feat: Optionally record parameter schema

Author: kgilpin

lib/appmap/agent.rb

@@ -100,5 +100,9 @@ def detect_metadata
       @metadata ||= Metadata.detect.freeze
       Util.deep_dup(@metadata)
     end
+
+    def parameter_schema?
+      ENV['APPMAP_PARAMETER_SCHEMA'] == 'true'
+    end
   end
 end

lib/appmap/event.rb

@@ -60,16 +60,37 @@ def display_string(value)
           final ? value_string : encode_display_string(value_string)
         end
 
-        def object_properties(hash_like)
-          hash = hash_like.to_h
-          hash.keys.map do |key|
-            {
+        def add_schema(param, value, always: false)
+          return unless always || AppMap.parameter_schema?
+
+          if value.blank? || value.is_a?(String)
+            # pass
+          elsif value.is_a?(Enumerable)
+            if value.is_a?(Hash)
+              param[:properties] = object_properties(value)
+            elsif value.respond_to?(:first) && value.first
+              param[:properties] = object_properties(value.first)
+            end
+          elsif value.respond_to?(:as_json)
+            add_schema param, JSON.parse(value.to_json), always: always
+          end
+        end
+
+        def object_properties(hash)
+          hash = hash.attributes if hash.respond_to?(:attributes)
+          hash = hash.to_h if hash.is_a?(Struct)
+
+          return unless hash.respond_to?(:each_with_object)
+          
+          hash.each_with_object([]) do |entry, memo|
+            key, value = entry
+            memo << {
               name: key,
-              class: hash[key].class.name,
+              class: value.class.name,
             }
           end
         rescue
-          nil
+          warn $!
         end
 
         # Heuristic for dynamically defined class whose name can be nil
@@ -221,7 +242,9 @@ def build_from_invocation(defined_class, method, receiver, arguments, event: Met
                 object_id: value.__id__,
                 value: display_string(value),
                 kind: param_type
-              }
+                }.tap do |param|
+                  add_schema param, value
+                end
             end
             event.receiver = {
               class: best_class_name(receiver),
@@ -276,15 +299,17 @@ class MethodReturn < MethodReturnIgnoreValue
       attr_accessor :return_value, :exceptions
 
       class << self
-        def build_from_invocation(parent_id, return_value, exception, elapsed: nil, event: MethodReturn.new)
+        def build_from_invocation(parent_id, return_value, exception, elapsed: nil, event: MethodReturn.new, parameter_schema: false)
           event ||= MethodReturn.new
           event.tap do |_|
             if return_value
               event.return_value = {
                 class: best_class_name(return_value),
                 value: display_string(return_value),
                 object_id: return_value.__id__
-              }
+              }.tap do |param|
+                add_schema param, return_value, always: parameter_schema
+              end
             end
             if exception
               next_exception = exception

lib/appmap/handler.rb

@@ -5,6 +5,8 @@
 module AppMap
   # Specific hook handler classes and general related utilities.
   module Handler
+    TEMPLATE_RENDER_VALUE = 'appmap.handler.template.return_value'
+
     # Try to find handler module with a given name.
     #
     # If the module is not loaded, tries to require the appropriate file

lib/appmap/handler/rails/request_handler.rb

@@ -8,8 +8,6 @@ module AppMap
   module Handler
     module Rails
 
-      TEMPLATE_RENDER_VALUE = 'appmap.handler.rails.template.return_value'
-
       module RequestHandler
         class HTTPServerRequest < AppMap::Event::MethodEvent
           attr_accessor :normalized_path_info, :request_method, :path_info, :params, :headers
@@ -77,7 +75,7 @@ def build_from_invocation(parent_id, return_value, elapsed, response, event: HTT
               event ||= HTTPServerResponse.new
               event.status = response.status
               event.headers = response.headers.dup
-              AppMap::Event::MethodReturn.build_from_invocation parent_id, return_value, nil, elapsed: elapsed, event: event
+              AppMap::Event::MethodReturn.build_from_invocation parent_id, return_value, nil, elapsed: elapsed, event: event, parameter_schema: true
             end
           end
 

spec/rails_recording_spec.rb

@@ -54,7 +54,8 @@ def rails_versions
                 'http_server_response' => hash_including(
                   'status_code' => 201,
                   'headers' => hash_including('Content-Type' => 'application/json; charset=utf-8'),
-                )
+                ),
+                'return_value' => hash_including('class' => 'User', 'object_id' => Integer, 'properties' => include({'name' => 'login', 'class' => 'String'})),
               )
             )
           end