Add configured defaults (#145)

* Initial work.

* Finish configured defaults.

* Fix mock imports for Python 2.7

* Code review feedback.

Author: tjprescott

knack/commands.py

@@ -17,6 +17,7 @@
 from .events import (EVENT_CMDLOADER_LOAD_COMMAND_TABLE, EVENT_CMDLOADER_LOAD_ARGUMENTS,
                      EVENT_COMMAND_CANCELLED)
 from .log import get_logger
+from .validators import DefaultInt, DefaultStr
 
 logger = get_logger(__name__)
 
@@ -71,6 +72,18 @@ def __init__(self, cli_ctx, name, handler, description=None, table_transformer=N
     def should_load_description(self):
         return not self.cli_ctx.data['completer_active']
 
+    def _resolve_default_value_from_config_file(self, arg, overrides):
+        default_key = overrides.settings.get('configured_default', None)
+        if not default_key:
+            return
+
+        defaults_section = self.cli_ctx.config.defaults_section_name
+        config_value = self.cli_ctx.config.get(defaults_section, default_key, None)
+        if config_value:
+            logger.info("Configured default '%s' for arg %s", config_value, arg.name)
+            overrides.settings['default'] = DefaultStr(config_value)
+            overrides.settings['required'] = False
+
     def load_arguments(self):
         if self.arguments_loader:
             cmd_args = self.arguments_loader()
@@ -87,7 +100,20 @@ def add_argument(self, param_name, *option_strings, **kwargs):
 
     def update_argument(self, param_name, argtype):
         arg = self.arguments[param_name]
+        # resolve defaults from either environment variable or config file
+        self._resolve_default_value_from_config_file(arg, argtype)
         arg.type.update(other=argtype)
+        arg_default = arg.type.settings.get('default', None)
+        # apply DefaultStr and DefaultInt to allow distinguishing between
+        # when a default was applied or when the user specified a value
+        # that coincides with the default
+        if isinstance(arg_default, str):
+            arg_default = DefaultStr(arg_default)
+        elif isinstance(arg_default, int):
+            arg_default = DefaultInt(arg_default)
+        # update the default
+        if arg_default:
+            arg.type.settings['default'] = arg_default
 
     def execute(self, **kwargs):
         return self(**kwargs)

knack/config.py

@@ -23,6 +23,7 @@ class CLIConfig(object):
     _DEFAULT_CONFIG_ENV_VAR_PREFIX = 'CLI'
     _DEFAULT_CONFIG_DIR = os.path.join('~', '.{}'.format('cli'))
     _DEFAULT_CONFIG_FILE_NAME = 'config'
+    _CONFIG_DEFAULTS_SECTION = 'defaults'
 
     def __init__(self, config_dir=None, config_env_var_prefix=None, config_file_name=None):
         """ Manages configuration options available in the CLI
@@ -44,6 +45,7 @@ def __init__(self, config_dir=None, config_env_var_prefix=None, config_file_name
         configuration_file_name = config_file_name or CLIConfig._DEFAULT_CONFIG_FILE_NAME
         self.config_path = os.path.join(self.config_dir, configuration_file_name)
         self._env_var_format = '{}{}'.format(env_var_prefix, '{section}_{option}')
+        self.defaults_section_name = CLIConfig._CONFIG_DEFAULTS_SECTION
         self.config_parser.read(self.config_path)
 
     def env_var_name(self, section, option):

knack/testsdk/patches.py

@@ -4,7 +4,10 @@
 # --------------------------------------------------------------------------------------------
 
 import unittest
-import mock
+try:
+    import mock
+except ImportError:
+    from unittest import mock
 from .exceptions import CliTestError
 
 

knack/validators.py

@@ -0,0 +1,20 @@
+# --------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for license information.
+# --------------------------------------------------------------------------------------------
+
+
+class DefaultStr(str):
+
+    def __new__(cls, *args, **kwargs):
+        instance = str.__new__(cls, *args, **kwargs)
+        instance.is_default = True
+        return instance
+
+
+class DefaultInt(int):
+
+    def __new__(cls, *args, **kwargs):
+        instance = int.__new__(cls, *args, **kwargs)
+        instance.is_default = True
+        return instance

tests/test_cli_scenarios.py

@@ -5,6 +5,10 @@
 
 import os
 import unittest
+try:
+    import mock
+except ImportError:
+    from unittest import mock
 import mock
 
