removing latin encoding, adding usage notes

generic_loader/load_folder.py

@@ -47,6 +47,7 @@ USAGE
 ::
 
     python load_folder.py --config folder_config.yaml [--dry-run] [--fail-fast]
+                          [--dbcreds]
 
 Flags:
     --config PATH   Required. Path to the YAML config above.
@@ -56,6 +57,11 @@ Flags:
     --fail-fast     Abort the whole run on the first cluster failure.
                     Default is to log the failure, roll that cluster back,
                     and keep going.
+    --dbcreds       Prompt interactively for the database username and
+                    password instead of reading ``PGUSER`` / ``PGPASSWORD``
+                    from the environment or ``.env`` file. The password
+                    prompt does not echo. Has no effect with ``--dry-run``
+                    (no connection is opened).
 
 Exit codes:
     0 - every cluster loaded successfully (or dry-run completed)

generic_loader/load_sas.py

@@ -57,6 +57,7 @@ the vars) before calling :func:`connect`.
 ::
 
     python load_sas.py --config path/to/config.yaml [--validate] [--dry-run]
+                       [--dbcreds]
 
 Flags:
     --config PATH   Required. Path to the YAML config above.
@@ -66,6 +67,11 @@ Flags:
                     ``--dry-run``.
     --dry-run       Print the inferred ``CREATE TABLE`` SQL and stop. The
                     database is never touched (no connection is opened).
+    --dbcreds       Prompt interactively for the database username and
+                    password instead of reading ``PGUSER`` / ``PGPASSWORD``
+                    from the environment or ``.env`` file. The password
+                    prompt does not echo. Has no effect with ``--dry-run``
+                    (no connection is opened).
 
 Exit codes:
     0 - success (load completed, or dry-run/validate passed)
@@ -85,6 +91,9 @@ Typical invocations::
     # Actually load the data.
     python load_sas.py --config sample_config.yaml
 
+    # Load the data, prompting for credentials instead of using .env.
+    python load_sas.py --config sample_config.yaml --dbcreds
+
 4. Expected-types manifest (``--validate``)
 -------------------------------------------
 ``--validate`` looks for a JSON file named ``<sas-stem>.expected.json`` next
@@ -403,7 +412,7 @@ def _sas_reader(path: Path) -> Tuple[Any, Dict[str, Any]]:
     if suffix in (".xpt", ".xport"):
         return pyreadstat.read_xport, {}
     if suffix == ".sas7bdat":
-        return pyreadstat.read_sas7bdat, {"encoding": "latin-1"}
+        return pyreadstat.read_sas7bdat, {}
     raise ValueError(f"Unsupported SAS file extension: {suffix}")