Add custom JSON generation

to_json will print out a more human readable representation of the api
representation. It uses api property names as json key's in order to provide
more useful breadcrumbs and viewing when collapsed.

api/product.rb

@@ -14,6 +14,7 @@
 require 'api/object'
 require 'google/logger'
 require 'compile/core'
+require 'json'
 
 module Api
   # Repesents a product to be managed
@@ -33,6 +34,23 @@ def api_name
       name.downcase
     end
 
+    def to_json(opts = nil)
+      json_out = {}
+
+      instance_variables.each do |v|
+        if v == :@objects
+          json_out['@resources'] = objects.map { |o| [o.name, o] }.to_h
+        elsif instance_variable_get(v) == false || instance_variable_get(v).nil?
+          # ignore false or missing because omitting them cleans up result
+          # and both are the effective defaults of their types
+        else
+          json_out[v] = instance_variable_get(v)
+        end
+      end
+
+      JSON.generate(json_out, opts)
+    end
+
     # The product full name is the "display name" in string form intended for
     # users to read in documentation; "Google Compute Engine", "Cloud Bigtable"
     def product_full_name
@@ -84,6 +102,12 @@ def validate
         check :name, type: String, allowed: ORDER, required: true
       end
 
+      def to_s
+        str = "#{name}: #{base_url}"
+        str += ' (default)' if default
+        str
+      end
+
       def <=>(other)
         ORDER.index(name) <=> ORDER.index(other.name) if other.is_a?(Version)
       end

api/resource.rb

@@ -135,6 +135,21 @@ def validate
       end
     end
 
+    def to_json(opts = nil)
+      # ignore fields that will contain references to parent resources
+      ignored_fields = %i[@__product @__parent @__resource @api_name @collection_url_response]
+      json_out = {}
+
+      instance_variables.each do |v|
+        json_out[v] = instance_variable_get(v) unless ignored_fields.include? v
+      end
+
+      json_out[:@properties] = properties.map { |p| [p.name, p] }.to_h
+      json_out[:@parameters] = parameters.map { |p| [p.name, p] }.to_h
+
+      JSON.generate(json_out, opts)
+    end
+
     def identity
       props = all_user_properties
       if @identity.nil?

api/type.rb

@@ -74,6 +74,29 @@ def validate
       check_conflicts
     end
 
+    def to_json(opts = nil)
+      # ignore fields that will contain references to parent resources and
+      # those which will be added later
+      ignored_fields = %i[@resource @__parent @__resource @api_name]
+      json_out = {}
+
+      instance_variables.each do |v|
+        if v == :@conflicts && instance_variable_get(v).empty?
+          # ignore empty conflict arrays
+        elsif instance_variable_get(v) == false
+          # ignore false booleans as non-existence indicates falsey
+        elsif !ignored_fields.include? v
+          json_out[v] = instance_variable_get(v)
+        end
+      end
+
+      # convert properties to a hash based on name for nested readability
+      json_out[:@properties] = properties&.map { |p| [p.name, p] }.to_h \
+        if respond_to? 'properties'
+
+      JSON.generate(json_out, opts)
+    end
+
     def check_default_value_property
       return if @default_value.nil?