Add option for user to enter password

Add the --prompt option for the CLI which will cause the user to be
prompted to enter a password. Any password otherwise specified by
--key, --os-password or an environment variable will be ignored.

The swift client will exit with a warning if the password cannot be
entered without its value being echoed.

Closes-Bug: #1357562
Change-Id: I513647eed460007617f129691069c6fb1bfe62d7

3 files changed, 95 insertions, 3 deletions

diff --git a/doc/source/cli/index.rst b/doc/source/cli/index.rst
index 4aa3bfc..88fafa1 100644
--- a/doc/source/cli/index.rst
+++ b/doc/source/cli/index.rst
@@ -139,6 +139,10 @@ swift optional arguments
   compression should be disabled by default by the
   system SSL library.
 
+``--prompt``
+  Prompt user to enter a password which overrides any password supplied via
+  ``--key``, ``--os-password`` or environment variables.
+
 Authentication
 ~~~~~~~~~~~~~~
 
diff --git a/swiftclient/shell.py b/swiftclient/shell.py
index c15d7cf..e91a16f 100755
--- a/swiftclient/shell.py
+++ b/swiftclient/shell.py
@@ -17,11 +17,13 @@
 from __future__ import print_function, unicode_literals
 
 import argparse
+import getpass
 import io
 import json
 import logging
 import signal
 import socket
+import warnings
 
 from os import environ, walk, _exit as os_exit
 from os.path import isfile, isdir, join
@@ -1410,6 +1412,30 @@ class HelpFormatter(argparse.HelpFormatter):
         return action.dest
 
 
+def prompt_for_password():
+    """
+    Prompt the user for a password.
+
+    :raise SystemExit: if a password cannot be entered without it being echoed
+        to the terminal.
+    :return: the entered password.
+    """
+    with warnings.catch_warnings():
+        warnings.filterwarnings('error', category=getpass.GetPassWarning,
+                                append=True)
+        try:
+            # temporarily set signal handling back to default to avoid user
+            # Ctrl-c leaving terminal in weird state
+            signal.signal(signal.SIGINT, signal.SIG_DFL)
+            return getpass.getpass()
+        except EOFError:
+            return None
+        except getpass.GetPassWarning:
+            exit('Input stream incompatible with --prompt option')
+        finally:
+            signal.signal(signal.SIGINT, immediate_exit)
+
+
 def parse_args(parser, args, enforce_requires=True):
     options, args = parser.parse_known_args(args or ['-h'])
     options = vars(options)
@@ -1435,6 +1461,10 @@ def parse_args(parser, args, enforce_requires=True):
     if args and args[0] == 'tempurl':
         return options, args
 
+    # do this before process_options sets default auth version
+    if enforce_requires and options['prompt']:
+        options['key'] = options['os_password'] = prompt_for_password()
+
     # Massage auth version; build out os_options subdict
     process_options(options)
 
@@ -1506,6 +1536,7 @@ def main(arguments=None):
              [--os-key <client-certificate-key-file>]
              [--no-ssl-compression]
              [--force-auth-retry]
+             [--prompt]
              <subcommand> [--help] [<subcommand options>]
 
 Command-line interface to the OpenStack Swift API.
@@ -1620,6 +1651,12 @@ Examples:
                         default=False,
                         help='Force a re-auth attempt on '
                              'any error other than 401 unauthorized')
+    parser.add_argument('--prompt',
+                        action='store_true', dest='prompt',
+                        default=False,
+                        help='Prompt user to enter a password which overrides '
+                             'any password supplied via --key, --os-password '
+                             'or environment variables.')
 
     os_grp = parser.add_argument_group("OpenStack authentication options")
     os_grp.add_argument('--os-username',
diff --git a/tests/unit/test_shell.py b/tests/unit/test_shell.py
index 110fb01..3db48a4 100644
--- a/tests/unit/test_shell.py
+++ b/tests/unit/test_shell.py
@@ -13,8 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from __future__ import unicode_literals
+
 from genericpath import getmtime
 
+import getpass
 import hashlib
 import json
 import logging
@@ -2283,17 +2285,66 @@ class TestParsing(TestBase):
         os_opts = {"password": "secret",
                    "auth_url": "http://example.com:5000/v3"}
         args = _make_args("stat", opts, os_opts)
-        self.assertRaises(SystemExit, swiftclient.shell.main, args)
+        with self.assertRaises(SystemExit) as cm:
+            swiftclient.shell.main(args)
+        self.assertIn(
+            'Auth version 3 requires either OS_USERNAME or OS_USER_ID',
+            str(cm.exception))
 
         os_opts = {"username": "user",
                    "auth_url": "http://example.com:5000/v3"}
         args = _make_args("stat", opts, os_opts)
-        self.assertRaises(SystemExit, swiftclient.shell.main, args)
+        with self.assertRaises(SystemExit) as cm:
+            swiftclient.shell.main(args)
+        self.assertIn('Auth version 3 requires OS_PASSWORD', str(cm.exception))
 
         os_opts = {"username": "user",
                    "password": "secret"}
         args = _make_args("stat", opts, os_opts)
-        self.assertRaises(SystemExit, swiftclient.shell.main, args)
+        with self.assertRaises(SystemExit) as cm:
+            swiftclient.shell.main(args)
+        self.assertIn('Auth version 3 requires OS_AUTH_URL', str(cm.exception))
+
+    def test_password_prompt(self):
+        def do_test(opts, os_opts, auth_version):
+            args = _make_args("stat", opts, os_opts)
+            result = [None, None]
+            fake_command = self._make_fake_command(result)
+            with mock.patch('swiftclient.shell.st_stat', fake_command):
+                with mock.patch('getpass.getpass',
+                                return_value='input_pwd') as mock_getpass:
+                    swiftclient.shell.main(args)
+            mock_getpass.assert_called_once_with()
+            self.assertEqual('input_pwd', result[0]['key'])
+            self.assertEqual('input_pwd', result[0]['os_password'])
+
+            # ctrl-D
+            with self.assertRaises(SystemExit) as cm:
+                with mock.patch('swiftclient.shell.st_stat', fake_command):
+                    with mock.patch('getpass.getpass',
+                                    side_effect=EOFError) as mock_getpass:
+                        swiftclient.shell.main(args)
+            mock_getpass.assert_called_once_with()
+            self.assertIn(
+                'Auth version %s requires' % auth_version, str(cm.exception))
+
+            # force getpass to think it needs to use raw input
+            with self.assertRaises(SystemExit) as cm:
+                with mock.patch('getpass.getpass', getpass.fallback_getpass):
+                    swiftclient.shell.main(args)
+            self.assertIn(
+                'Input stream incompatible', str(cm.exception))
+
+        opts = {"prompt": None, "user": "bob", "key": "secret",
+                "auth": "http://example.com:8080/auth/v1.0"}
+        do_test(opts, {}, '1.0')
+        os_opts = {"username": "user",
+                   "password": "secret",
+                   "auth_url": "http://example.com:5000/v3"}
+        opts = {"auth_version": "2.0", "prompt": None}
+        do_test(opts, os_opts, '2.0')
+        opts = {"auth_version": "3", "prompt": None}
+        do_test(opts, os_opts, '3')
 
     def test_no_tenant_name_or_id_v2(self):
         os_opts = {"password": "secret",