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require 'hiera/util'
require 'hiera/interpolate'
begin
require 'deep_merge'
rescue LoadError
end
class Hiera
module Backend
class Backend1xWrapper
def initialize(wrapped)
@wrapped = wrapped
end
def lookup(key, scope, order_override, resolution_type, context)
Hiera.debug("Using Hiera 1.x backend API to access instance of class #{@wrapped.class.name}. Lookup recursion will not be detected")
value = @wrapped.lookup(key, scope, order_override, resolution_type.is_a?(Hash) ? :hash : resolution_type)
# The most likely cause when an old backend returns nil is that the key was not found. In any case, it is
# impossible to know the difference between that and a found nil. The throw here preserves the old behavior.
throw (:no_such_key) if value.nil?
value
end
end
class << self
# Data lives in /var/lib/hiera by default. If a backend
# supplies a datadir in the config it will be used and
# subject to variable expansion based on scope
def datadir(backend, scope)
backend = backend.to_sym
if Config[backend] && Config[backend][:datadir]
dir = Config[backend][:datadir]
else
dir = Hiera::Util.var_dir
end
if !dir.is_a?(String)
raise(Hiera::InvalidConfigurationError,
"datadir for #{backend} cannot be an array")
end
parse_string(dir, scope)
end
# Finds the path to a datafile based on the Backend#datadir
# and extension
#
# If the file is not found nil is returned
def datafile(backend, scope, source, extension)
datafile_in(datadir(backend, scope), source, extension)
end
# @api private
def datafile_in(datadir, source, extension)
file = File.join(datadir, "#{source}.#{extension}")
if File.exist?(file)
file
else
Hiera.debug("Cannot find datafile #{file}, skipping")
nil
end
end
# Constructs a list of data sources to search
#
# If you give it a specific hierarchy it will just use that
# else it will use the global configured one, failing that
# it will just look in the 'common' data source.
#
# An override can be supplied that will be pre-pended to the
# hierarchy.
#
# The source names will be subject to variable expansion based
# on scope
def datasources(scope, override=nil, hierarchy=nil)
if hierarchy
hierarchy = [hierarchy]
elsif Config.include?(:hierarchy)
hierarchy = [Config[:hierarchy]].flatten
else
hierarchy = ["common"]
end
hierarchy.insert(0, override) if override
hierarchy.flatten.map do |source|
source = parse_string(source, scope, {}, :order_override => override)
yield(source) unless source == "" or source =~ /(^\/|\/\/|\/$)/
end
end
# Constructs a list of data files to search
#
# If you give it a specific hierarchy it will just use that
# else it will use the global configured one, failing that
# it will just look in the 'common' data source.
#
# An override can be supplied that will be pre-pended to the
# hierarchy.
#
# The source names will be subject to variable expansion based
# on scope
#
# Only files that exist will be returned. If the file is missing, then
# the block will not receive the file.
#
# @yield [String, String] the source string and the name of the resulting file
# @api public
def datasourcefiles(backend, scope, extension, override=nil, hierarchy=nil)
datadir = Backend.datadir(backend, scope)
Backend.datasources(scope, override, hierarchy) do |source|
Hiera.debug("Looking for data source #{source}")
file = datafile_in(datadir, source, extension)
if file
yield source, file
end
end
end
# Parse a string like <code>'%{foo}'</code> against a supplied
# scope and additional scope. If either scope or
# extra_scope includes the variable 'foo', then it will
# be replaced else an empty string will be placed.
#
# If both scope and extra_data has "foo", then the value in scope
# will be used.
#
# @param data [String] The string to perform substitutions on.
# This will not be modified, instead a new string will be returned.
# @param scope [#[]] The primary source of data for substitutions.
# @param extra_data [#[]] The secondary source of data for substitutions.
# @param context [#[]] Context can include :recurse_guard and :order_override.
# @return [String] A copy of the data with all instances of <code>%{...}</code> replaced.
#
# @api public
def parse_string(data, scope, extra_data={}, context={:recurse_guard => nil, :order_override => nil})
Hiera::Interpolate.interpolate(data, scope, extra_data, context)
end
# Parses a answer received from data files
#
# Ultimately it just pass the data through parse_string but
# it makes some effort to handle arrays of strings as well
def parse_answer(data, scope, extra_data={}, context={:recurse_guard => nil, :order_override => nil})
if data.is_a?(Numeric) or data.is_a?(TrueClass) or data.is_a?(FalseClass)
return data
elsif data.is_a?(String)
return parse_string(data, scope, extra_data, context)
elsif data.is_a?(Hash)
answer = {}
data.each_pair do |key, val|
interpolated_key = parse_string(key, scope, extra_data, context)
answer[interpolated_key] = parse_answer(val, scope, extra_data, context)
end
return answer
elsif data.is_a?(Array)
answer = []
data.each do |item|
answer << parse_answer(item, scope, extra_data, context)
end
return answer
end
end
def resolve_answer(answer, resolution_type)
