improves code 🍰 (#3)

Author: RobertoPrevato

.azuredevops/build.yml

@@ -0,0 +1,44 @@
+trigger:
+  - master
+
+pool:
+  vmImage: 'ubuntu-latest'
+strategy:
+  matrix:
+    Python37:
+      python.version: '3.7'
+    Python38:
+      python.version: '3.8'
+
+steps:
+- task: UsePythonVersion@0
+  inputs:
+    versionSpec: '$(python.version)'
+  displayName: 'Use Python $(python.version)'
+
+- script: |
+    python -m pip install --upgrade pip
+    pip install -r requirements.txt
+  displayName: 'Install dependencies'
+
+- script: flake8
+  displayName: Flake8 test
+
+- script: |
+    pip install pytest pytest-cov
+    pip install https://github.com/RobertoPrevato/pytest-azurepipelines/archive/css_styles.zip
+    python -m pytest tests/ --cov roconfiguration --cov-report html
+  displayName: Run pytest tests
+
+- script: |
+    pip install --upgrade twine setuptools wheel
+    python setup.py sdist bdist_wheel
+  displayName: 'create artifacts'
+  condition: and(succeeded(), eq(variables['python.version'], '3.8'))
+
+- task: PublishBuildArtifacts@1
+  inputs:
+    pathtoPublish: dist
+    artifactName: 'dist_$(python.version)'
+  displayName: 'publish artifacts'
+  condition: and(succeeded(), eq(variables['python.version'], '3.8'))

.flake8

@@ -0,0 +1,6 @@
+[flake8]
+exclude = __pycache__,built,build,venv
+ignore = E203, E266, W503
+max-line-length = 88
+max-complexity = 18
+select = B,C,E,F,W,T4,B9

mypy.ini

@@ -0,0 +1,8 @@
+[mypy]
+python_version = 3.7
+follow_imports = False
+ignore_missing_imports = True
+ignore_errors = False
+warn_redundant_casts = True
+warn_unused_configs = True
+show_column_numbers = True

pytest.ini

@@ -0,0 +1,4 @@
+[pytest]
+markers =
+    cqa: Code Quality Assurance
+junit_family=xunit1

requirements.txt

@@ -1,2 +1,4 @@
 pytest
 PyYAML
+flake8
+mypy

roconfiguration.code-workspace

@@ -0,0 +1,29 @@
+{
+  "folders": [
+    {
+      "path": "."
+    }
+  ],
+  "settings": {
+    "python.testing.pytestArgs": [
+      "."
+    ],
+    "files.trimTrailingWhitespace": true,
+    "files.trimFinalNewlines": true,
+    "python.testing.unittestEnabled": false,
+    "python.testing.nosetestsEnabled": false,
+    "python.testing.pytestEnabled": true,
+    "python.linting.pylintEnabled": false,
+    "python.linting.flake8Enabled": true,
+    "python.linting.mypyEnabled": true,
+    "python.linting.enabled": true,
+    "[python]": {
+        "editor.tabSize": 4,
+        "editor.rulers": [
+            88,
+            100
+        ]
+    },
+    "python.pythonPath": "env/bin/python3.7"
+  }
+}

roconfiguration/__init__.py

@@ -1,12 +1,12 @@
-import os
-import yaml
-import json
 import configparser
-from typing import Union, Dict, Any, Sequence
+import json
+import os
 from collections import abc
+from typing import Any, Dict, Mapping, Optional
 
+import yaml
 
-__all__ = ['Configuration', 'ConfigurationError', 'ConfigurationOverrideError']
+__all__ = ["Configuration", "ConfigurationError", "ConfigurationOverrideError"]
 
 
 class ConfigurationError(Exception):
@@ -18,8 +18,8 @@ class ConfigurationOverrideError(ConfigurationError):
 
 
 def apply_key_value(obj, key, value):
-    key = key.strip('_:')  # remove special characters from both ends
-    for token in (':', '__'):
+    key = key.strip("_:")  # remove special characters from both ends
+    for token in (":", "__"):
         if token in key:
             parts = key.split(token)
 
