Give useful error message on common import issue.

This patch addresses #7758 by checking some heuristics on the string
provided for import, and if it looks like a file that wasn't given the
URI "file://" prefix, tell the user. This also updates the docs for
"configure import" to make this requirement more clear.

Author: tarsir

awscli/customizations/configure/importer.py

@@ -19,6 +19,10 @@
 from awscli.customizations.configure.writer import ConfigFileWriter
 
 
+class ConfigureImportError(Exception):
+    pass
+
+
 class ConfigureImportCommand(BasicCommand):
     NAME = 'import'
     DESCRIPTION = (
@@ -36,9 +40,11 @@ class ConfigureImportCommand(BasicCommand):
         {'name': 'csv',
          'required': True,
          'help_text': (
-             'The credentials in CSV format generated by the AWS web console.'
+             'The credentials in CSV format generated by the AWS web console. '
              'The CSV file must contain the "User name", "Access key ID", and '
-             '"Secret access key" headers.'
+             '"Secret access key" headers. '
+             'If passing a CSV file path instead of a CSV-formatted string, '
+             'the "file://" prefix is required.'
          ),
          'cli_type_name': 'string'},
         {'name': 'skip-invalid',
@@ -57,6 +63,9 @@ class ConfigureImportCommand(BasicCommand):
          'default': '',
          'cli_type_name': 'string'},
     ]
+    _POSSIBLE_FILE_ARGUMENT = (
+        'You may be passing a file to import without the "file://" prefix'
+    )
 
     def __init__(self, session, csv_parser=None, importer=None,
                  out_stream=None):
@@ -89,9 +98,21 @@ def _import_csv(self, contents):
         import_msg = 'Successfully imported %s profile(s)\n' % len(credentials)
         uni_print(import_msg, out_file=self._out_stream)
 
+    def _check_possible_filepath(self, csv):
+        """
+        Check if the data 1) wouldn't be imported as anything useful, and 2)
+        looks like it could be a file.
+        """
+        line_count = csv.count('\n')
+        if line_count <= 1:
+            comma_count = csv.count(',')
+            if comma_count == 0 and os.path.isfile(csv):
+                raise ConfigureImportError(self._POSSIBLE_FILE_ARGUMENT)
+
     def _run_main(self, parsed_args, parsed_globals):
         self._csv_parser.strict = not parsed_args.skip_invalid
         self._profile_prefix = parsed_args.profile_prefix
+        self._check_possible_filepath(parsed_args.csv)
         self._import_csv(parsed_args.csv)
         return 0
 

tests/unit/customizations/configure/test_importer.py

@@ -22,6 +22,7 @@
     ConfigureImportCommand,
     CSVCredentialParser,
     CredentialParserError,
+    ConfigureImportError,
 )
 from awscli.customizations.configure.writer import ConfigFileWriter
 
@@ -88,6 +89,10 @@ def test_import_downloaded_bad_headers(self):
         with self.assertRaises(CredentialParserError):
             self.import_command(args=['--csv', content], parsed_globals=None)
 
+    def test_import_fails_if_suspected_file_without_uri_prefix(self):
+        with self.assertRaises(ConfigureImportError):
+            self.import_command(args=['--csv', './README.rst'], parsed_globals=None)
+
 
 class TestCSVCredentialParser(unittest.TestCase):
     def setUp(self):