case resolution_type
when :array
[answer].flatten.uniq.compact
when :hash
answer # Hash structure should be preserved
else
answer
end
end
# Merges two hashes answers with the given or configured merge behavior. Behavior can be given
# by passing _resolution_type_ as a Hash
#
# :merge_behavior: {:native|:deep|:deeper}
#
# Deep merge options use the Hash utility function provided by [deep_merge](https://github.com/danielsdeleo/deep_merge)
#
# :native => Native Hash.merge
# :deep => Use Hash.deep_merge
# :deeper => Use Hash.deep_merge!
#
# @param left [Hash] left side of the merge
# @param right [Hash] right side of the merge
# @param resolution_type [String,Hash] The merge type, or if hash, the merge behavior and options
# @return [Hash] The merged result
# @see Hiera#lookup
#
def merge_answer(left,right,resolution_type=nil)
behavior, options =
if resolution_type.is_a?(Hash)
merge = resolution_type.clone
[merge.delete(:behavior), merge]
else
[Config[:merge_behavior], Config[:deep_merge_options] || {}]
end
case behavior
when :deeper,'deeper'
left.deep_merge!(right, options)
when :deep,'deep'
left.deep_merge(right, options)
else # Native and undefined
left.merge(right)
end
end
# Calls out to all configured backends in the order they
# were specified. The first one to answer will win.
#
# This lets you declare multiple backends, a possible
# use case might be in Puppet where a Puppet module declares
# default data using in-module data while users can override
# using JSON/YAML etc. By layering the backends and putting
# the Puppet one last you can override module author data
# easily.
#
# Backend instances are cached so if you need to connect to any
# databases then do so in your constructor, future calls to your
# backend will not create new instances
# @param key [String] The key to lookup
# @param scope [#[]] The primary source of data for substitutions.
# @param order_override [#[],nil] An override that will be pre-pended to the hierarchy definition.
# @param resolution_type [Symbol,Hash,nil] One of :hash, :array,:priority or a Hash with deep merge behavior and options
# @param context [#[]] Context used for internal processing
# @return [Object] The value that corresponds to the given key or nil if no such value cannot be found
#
def lookup(key, default, scope, order_override, resolution_type, context = {:recurse_guard => nil})
@backends ||= {}
answer = nil
# order_override is kept as an explicit argument for backwards compatibility, but should be specified
# in the context for internal handling.
context ||= {}
order_override ||= context[:order_override]
context[:order_override] ||= order_override
strategy = resolution_type.is_a?(Hash) ? :hash : resolution_type
segments = key.split('.')
subsegments = nil
if segments.size > 1
raise ArgumentError, "Resolution type :#{strategy} is illegal when doing segmented key lookups" unless strategy.nil? || strategy == :priority
subsegments = segments.drop(1)
end
found = false
Config[:backends].each do |backend|
backend_constant = "#{backend.capitalize}_backend"
if constants.include?(backend_constant) || constants.include?(backend_constant.to_sym)
backend = (@backends[backend] ||= find_backend(backend_constant))
found_in_backend = false
new_answer = catch(:no_such_key) do
value = backend.lookup(segments[0], scope, order_override, resolution_type, context)
value = qualified_lookup(subsegments, value) unless subsegments.nil?
found_in_backend = true
value
end
next unless found_in_backend
found = true
case strategy
when :array
raise Exception, "Hiera type mismatch for key '#{key}': expected Array and got #{new_answer.class}" unless new_answer.kind_of? Array or new_answer.kind_of? String
answer ||= []
answer << new_answer
when :hash
raise Exception, "Hiera type mismatch for key '#{key}': expected Hash and got #{new_answer.class}" unless new_answer.kind_of? Hash
answer ||= {}
answer = merge_answer(new_answer, answer, resolution_type)
else
answer = new_answer
break
end
end
end
answer = resolve_answer(answer, strategy) unless answer.nil?
answer = parse_string(default, scope, {}, context) if !found && default.is_a?(String)
return default if !found && answer.nil?
return answer
end
def clear!
@backends = {}
end
def qualified_lookup(segments, hash)
value = hash
segments.each do |segment|
throw :no_such_key if value.nil?
if segment =~ /^[0-9]+$/
segment = segment.to_i
raise Exception, "Hiera type mismatch: Got #{value.class.name} when Array was expected enable lookup using key '#{segment}'" unless value.instance_of?(Array)
throw :no_such_key unless segment < value.size
else
raise Exception, "Hiera type mismatch: Got #{value.class.name} when a non Array object that responds to '[]' was expected to enable lookup using key '#{segment}'" unless value.respond_to?(:'[]') && !value.instance_of?(Array);
throw :no_such_key unless value.include?(segment)
end
value = value[segment]
end
value
end
def find_backend(backend_constant)
backend = Backend.const_get(backend_constant).new
return backend.method(:lookup).arity == 4 ? Backend1xWrapper.new(backend) : backend
end
private :find_backend
end
end
end
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