@@ -31,7 +31,9 @@ def apply_key_value(obj, key, value):
                     try:
                         index = int(part)
                     except ValueError:
-                        raise ConfigurationOverrideError(f'{part} was supposed to be a numeric index in {key}')
+                        raise ConfigurationOverrideError(
+                            f"{part} was supposed to be a numeric index in {key}"
+                        )
 
                     sub_property = sub_property[index]
                     continue
@@ -42,27 +44,38 @@ def apply_key_value(obj, key, value):
                     sub_property[part] = {}
                     sub_property = sub_property[part]
                 else:
-                    if not isinstance(sub_property, abc.Mapping) and not isinstance(sub_property, abc.MutableSequence):
-                        raise ConfigurationOverrideError(f'The key `{key}` cannot be used because it overrides another '
-                                                         f'variable with shorter key! ({part}, {sub_property})')
+                    if not isinstance(sub_property, abc.Mapping) and not isinstance(
+                        sub_property, abc.MutableSequence
+                    ):
+                        raise ConfigurationOverrideError(
+                            f"The key `{key}` cannot be used "
+                            f"because it overrides another "
+                            f"variable with shorter key! ({part}, {sub_property})"
+                        )
 
             if isinstance(sub_property, abc.MutableSequence):
                 try:
                     index = int(last_part)
                 except ValueError:
-                    raise ConfigurationOverrideError(f'{last_part} was supposed to be a numeric index in {key}, '
-                                                     f'because the affected property is a mutable sequence.')
+                    raise ConfigurationOverrideError(
+                        f"{last_part} was supposed to be a numeric index in {key}, "
+                        f"because the affected property is a mutable sequence."
+                    )
 
                 try:
                     sub_property[index] = value
                 except IndexError:
-                    raise ConfigurationOverrideError(f'Invalid override for mutable sequence {key}; '
-                                                     f'assignment index out of range')
+                    raise ConfigurationOverrideError(
+                        f"Invalid override for mutable sequence {key}; "
+                        f"assignment index out of range"
+                    )
             else:
                 try:
                     sub_property[last_part] = value
                 except TypeError as te:
-                    raise ConfigurationOverrideError(f'Invalid assignment {key} -> {value}; {str(te)}')
+                    raise ConfigurationOverrideError(
+                        f"Invalid assignment {key} -> {value}; {str(te)}"
+                    )
 
             return obj
 
@@ -75,7 +88,9 @@ def _develop_configparser_values(parser):
     for section_name in parser.sections():
         section_values = {}
         for k, v in parser[section_name].items():
-            section_values[k] = _develop_configparser_values(v) if isinstance(v, abc.Mapping) else v
+            section_values[k] = (
+                _develop_configparser_values(v) if isinstance(v, abc.Mapping) else v
+            )
         values[section_name] = section_values
     return values
 
@@ -85,10 +100,11 @@ class Configuration:
     Provides methods to handle configuration objects.
     A read-only façade for navigating configuration objects using attribute notation.
 
-    Thanks to Fluent Python, book by Luciano Ramalho; this class is inspired by his example of JSON structure explorer.
+    Thanks to Fluent Python, book by Luciano Ramalho; this class is inspired by his
+    example of JSON structure explorer.
     """
 
-    __slots__ = ('__data',)
+    __slots__ = ("__data",)
 
     def __new__(cls, arg=None):
         if not arg:
@@ -99,12 +115,14 @@ def __new__(cls, arg=None):
             return [cls(item) for item in arg]
         return arg
 
-    def __init__(self, mapping: Union[None, Dict[str, Any], Sequence[Dict[str, Any]]] = None):
-        self.__data = {}
+    def __init__(
+        self, mapping: Optional[Mapping[str, Any]] = None
+    ):
+        self.__data: Dict[str, Any] = {}
         if mapping:
             self.add_map(mapping)
 
-    def __contains__(self, item):
+    def __contains__(self, item: str) -> bool:
         return item in self.__data
 
     def __getitem__(self, name):
@@ -113,19 +131,19 @@ def __getitem__(self, name):
             raise KeyError(name)
         return value
 
-    def __getattr__(self, name, default=None):
+    def __getattr__(self, name, default=None) -> Any:
         if name in self.__data:
             value = self.__data.get(name)
             if isinstance(value, abc.Mapping) or isinstance(value, abc.MutableSequence):
-                return Configuration(value)
+                return Configuration(value)  # type: ignore
             return value
         return default
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return repr(self.values)
 
     @property
-    def values(self):
+    def values(self) -> Dict[str, Any]:
         """
         Returns a copy of the dictionary of current settings.
         """
@@ -134,7 +152,7 @@ def values(self):
     def to_dict(self):
         return self.values
 
