| # Copyright 2021 The Abseil Authors. |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| """Defines *private* classes used for flag validators. |
| |
| Do NOT import this module. DO NOT use anything from this module. They are |
| private APIs. |
| """ |
| |
| from absl.flags import _exceptions |
| |
| |
| class Validator(object): |
| """Base class for flags validators. |
| |
| Users should NOT overload these classes, and use flags.Register... |
| methods instead. |
| """ |
| |
| # Used to assign each validator an unique insertion_index |
| validators_count = 0 |
| |
| def __init__(self, checker, message): |
| """Constructor to create all validators. |
| |
| Args: |
| checker: function to verify the constraint. |
| Input of this method varies, see SingleFlagValidator and |
| multi_flags_validator for a detailed description. |
| message: str, error message to be shown to the user. |
| """ |
| self.checker = checker |
| self.message = message |
| Validator.validators_count += 1 |
| # Used to assert validators in the order they were registered. |
| self.insertion_index = Validator.validators_count |
| |
| def verify(self, flag_values): |
| """Verifies that constraint is satisfied. |
| |
| flags library calls this method to verify Validator's constraint. |
| |
| Args: |
| flag_values: flags.FlagValues, the FlagValues instance to get flags from. |
| Raises: |
| Error: Raised if constraint is not satisfied. |
| """ |
| param = self._get_input_to_checker_function(flag_values) |
| if not self.checker(param): |
| raise _exceptions.ValidationError(self.message) |
| |
| def get_flags_names(self): |
| """Returns the names of the flags checked by this validator. |
| |
| Returns: |
| [string], names of the flags. |
| """ |
| raise NotImplementedError('This method should be overloaded') |
| |
| def print_flags_with_values(self, flag_values): |
| raise NotImplementedError('This method should be overloaded') |
| |
| def _get_input_to_checker_function(self, flag_values): |
| """Given flag values, returns the input to be given to checker. |
| |
| Args: |
| flag_values: flags.FlagValues, containing all flags. |
| Returns: |
| The input to be given to checker. The return type depends on the specific |
| validator. |
| """ |
| raise NotImplementedError('This method should be overloaded') |
| |
| |
| class SingleFlagValidator(Validator): |
| """Validator behind register_validator() method. |
| |
| Validates that a single flag passes its checker function. The checker function |
| takes the flag value and returns True (if value looks fine) or, if flag value |
| is not valid, either returns False or raises an Exception. |
| """ |
| |
| def __init__(self, flag_name, checker, message): |
| """Constructor. |
| |
| Args: |
| flag_name: string, name of the flag. |
| checker: function to verify the validator. |
| input - value of the corresponding flag (string, boolean, etc). |
| output - bool, True if validator constraint is satisfied. |
| If constraint is not satisfied, it should either return False or |
| raise flags.ValidationError(desired_error_message). |
| message: str, error message to be shown to the user if validator's |
| condition is not satisfied. |
| """ |
| super(SingleFlagValidator, self).__init__(checker, message) |
| self.flag_name = flag_name |
| |
| def get_flags_names(self): |
| return [self.flag_name] |
| |
| def print_flags_with_values(self, flag_values): |
| return 'flag --%s=%s' % (self.flag_name, flag_values[self.flag_name].value) |
| |
| def _get_input_to_checker_function(self, flag_values): |
| """Given flag values, returns the input to be given to checker. |
| |
| Args: |
| flag_values: flags.FlagValues, the FlagValues instance to get flags from. |
| Returns: |
| object, the input to be given to checker. |
| """ |
| return flag_values[self.flag_name].value |
| |
| |
| class MultiFlagsValidator(Validator): |
| """Validator behind register_multi_flags_validator method. |
| |
| Validates that flag values pass their common checker function. The checker |
| function takes flag values and returns True (if values look fine) or, |
| if values are not valid, either returns False or raises an Exception. |
| """ |
| |
| def __init__(self, flag_names, checker, message): |
| """Constructor. |
| |
| Args: |
| flag_names: [str], containing names of the flags used by checker. |
| checker: function to verify the validator. |
| input - dict, with keys() being flag_names, and value for each |
| key being the value of the corresponding flag (string, boolean, |
| etc). |
| output - bool, True if validator constraint is satisfied. |
| If constraint is not satisfied, it should either return False or |
| raise flags.ValidationError(desired_error_message). |
| message: str, error message to be shown to the user if validator's |
| condition is not satisfied |
| """ |
| super(MultiFlagsValidator, self).__init__(checker, message) |
| self.flag_names = flag_names |
| |
| def _get_input_to_checker_function(self, flag_values): |
| """Given flag values, returns the input to be given to checker. |
| |
| Args: |
| flag_values: flags.FlagValues, the FlagValues instance to get flags from. |
| Returns: |
| dict, with keys() being self.flag_names, and value for each key |
| being the value of the corresponding flag (string, boolean, etc). |
| """ |
| return dict([key, flag_values[key].value] for key in self.flag_names) |
| |
| def print_flags_with_values(self, flag_values): |
| prefix = 'flags ' |
| flags_with_values = [] |
| for key in self.flag_names: |
| flags_with_values.append('%s=%s' % (key, flag_values[key].value)) |
| return prefix + ', '.join(flags_with_values) |
| |
| def get_flags_names(self): |
| return self.flag_names |