add diffing

core/dbt/cli/requires.py

@@ -45,6 +45,7 @@
     Recorder,
     RecorderMode,
     get_record_mode_from_env,
+    get_record_types_from_dict,
     get_record_types_from_env,
 )
 from dbt_common.utils import cast_dict_to_dict_of_strings
@@ -111,7 +112,16 @@ def setup_record_replay():
     recorder: Optional[Recorder] = None
     if rec_mode == RecorderMode.REPLAY:
         recording_path = os.environ.get("DBT_RECORDER_FILE_PATH")
-        recorder = Recorder(RecorderMode.REPLAY, types=rec_types, recording_path=recording_path)
+        recorder = Recorder(
+            RecorderMode.REPLAY, types=rec_types, previous_recording_path=recording_path
+        )
+    elif rec_mode == RecorderMode.DIFF:
+        previous_recording_path = os.environ.get("DBT_RECORDER_FILE_PATH")
+        # ensure types match the previous recording
+        types = get_record_types_from_dict(previous_recording_path)
+        recorder = Recorder(
+            RecorderMode.DIFF, types=types, previous_recording_path=previous_recording_path
+        )
     elif rec_mode == RecorderMode.RECORD:
         recorder = Recorder(RecorderMode.RECORD, types=rec_types)
 
@@ -122,7 +132,11 @@ def tear_down_record_replay():
     recorder = get_invocation_context().recorder
     if recorder is not None:
         if recorder.mode == RecorderMode.RECORD:
-            recorder.write("recording.json")
+            recorder.write()
+        if recorder.mode == RecorderMode.DIFF:
+            # write out result of recording to it was be referred to as needed
+            recorder.write()
+            recorder.write_diffs(diff_file_name="diffs.json")
         elif recorder.mode == RecorderMode.REPLAY:
             recorder.write_diffs("replay_diffs.json")