-    def add_value(self, name, value):
+    def add_value(self, name: str, value: Any):
         """
         Adds a configuration value by name. The name can contain
         paths to nested objects and list indices.
@@ -144,7 +162,7 @@ def add_value(self, name, value):
         """
         apply_key_value(self.__data, name, value)
 
-    def add_map(self, value):
+    def add_map(self, value: Mapping[str, Any]):
         """
         Merges a mapping object such as a dictionary,
         inside this configuration,
@@ -154,13 +172,18 @@ def add_map(self, value):
         for key, value in value.items():
             self.__data[key] = value
 
-    def add_environmental_variables(self, prefix=None, strip_prefix=False):
+    def add_environmental_variables(
+        self,
+        prefix: Optional[str] = None,
+        strip_prefix: bool = False
+    ):
         """
         Reads environmental variables inside this configuration object,
         optionally filtered by prefix.
 
         :param prefix: optional prefix, to filter read environmental variables.
-        :param strip_prefix: whether to strip the prefix when overriding keys by matched env variables
+        :param strip_prefix: whether to strip the prefix when overriding keys
+        by matched env variables
         """
         if prefix:
             prefix = prefix.lower()
@@ -169,25 +192,30 @@ def add_environmental_variables(self, prefix=None, strip_prefix=False):
             if prefix and not lk.startswith(prefix):
                 continue
             if prefix and strip_prefix:
-                lk = lk[len(prefix):]
+                lk = lk[len(prefix) :]
             apply_key_value(self.__data, lk, v)
 
-    def add_ini(self, ini_settings):
+    def add_ini(self, ini_settings: str) -> None:
         """
         Reads settings from given ini configuration code.
-        
-        :param ini_settings: source ini code 
+
+        :param ini_settings: source ini code
         """
         parser = configparser.ConfigParser()
         parser.read_string(ini_settings)
         self.add_map(_develop_configparser_values(parser))
 
-    def _handle_missing_configuration_file(self, file_path):
-        raise FileNotFoundError(f'missing configuration file: {file_path}')
+    def _handle_missing_configuration_file(self, file_path: str) -> None:
+        raise FileNotFoundError(f"missing configuration file: {file_path}")
 
-    def add_ini_file(self, file_path, optional=False):
+    def add_ini_file(
+        self,
+        file_path: str,
+        optional: bool = False
+    ) -> None:
         """
-        Reads and parse an ini file, merging its values into an instance of Configuration.
+        Reads and parse an ini file, merging its values into an instance of
+        Configuration.
 
         :param file_path: path to an ini file
         :param optional: whether the ini file is optional.
@@ -200,9 +228,14 @@ def add_ini_file(self, file_path, optional=False):
         parser.read(file_path)
         self.add_map(_develop_configparser_values(parser))
 
-    def add_json_file(self, file_path, optional=False):
+    def add_json_file(
+        self,
+        file_path: str,
+        optional: bool = False
+    ) -> None:
         """
-        Reads and parse an json file, merging its values into an instance of Configuration.
+        Reads and parse an json file, merging its values into an instance of
+        Configuration.
 
         :param file_path: path to an json file
         :param optional: whether the json file is optional.
@@ -212,12 +245,18 @@ def add_json_file(self, file_path, optional=False):
                 return
             self._handle_missing_configuration_file(file_path)
 
-        with open(file_path, 'rt', encoding='utf-8') as f:
+        with open(file_path, "rt", encoding="utf-8") as f:
             self.add_map(json.load(f))
 
-    def add_yaml_file(self, file_path, optional=False, safe_load=True):
+    def add_yaml_file(
+        self,
+        file_path: str,
+        optional: bool = False,
+        safe_load: bool = True
+    ) -> None:
         """
-        Reads and parse an yaml file, merging its values into an instance of Configuration.
+        Reads and parse an yaml file, merging its values into an instance of
+        Configuration.
 
         :param file_path: path to an yaml file
         :param optional: whether the yaml file is optional.
@@ -228,7 +267,7 @@ def add_yaml_file(self, file_path, optional=False, safe_load=True):
                 return
             self._handle_missing_configuration_file(file_path)
 
-        with open(file_path, 'rt', encoding='utf-8') as f:
+        with open(file_path, "rt", encoding="utf-8") as f:
 
             if safe_load:
                 data = yaml.safe_load(f)