code cleanup. better support for nested configs and templates.

1 files changed, 233 insertions, 0 deletions

diff --git a/lib/leap_cli/config/object.rb b/lib/leap_cli/config/object.rb
new file mode 100644
index 0000000..2ef7fe8
--- /dev/null
+++ b/lib/leap_cli/config/object.rb
@@ -0,0 +1,233 @@
+require 'erb'
+require 'json/pure'  # pure ruby implementation is required for our sorted trick to work.
+
+module LeapCli
+  module Config
+    #
+    # This class represents the configuration for a single node, service, or tag.
+    # Also, all the nested hashes are also of this type.
+    #
+    # It is called 'object' because it corresponds to an Object in JSON.
+    #
+    class Object < Hash
+
+      attr_reader :node
+      attr_reader :manager
+      attr_reader :node_list
+      alias :global :manager
+
+      def initialize(manager=nil, node=nil)
+        # keep a global pointer around to the config manager. used a lot in the eval strings and templates
+        # (which are evaluated in the context of Config::Object)
+        @manager = manager
+
+        # an object that is a node as @node equal to self, otherwise all the child objects point back to the top level node.
+        @node = node || self
+
+        # this is only used by Config::Objects that correspond to services or tags.
+        @node_list = Config::ObjectList.new
+      end
+
+      ##
+      ## FETCHING VALUES
+      ##
+
+      #
+      # like a normal hash [], except:
+      # * lazily eval dynamic values when we encounter them.
+      # * support for nested hashes (e.g. ['a.b'] is the same as ['a']['b'])
+      #
+      def [](key)
+        get(key)
+      end
+
+      #
+      # make hash addressable like an object (e.g. obj['name'] available as obj.name)
+      #
+      def method_missing(method, *args, &block)
+        get!(method)
+      end
+
+      def get(key)
+        begin
+          get!(key)
+        rescue NoMethodError
+          nil
+        end
+      end
+
+      def get!(key)
+        key = key.to_s
+        if key =~ /\./
+          keys = key.split('.')
+          value = get!(keys.first)
+          if value.is_a? Config::Object
+            value.get!(keys[1..-1])
+          else
+            value
+          end
+        elsif self.has_key?(key)
+          evaluate_value(key)
+        elsif @node != self
+          @node.get!(key)
+        else
+          raise NoMethodError.new(key, "No method '#{key}' for #{self.class}")
+        end
+      end
+
+      ##
+      ## COPYING
+      ##
+
+      #
+      # Make a copy of ourselves, except only including the specified keys.
+      #
+      # Also, the result is flattened to a single hash, so a key of 'a.b' becomes 'a_b'
+      #
+      def pick(*keys)
+        keys.map(&:to_s).inject(Config::Object.new(@manager,@node)) do |hsh, key|
+          value = self.get(key)
+          if value
+            hsh[key.gsub('.','_')] = value
+          end
+          hsh
+        end
+      end
+
+      #
+      # a deep (recursive) merge with another Config::Object.
+      #
+      def deep_merge!(object)
+        object.each do |key,new_value|
+          old_value = self[key]
+          if old_value.is_a?(Hash) || new_value.is_a?(Hash)
+            # merge hashes
+            value = Config::Object.new(@manager, @node)
+            old_value.is_a?(Hash) ? value.deep_merge!(old_value) : (value[key] = old_value if old_value.any?)
+            new_value.is_a?(Hash) ? value.deep_merge!(new_value) : (value[key] = new_value if new_value.any?)
+          elsif old_value.is_a?(Array) || new_value.is_a?(Array)
+            # merge arrays
+            value = []
+            old_value.is_a?(Array) ? value += old_value : value << old_value
+            new_value.is_a?(Array) ? value += new_value : value << new_value
+            value.compact!
+          elsif new_value.nil?
+            value = old_value
+          elsif old_value.nil?
+            value = new_value
+          elsif old_value.is_a?(Boolean) && new_value.is_a?(Boolean)
+            value = new_value
+          elsif old_value.class != new_value.class
+            raise 'Type mismatch. Cannot merge %s with %s. Key value is %s, name is %s.' % [old_value.class, new_value.class, key, name]
+          else
+            value = new_value
+          end
+          self[key] = value
+        end
+        self
+      end
+
+      private
+
+      #
+      # fetches the value for the key, evaluating the value as ruby if it begins with '='
+      #
+      def evaluate_value(key)
+        value = fetch(key, nil)
+        if value.is_a? Array
+          value
+        elsif value.nil?
+          nil
+        else
+          if value =~ /^= (.*)$/
+            begin
+              value = eval($1, self.send(:binding))
+              self[key] = value
+            rescue SystemStackError => exc
+              puts "STACK OVERFLOW, BAILING OUT"
+              puts "There must be an eval loop of death (variables with circular dependencies). This is the offending string:"
+              puts
+              puts "    #{$1}"
+              puts
+              raise SystemExit.new()
+            rescue StandardError => exc
+              puts "Eval error in '#{@node.name}'"
+              puts "   string: #{$1}"
+              puts "   error: #{exc.name}"
+            end
+          end
+          value
+        end
+      end
+
+      ##
+      ## MACROS
+      ## these are methods used when eval'ing a value in the .json configuration
+      ##
+
+      #
+      # the list of all the nodes
+      #
+      def nodes
+        global.nodes
+      end
+
+      #
+      # inserts the contents of a file
+      #
+      def file(filename)
+        filepath = Path.find_file(@node.name, filename)
+        if filepath
+          if filepath =~ /\.erb$/
+            ERB.new(File.read(filepath), nil, '%<>').result(binding)
+          else
+            File.read(filepath)
+          end
+        else
+          log0('no such file, "%s"' % filename)
+          ""
+        end
+      end
+
+      #
+      # Output json from ruby objects in such a manner that all the hashes and arrays are output in alphanumeric sorted order.
+      # This is required so that our generated configs don't throw puppet or git for a tizzy fit.
+      #
+      # Beware: some hacky stuff ahead.
+      #
+      # This relies on the pure ruby implementation of JSON.generate (i.e. require 'json/pure')
+      # see https://github.com/flori/json/blob/master/lib/json/pure/generator.rb
+      #
+      # The Oj way that we are not using: Oj.dump(obj, :mode => :compat, :indent => 2)
+      #
+      def generate_json(obj)
+
+        # modify hash and array
+        Hash.class_eval do
+          alias_method :each_without_sort, :each
+          def each(&block)
+            keys.sort {|a,b| a.to_s <=> b.to_s }.each do |key|
+              yield key, self[key]
+            end
+          end
+        end
+        Array.class_eval do
+          alias_method :each_without_sort, :each
+          def each(&block)
+            sort {|a,b| a.to_s <=> b.to_s }.each_without_sort &block
+          end
+        end
+
+        # generate json
+        return_value = JSON.pretty_generate(obj)
+
+        # restore hash and array
+        Hash.class_eval  {alias_method :each, :each_without_sort}
+        Array.class_eval {alias_method :each, :each_without_sort}
+
+        return return_value
+      end
+
+    end # class
+  end # module
+end # module
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