Support suppress meta option on Prompt to suppress user input.

- Resolves Issue #621

CHANGELOG.md

@@ -18,7 +18,8 @@ Bugs:
 
 Features:
 
-- None
+- `[utils.shell]` Support `suppress` meta option on `Prompt` to suppress user input.
+    - [Issue #621](https://github.com/datafolklabs/cement/issues/621)
 
 
 Refactoring:

cement/utils/shell.py

@@ -1,6 +1,8 @@
 """Common Shell Utilities."""
 
 import os
+import builtins
+from getpass import getpass
 from subprocess import Popen, PIPE
 from multiprocessing import Process
 from threading import Thread
@@ -388,9 +390,13 @@ class Prompt(MetaMixin):
         max_attempts = 10
 
         #: Raise an exception when max_attempts is hit?  If not, Prompt
-        #: passes the input through as `None`.
+        #: passes the input through as ``None``.
         max_attempts_exception = True
 
+        #: Suppress user input (use ``getpass.getpass`` instead of
+        #: ``builtins.input``. Default: ``False``.
+        suppress = False
+
     def __init__(self, text=None, *args, **kw):
         if text is not None:
             kw['text'] = text
@@ -400,6 +406,18 @@ class Prompt(MetaMixin):
         if self._meta.auto:
             self.prompt()
 
+    def _get_suppressed_input(self, text):
+        return getpass(text)  # pragma: nocover
+
+    def _get_unsuppressed_input(self, text):
+        return builtins.input(text)  # pragma: nocover
+
+    def _get_input(self, text):
+        if self._meta.suppress is True:
+            return self._get_suppressed_input(text)  # pragma: nocover
+        else:
+            return self._get_unsuppressed_input(text)  # pragma: nocover
+
     def _prompt(self):
         if self._meta.clear:
             os.system(self._meta.clear_command)
@@ -421,7 +439,8 @@ class Prompt(MetaMixin):
         else:
             text = self._meta.text
 
-        self.input = input("%s " % text)
+        self.input = self._get_input("%s " % text)
+        # self.input = input("%s " % text)
         if self.input == '' and self._meta.default is not None:
             self.input = self._meta.default
         elif self.input == '':

tests/utils/test_shell.py

@@ -6,7 +6,8 @@ from pytest import raises
 from cement.utils import shell
 from cement.core.exc import FrameworkError
 
-INPUT = 'builtins.input'
+# INPUT = 'builtins.input'
+INPUT = 'cement.utils.shell.Prompt._get_input'
 
 
 def add(a, b):
@@ -209,3 +210,9 @@ def test_prompt_case_sensitive():
             max_attempts_exception=False,
         )
         assert p.input is None
+
+
+def test_prompt_suppress_user_input():
+    with mock.patch(INPUT, return_value='UBER_SECURE_PASSWORD'):
+        p = shell.Prompt("Input password", suppress=True)
+        assert p.input == 'UBER_SECURE_PASSWORD'