Add Configuration.from_yaml method

docs/main/changelog.rst

@@ -9,6 +9,7 @@ follows `Semantic versioning`_
 
 Development version
 -------------------
+- Add ``Configuration.from_yaml()`` method to load configuration from yaml file.
 - Add ``Configuration.from_ini()`` method to load configuration from ini file.
 - Add ``Configuration.from_dict()`` method to load configuration from dictionary.
 - Remove undocumented positional parameter of ``DependenciesContainer`` provider.

setup.py

@@ -40,9 +40,11 @@ setup(name='dependency-injector',
       url='https://github.com/ets-labs/python-dependency-injector',
       download_url='https://pypi.python.org/pypi/dependency_injector',
       install_requires=requirements,
-      packages=[
+      extras_require={
-          'dependency_injector',
+          'yaml': [
+              'pyyaml',
           ],
+      },
       package_dir={
           '': 'src',
       },

src/dependency_injector/providers.pyx

@@ -26,6 +26,11 @@ try:
 except ImportError:
     import configparser as iniconfigparser
 
+try:
+    import yaml
+except ImportError:
+    yaml = None
+
 from .errors import (
     Error,
     NoSuchProviderError,
@@ -1192,6 +1197,31 @@ cdef class Configuration(Object):
             current_config = {}
         self.override(merge_dicts(current_config, config))
 
+    def from_yaml(self, filepath):
+        """Load configuration from yaml file.
+
+        Loaded configuration is merged recursively over current configuration.
+
+        :param filepath: Path to the configuration file.
+        :type filepath: str
+
+        :rtype: None
+        """
+        if yaml is None:
+            raise Error(
+                'Unable to load yaml configuration - PyYAML is not installed. '
+                'Install PyYAML or install Dependency Injector with yaml extras: '
+                '"pip install dependency-injector[yaml]"'
+            )
+
+        with open(filepath) as opened_file:
+            config = yaml.load(opened_file, yaml.Loader)
+
+        current_config = self.__call__()
+        if not current_config:
+            current_config = {}
+        self.override(merge_dicts(current_config, config))
+
     def _create_children(self, value):
         children = dict()
 

tests/unit/providers/test_configuration_py2_py3.py

@@ -1,11 +1,12 @@
 """Dependency injector config providers unit tests."""
 
+import contextlib
 import os
 import tempfile
 
 import unittest2 as unittest
 
-from dependency_injector import containers, providers
+from dependency_injector import containers, providers, errors
 
 
 class ConfigTests(unittest.TestCase):
@@ -376,3 +377,91 @@ class ConfigFromIniTests(unittest.TestCase):
         self.assertEqual(self.config.section2.value2(), '2')
         self.assertEqual(self.config.section3(), {'value3': '3'})
         self.assertEqual(self.config.section3.value3(), '3')
+
+
+class ConfigFromYamlTests(unittest.TestCase):
+
+    def setUp(self):
+        self.config = providers.Configuration(name='config')
+
+        _, self.config_file_1 = tempfile.mkstemp()
+        with open(self.config_file_1, 'w') as config_file:
+            config_file.write(
+                'section1:\n'
+                '  value1: 1\n'
+                '\n'
+                'section2:\n'
+                '  value2: 2\n'
+            )
+
+        _, self.config_file_2 = tempfile.mkstemp()
+        with open(self.config_file_2, 'w') as config_file:
+            config_file.write(
+                'section1:\n'
+                '  value1: 11\n'
+                '  value11: 11\n'
+                'section3:\n'
+                '  value3: 3\n'
+            )
+
+    def tearDown(self):
+        del self.config
+        os.unlink(self.config_file_1)
+        os.unlink(self.config_file_2)
+
+    def test(self):
+        self.config.from_yaml(self.config_file_1)
+
+        self.assertEqual(self.config(), {'section1': {'value1': 1}, 'section2': {'value2': 2}})
+        self.assertEqual(self.config.section1(), {'value1': 1})
+        self.assertEqual(self.config.section1.value1(), 1)
+        self.assertEqual(self.config.section2(), {'value2': 2})
+        self.assertEqual(self.config.section2.value2(), 2)
+
+    def test_merge(self):
+        self.config.from_yaml(self.config_file_1)
+        self.config.from_yaml(self.config_file_2)
+
+        self.assertEqual(
+            self.config(),
+            {
+                'section1': {
+                    'value1': 11,
+                    'value11': 11,
+                },
+                'section2': {
+                    'value2': 2,
+                },
+                'section3': {
+                    'value3': 3,
+                },
+            },
+        )
+        self.assertEqual(self.config.section1(), {'value1': 11, 'value11': 11})
+        self.assertEqual(self.config.section1.value1(), 11)
+        self.assertEqual(self.config.section1.value11(), 11)
+        self.assertEqual(self.config.section2(), {'value2': 2})
+        self.assertEqual(self.config.section2.value2(), 2)
+        self.assertEqual(self.config.section3(), {'value3': 3})
+        self.assertEqual(self.config.section3.value3(), 3)
+
+    def test_no_yaml_installed(self):
+        @contextlib.contextmanager
+        def no_yaml_module():
+            yaml = providers.yaml
+            providers.yaml = None
+
+            yield
+
+            providers.yaml = yaml
+
+        with no_yaml_module():
+            with self.assertRaises(errors.Error) as error:
+                self.config.from_yaml(self.config_file_1)
+
+        self.assertEqual(
+            error.exception.args[0],
+            'Unable to load yaml configuration - PyYAML is not installed. '
+            'Install PyYAML or install Dependency Injector with yaml extras: '
+            '"pip install dependency-injector[yaml]"',
+        )

tox.ini

@@ -5,6 +5,7 @@ envlist=
 [testenv]
 deps=
     unittest2
+extras=yaml
 commands=
     unit2 discover -s tests/unit -p test_*_py3.py