value.equal?(not_found)
break [key, assert_type('Found value', value_type, value)] unless value.equal?(not_found)
memo
end
# Use the 'default_values' hash as a last resort if nothing is found
if result_with_name[1].equal?(not_found)
default_values = lookup_invocation.default_values
unless default_values.empty?
result_with_name = names.reduce(result_with_name) do |memo, key|
value = default_values.include?(key) ? assert_type(["Value found for key '%s' in default values hash", key], value_type, default_values[key]) : not_found
memo = [key, value]
break memo unless value.equal?(not_found)
memo
end
end
end
answer = result_with_name[1]
if answer.equal?(not_found)
if block_given?
answer = assert_type('Value returned from default block', value_type, yield(name))
elsif has_default
answer = assert_type('Default value', value_type, default_value)
else
lookup_invocation.emit_debug_info(debug_preamble(names)) if Puppet[:debug]
fail_lookup(names)
end
end
lookup_invocation.emit_debug_info(debug_preamble(names)) if Puppet[:debug]
answer
end
# @api private
def self.debug_preamble(names)
if names.size == 1
names = "'#{names[0]}'"
else
names = names.map { |n| "'#{n}'" }.join(', ')
end
"Lookup of #{names}"
end
# @api private
def self.search_and_merge(name, lookup_invocation, merge, apl = true)
answer = lookup_invocation.lookup_adapter.lookup(name, lookup_invocation, merge)
lookup_invocation.emit_debug_info("Automatic Parameter Lookup of '#{name}'") if apl && Puppet[:debug]
answer
end
def self.assert_type(subject, type, value)
type ? Types::TypeAsserter.assert_instance_of(subject, type, value) : value
end
private_class_method :assert_type
def self.fail_lookup(names)
raise Puppet::DataBinding::LookupError,
n_("Function lookup() did not find a value for the name '%{name}'",
"Function lookup() did not find a value for any of the names [%{name_list}]", names.size
) % { name: names[0], name_list: names.map { |n| "'#{n}'" }.join(', ') }
end
private_class_method :fail_lookup
end
end
require_relative 'lookup/lookup_adapter'
require_relative 'lookup/key_recorder'
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