Set the minimum logging level via --debug option

Without --debug, both cbi.log and the terminal are restricted to displaying
only info, warning and error messages.

With --debug, cbi.log includes debug messages by default, but the terminal
displays debug messages only with sufficient --verbose flags.

Signed-off-by: John Pennycook <john.pennycook@intel.com>

Author: Pennycook

codebasin/__main__.py

@@ -89,6 +89,14 @@ def _main():
         default=0,
         help=_help_string("Decrease verbosity level."),
     )
+    parser.add_argument(
+        "--debug",
+        dest="debug",
+        action="store_const",
+        default=False,
+        const=True,
+        help=_help_string("Enable debug output."),
+    )
     parser.add_argument(
         "-R",
         "--report",
@@ -152,13 +160,17 @@ def _main():
     # Configure logging such that:
     # - All messages are written to a log file
     # - Only errors are written to the terminal by default
-    # - Messages written to terminal are based on -q and -v flags
+    # - Messages written to terminal are based on -q, -v and --debug flags
     # - Meta-warnings and statistics are generated by a WarningAggregator
     aggregator = WarningAggregator()
     log.setLevel(logging.DEBUG)
+    if args.debug:
+        min_log_level = logging.DEBUG
+    else:
+        min_log_level = logging.INFO
 
     file_handler = logging.FileHandler("cbi.log", mode="w")
-    file_handler.setLevel(logging.INFO)
+    file_handler.setLevel(min_log_level)
     file_handler.setFormatter(Formatter())
     file_handler.addFilter(aggregator)
     log.addHandler(file_handler)
@@ -169,7 +181,7 @@ def _main():
     print(f"Log file created at {log_path}")
 
     log_level = max(
-        logging.INFO,
+        min_log_level,
         logging.ERROR - 10 * (args.verbose - args.quiet),
     )
     stdout_handler = logging.StreamHandler(sys.stdout)