 from collections import OrderedDict

tests/test_command_with_configured_defaults.py

@@ -0,0 +1,90 @@
+# --------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for license information.
+# --------------------------------------------------------------------------------------------
+from __future__ import print_function
+import os
+import logging
+import unittest
+try:
+    import mock
+except ImportError:
+    from unittest import mock
+from six import StringIO
+import sys
+
+from knack.arguments import ArgumentsContext
+from knack.commands import CLICommandsLoader, CLICommand, CommandGroup
+from knack.config import CLIConfig
+from tests.util import DummyCLI, redirect_io
+
+
+# a dummy callback for arg-parse
+def load_params(_):
+    pass
+
+
+def list_foo(my_param):
+    print(str(my_param), end='')
+
+
+class TestCommandWithConfiguredDefaults(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        # Ensure initialization has occurred correctly
+        logging.basicConfig(level=logging.DEBUG)
+
+    @classmethod
+    def tearDownClass(cls):
+        logging.shutdown()
+
+    def _set_up_command_table(self, required):
+
+        class TestCommandsLoader(CLICommandsLoader):
+
+            def load_command_table(self, args):
+                super(TestCommandsLoader, self).load_command_table(args)
+                with CommandGroup(self, 'foo', '{}#{{}}'.format(__name__)) as g:
+                    g.command('list', 'list_foo')
+                return self.command_table
+
+            def load_arguments(self, command):
+                with ArgumentsContext(self, 'foo') as c:
+                    c.argument('my_param', options_list='--my-param',
+                               configured_default='param', required=required)
+                super(TestCommandsLoader, self).load_arguments(command)
+        self.cli_ctx = DummyCLI(commands_loader_cls=TestCommandsLoader)
+
+    @mock.patch.dict(os.environ, {'CLI_DEFAULTS_PARAM': 'myVal'})
+    @redirect_io
+    def test_apply_configured_defaults_on_required_arg(self):
+        self._set_up_command_table(required=True)
+        self.cli_ctx.invoke('foo list'.split())
+        actual = self.io.getvalue()
+        expected = 'myVal'
+        self.assertEqual(expected, actual)
+
+    @redirect_io
+    def test_no_configured_default_on_required_arg(self):
+        self._set_up_command_table(required=True)
+        with self.assertRaises(SystemExit):
+            self.cli_ctx.invoke('foo list'.split())
+        actual = self.io.getvalue()
+        expected = 'required: --my-param'
+        if sys.version_info[0] == 2:
+            expected = 'argument --my-param is required'
+        self.assertEqual(expected in actual, True)
+
+    @mock.patch.dict(os.environ, {'CLI_DEFAULTS_PARAM': 'myVal'})
+    @redirect_io
+    def test_apply_configured_defaults_on_optional_arg(self):
+        self._set_up_command_table(required=False)
+        self.cli_ctx.invoke('foo list'.split())
+        actual = self.io.getvalue()
+        expected = 'myVal'
+        self.assertEqual(expected, actual)
+
+
+if __name__ == '__main__':
+    unittest.main()

tests/test_completion.py

@@ -5,7 +5,10 @@
 
 import os
 import unittest
-import mock
+try:
+    import mock
+except ImportError:
+    from unittest import mock
 
 from knack.completion import CLICompletion, CaseInsensitiveChoicesCompleter, ARGCOMPLETE_ENV_NAME
 from tests.util import MockContext

tests/test_config.py

@@ -7,7 +7,10 @@
 import stat
 import unittest
 import tempfile
-import mock
+try:
+    import mock
+except ImportError:
+    from unittest import mock
 from six.moves import configparser
 
 from knack.config import CLIConfig, get_config_parser

tests/test_deprecation.py

@@ -5,16 +5,17 @@
 
 from __future__ import unicode_literals
 
-import sys
 import unittest
-import mock
+try:
+    import mock
+except ImportError:
+    from unittest import mock
 from threading import Lock
-from six import StringIO
 
 from knack.arguments import ArgumentsContext
 from knack.commands import CLICommand, CLICommandsLoader, CommandGroup
 
-from tests.util import DummyCLI
+from tests.util import DummyCLI, redirect_io
 
 
 def example_handler(arg1, arg2=None, arg3=None):
@@ -27,20 +28,6 @@ def example_arg_handler(arg1, opt1, arg2=None, opt2=None, arg3=None,
     pass
 
 
-original_stdout = sys.stdout
-original_stderr = sys.stderr
-
-
-def redirect_io(func):
-    def wrapper(self):
-        sys.stdout = sys.stderr = self.io = StringIO()
-        func(self)
-        self.io.close()
-        sys.stdout = original_stderr
-        sys.stderr = original_stderr
-    return wrapper
-
-
 class TestCommandDeprecation(unittest.TestCase):
 
     def setUp(self):

tests/test_log.py

@@ -4,7 +4,10 @@
 # --------------------------------------------------------------------------------------------
 
 import unittest
-import mock
+try:
+    import mock
+except ImportError:
+    from unittest import mock
 import logging
 import colorama
 

tests/test_prompting.py

@@ -5,7 +5,10 @@
 
 import sys
 import unittest
-import mock
+try:
+    import mock
+except ImportError:
+    from unittest import mock
 from six import StringIO
 
 from knack.prompting import (verify_is_a_tty, NoTTYException, _INVALID_PASSWORD_MSG, prompt,

tests/util.py

@@ -3,11 +3,29 @@
 # Licensed under the MIT License. See License.txt in the project root for license information.
 # --------------------------------------------------------------------------------------------
 
-import mock
+try:
+    import mock
+except ImportError:
+    from unittest import mock
+import sys
 import tempfile
+from six import StringIO
 
 from knack.cli import CLI, CLICommandsLoader, CommandInvoker
 
+def redirect_io(func):
+
+    original_stderr = sys.stderr
+    original_stdout = sys.stdout
+
+    def wrapper(self):
+        sys.stdout = sys.stderr = self.io = StringIO()
+        func(self)
+        self.io.close()
+        sys.stdout = original_stderr
+        sys.stderr = original_stderr
+    return wrapper
+
 
 class MockContext(CLI):