core: minor helpers for error handling

my/core/__init__.py

@@ -7,3 +7,5 @@ from .common import stat, Stats
 
 from .cfg import make_config
 from .util import __NOT_HPI_MODULE__
+
+from .error import Res, unwrap

my/core/error.py

@@ -108,6 +108,9 @@ def set_error_datetime(e: Exception, dt: datetime) -> None:
     e.args = e.args + (dt,)
     # todo not sure if should return new exception?
 
+def attach_dt(e: Exception, *, dt: datetime) -> Exception:
+    set_error_datetime(e, dt)
+    return e
 
 # todo it might be problematic because might mess with timezones (when it's converted to string, it's converted to a shift)
 def extract_error_datetime(e: Exception) -> Optional[datetime]:

my/core/pandas.py

@@ -51,3 +51,14 @@ def check_dataframe(f: FuncT) -> FuncT:
     return wrapper # type: ignore[return-value]
 
 # todo doctor: could have a suggesion to wrap dataframes with it?? discover by return type?
+
+
+from typing import Dict, Any
+from .error import extract_error_datetime
+def error_to_row(e: Exception, *, dt_col: str='dt') -> Dict[str, Any]:
+    # TODO attach traceback?
+    edt = extract_error_datetime(e)
+    return {
+        'error': str(e),
+        dt_col : edt,
+    }