Support "just in time" loading of records, and add ID fields (#154)

* Deserialize records "just in time" in order to avoid import order issues.

* Add changelog entry

* Typing and formatting fixes

* Typing

* Add id field to record.

* Add more informative error message.

* Tweak the way results are stored.

* Typing and formatting fixes.

---------

Co-authored-by: Emily Rockman <[email protected]>

.changes/unreleased/Under the Hood-20240618-155025.yaml

@@ -0,0 +1,6 @@
+kind: Under the Hood
+body: Deserialize Record objects on a just-in-time basis.
+time: 2024-06-18T15:50:25.985387-04:00
+custom:
+  Author: peterallenwebb
+  Issue: "151"

dbt_common/clients/system.py

@@ -62,7 +62,9 @@ def _include(self) -> bool:
         # Do not record or replay filesystem searches that were performed against
         # files which are actually part of dbt's implementation.
         return (
-            "dbt/include/global_project" not in self.root_path
+            "dbt/include"
+            not in self.root_path  # TODO: This actually obviates the next two checks but is probably too coarse?
+            and "dbt/include/global_project" not in self.root_path
             and "/plugins/postgres/dbt/include/" not in self.root_path
         )
 

dbt_common/record.py

@@ -2,7 +2,7 @@
 external systems during a command invocation, so that the command can be re-run
 later with the recording 'replayed' to dbt.
 
-The rationale for and architecture of this module is described in detail in the
+The rationale for and architecture of this module are described in detail in the
 docs/guides/record_replay.md document in this repository.
 """
 import functools
@@ -12,7 +12,7 @@
 
 from deepdiff import DeepDiff  # type: ignore
 from enum import Enum
-from typing import Any, Dict, List, Mapping, Optional, Type
+from typing import Any, Callable, Dict, List, Mapping, Optional, Type
 
 from dbt_common.context import get_invocation_context
 
@@ -129,10 +129,11 @@ def __init__(
         previous_recording_path: Optional[str] = None,
     ) -> None:
         self.mode = mode
-        self.types = types
+        self.recorded_types = types
         self._records_by_type: Dict[str, List[Record]] = {}
+        self._unprocessed_records_by_type: Dict[str, List[Dict[str, Any]]] = {}
         self._replay_diffs: List["Diff"] = []
-        self.diff: Diff
+        self.diff: Optional[Diff] = None
         self.previous_recording_path = previous_recording_path
         self.current_recording_path = current_recording_path
 
@@ -146,7 +147,7 @@ def __init__(
             )
 
             if self.mode == RecorderMode.REPLAY:
-                self._records_by_type = self.load(self.previous_recording_path)
+                self._unprocessed_records_by_type = self.load(self.previous_recording_path)
 
     @classmethod
     def register_record_type(cls, rec_type) -> Any:
@@ -161,7 +162,14 @@ def add_record(self, record: Record) -> None:
         self._records_by_type[rec_cls_name].append(record)
 
     def pop_matching_record(self, params: Any) -> Optional[Record]:
-        rec_type_name = self._record_name_by_params_name[type(params).__name__]
+        rec_type_name = self._record_name_by_params_name.get(type(params).__name__)
+
+        if rec_type_name is None:
+            raise Exception(
+                f"A record of type {type(params).__name__} was requested, but no such type has been registered."
+            )
+
+        self._ensure_records_processed(rec_type_name)
         records = self._records_by_type[rec_type_name]
         match: Optional[Record] = None
         for rec in records:
@@ -186,39 +194,40 @@ def _to_dict(self) -> Dict:
         return dct
 
     @classmethod
-    def load(cls, file_name: str) -> Dict[str, List[Record]]:
+    def load(cls, file_name: str) -> Dict[str, List[Dict[str, Any]]]:
         with open(file_name) as file:
-            loaded_dct = json.load(file)
+            return json.load(file)
 
-        records_by_type: Dict[str, List[Record]] = {}
+    def _ensure_records_processed(self, record_type_name: str) -> None:
+        if record_type_name in self._records_by_type:
+            return
 
-        for record_type_name in loaded_dct:
-            # TODO: this breaks with QueryRecord on replay since it's
-            # not in common so isn't part of cls._record_cls_by_name yet
-            record_cls = cls._record_cls_by_name[record_type_name]
-            rec_list = []
-            for record_dct in loaded_dct[record_type_name]:
-                rec = record_cls.from_dict(record_dct)
-                rec_list.append(rec)  # type: ignore
-            records_by_type[record_type_name] = rec_list
-        return records_by_type
+        rec_list = []
+        record_cls = self._record_cls_by_name[record_type_name]
+        for record_dct in self._unprocessed_records_by_type[record_type_name]:
+            rec = record_cls.from_dict(record_dct)
+            rec_list.append(rec)  # type: ignore
+        self._records_by_type[record_type_name] = rec_list
 
     def expect_record(self, params: Any) -> Any:
         record = self.pop_matching_record(params)
 
         if record is None:
             raise Exception()
 
+        if record.result is None:
+            return None
+
         result_tuple = dataclasses.astuple(record.result)
         return result_tuple[0] if len(result_tuple) == 1 else result_tuple
 
     def write_diffs(self, diff_file_name) -> None:
-        json.dump(
-            self.diff.calculate_diff(),
-            open(diff_file_name, "w"),
-        )
+        assert self.diff is not None
+        with open(diff_file_name, "w") as f:
+            json.dump(self.diff.calculate_diff(), f)
 
     def print_diffs(self) -> None:
+        assert self.diff is not None
         print(repr(self.diff.calculate_diff()))
 
 
@@ -273,7 +282,12 @@ def get_record_types_from_dict(fp: str) -> List:
     return list(loaded_dct.keys())
 
 
-def record_function(record_type, method=False, tuple_result=False):
+def record_function(
+    record_type,
+    method: bool = False,
+    tuple_result: bool = False,
+    id_field_name: Optional[str] = None,
+) -> Callable:
     def record_function_inner(func_to_record):
         # To avoid runtime overhead and other unpleasantness, we only apply the
         # record/replay decorator if a relevant env var is set.
@@ -291,12 +305,17 @@ def record_replay_wrapper(*args, **kwargs):
             if recorder is None:
                 return func_to_record(*args, **kwargs)
 
-            if recorder.types is not None and record_type.__name__ not in recorder.types:
+            if (
+                recorder.recorded_types is not None
+                and record_type.__name__ not in recorder.recorded_types
+            ):
                 return func_to_record(*args, **kwargs)
 
             # For methods, peel off the 'self' argument before calling the
             # params constructor.
             param_args = args[1:] if method else args
+            if method and id_field_name is not None:
+                param_args = (getattr(args[0], id_field_name),) + param_args
 
             params = record_type.params_cls(*param_args, **kwargs)
 
@@ -313,7 +332,7 @@ def record_replay_wrapper(*args, **kwargs):
             r = func_to_record(*args, **kwargs)
             result = (
                 None
-                if r is None or record_type.result_cls is None
+                if record_type.result_cls is None
                 else record_type.result_cls(*r)
                 if tuple_result
                 else record_type.result_cls(r)