module Hiera::Backend
Public Class Methods
# File lib/hiera/backend.rb, line 306 def clear! @backends = {} end
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
# File lib/hiera/backend.rb, line 31 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 interpolate_config(dir, scope, nil) end
Finds the path to a datafile based on the Backend#datadir and extension
If the file is not found nil is returned
# File lib/hiera/backend.rb, line 52 def datafile(backend, scope, source, extension) datafile_in(datadir(backend, scope), source, extension) end
@api private
# File lib/hiera/backend.rb, line 57 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 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
# File lib/hiera/backend.rb, line 113 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
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
# File lib/hiera/backend.rb, line 79 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 = interpolate_config(source, scope, override) yield(source) unless source == "" or source =~ /(^\/|\/\/|\/$)/ end end
# File lib/hiera/backend.rb, line 341 def interpolate_config(entry, scope, override) if @config_lookup_context.nil? @config_lookup_context = { :is_interpolate_config => true, :order_override => override, :recurse_guard => Hiera::RecursiveGuard.new } begin Hiera::Interpolate.interpolate(entry, scope, {}, @config_lookup_context) ensure @config_lookup_context = nil end else # Nested call (will happen when interpolate method 'hiera' is used) Hiera::Interpolate.interpolate(entry, scope, {}, @config_lookup_context.merge(:order_override => override)) end end
@param key [String] The key to lookup. May be quoted with single or double quotes to avoid subkey traversal on dot characters @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
# File lib/hiera/backend.rb, line 241 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 = Util.split_key(key) { |problem| ArgumentError.new("#{problem} in key: #{key}") } subsegments = nil if segments.size > 1 unless strategy.nil? || strategy == :priority raise ArgumentError, "Resolution type :#{strategy} is illegal when accessing values using dotted keys. Offending key was '#{key}'" end 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 if subsegments.nil? value = backend.lookup(segments[0], scope, order_override, resolution_type, context) elsif backend.respond_to?(:lookup_with_segments) value = backend.lookup_with_segments(segments, scope, order_override, resolution_type, context) else value = backend.lookup(segments[0], scope, order_override, resolution_type, context) value = qualified_lookup(subsegments, value, key) unless subsegments.nil? end 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
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](github.com/danielsdeleo/deep_merge) It uses the compatibility mode [deep_merge](github.com/danielsdeleo/deep_merge#using-deep_merge-in-rails)
:native => Native Hash.merge :deep => Use Hash.deeper_merge :deeper => Use Hash.deeper_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
# File lib/hiera/backend.rb, line 201 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.deeper_merge!(right, options) when :deep,'deep' left.deeper_merge(right, options) else # Native and undefined left.merge(right) end 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
# File lib/hiera/backend.rb, line 149 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
Parse a string like '%{foo}'
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
%{...}
replaced.
@api public
# File lib/hiera/backend.rb, line 141 def parse_string(data, scope, extra_data={}, context={:recurse_guard => nil, :order_override => nil}) Hiera::Interpolate.interpolate(data, scope, extra_data, context) end
# File lib/hiera/backend.rb, line 310 def qualified_lookup(segments, hash, full_key = nil) value = hash segments.each do |segment| throw :no_such_key if value.nil? if segment =~ /^[0-9]+$/ segment = segment.to_i unless value.instance_of?(Array) suffix = full_key.nil? ? '' : " from key '#{full_key}'" raise Exception, "Hiera type mismatch: Got #{value.class.name} when Array was expected to access value using '#{segment}'#{suffix}" end throw :no_such_key unless segment < value.size else unless value.respond_to?(:'[]') && !(value.instance_of?(Array) || value.instance_of?(String)) suffix = full_key.nil? ? '' : " from key '#{full_key}'" raise Exception, "Hiera type mismatch: Got #{value.class.name} when a hash-like object was expected to access value using '#{segment}'#{suffix}" end throw :no_such_key unless value.include?(segment) end value = value[segment] end value end
# File lib/hiera/backend.rb, line 172 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
Private Class Methods
# File lib/hiera/backend.rb, line 335 def find_backend(backend_constant) backend = Backend.const_get(backend_constant).new return backend.method(:lookup).arity == 4 ? Backend1xWrapper.new(backend) : backend end