Add option to disable env var interpolation in configs (#861)

docs/providers/configuration.rst

@@ -366,6 +366,19 @@ See also: :ref:`configuration-strict-mode`.
 
       assert container.config.section.option() is None
 
+If you want to disable environment variables interpolation, pass ``envs_required=None``:
+
+.. code-block:: yaml
+   :caption: templates.yml
+
+   template_string: 'Hello, ${name}!'
+
+.. code-block:: python
+
+   >>> container.config.from_yaml("templates.yml", envs_required=None)
+   >>> container.config.template_string()
+   'Hello, ${name}!'
+
 Mandatory and optional sources
 ------------------------------
 

src/dependency_injector/providers.pyi

@@ -225,20 +225,20 @@ class ConfigurationOption(Provider[Any]):
         self,
         filepath: Union[Path, str],
         required: bool = False,
-        envs_required: bool = False,
+        envs_required: Optional[bool] = False,
     ) -> None: ...
     def from_yaml(
         self,
         filepath: Union[Path, str],
         required: bool = False,
         loader: Optional[Any] = None,
-        envs_required: bool = False,
+        envs_required: Optional[bool] = False,
     ) -> None: ...
     def from_json(
         self,
         filepath: Union[Path, str],
         required: bool = False,
-        envs_required: bool = False,
+        envs_required: Optional[bool] = False,
     ) -> None: ...
     def from_pydantic(
         self, settings: PydanticSettings, required: bool = False, **kwargs: Any

src/dependency_injector/providers.pyx

@@ -15,6 +15,7 @@ import sys
 import threading
 import types
 import warnings
+from configparser import ConfigParser as IniConfigParser
 
 try:
     import contextvars
@@ -41,11 +42,6 @@ try:
 except ImportError:
     _is_coroutine = True
 
-try:
-    import ConfigParser as iniconfigparser
-except ImportError:
-    import configparser as iniconfigparser
-
 try:
     import yaml
 except ImportError:
@@ -102,7 +98,7 @@ config_env_marker_pattern = re.compile(
     r"\${(?P<name>[^}^{:]+)(?P<separator>:?)(?P<default>.*?)}",
 )
 
-def _resolve_config_env_markers(config_content, envs_required=False):
+cdef str _resolve_config_env_markers(config_content: str, envs_required: bool):
     """Replace environment variable markers with their values."""
     findings = list(config_env_marker_pattern.finditer(config_content))
 
@@ -121,28 +117,19 @@ def _resolve_config_env_markers(config_content, envs_required=False):
     return config_content
 
 
-if sys.version_info[0] == 3:
+cdef object _parse_ini_file(filepath, envs_required: bool | None):
-    def _parse_ini_file(filepath, envs_required=False):
+    parser = IniConfigParser()
-        parser = iniconfigparser.ConfigParser()
-        with open(filepath) as config_file:
-            config_string = _resolve_config_env_markers(
-                config_file.read(),
-                envs_required=envs_required,
-            )
-        parser.read_string(config_string)
-        return parser
-else:
-    import StringIO
 
-    def _parse_ini_file(filepath, envs_required=False):
+    with open(filepath) as config_file:
-        parser = iniconfigparser.ConfigParser()
+        config_string = config_file.read()
-        with open(filepath) as config_file:
+
+        if envs_required is not None:
             config_string = _resolve_config_env_markers(
-                config_file.read(),
+                config_string,
                 envs_required=envs_required,
             )
-        parser.readfp(StringIO.StringIO(config_string))
+    parser.read_string(config_string)
-        return parser
+    return parser
 
 
 if yaml:
@@ -1717,7 +1704,7 @@ cdef class ConfigurationOption(Provider):
         try:
             parser = _parse_ini_file(
                 filepath,
-                envs_required=envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+                envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
             )
         except IOError as exception:
             if required is not False \
@@ -1776,10 +1763,11 @@ cdef class ConfigurationOption(Provider):
                 raise
             return
 
-        config_content = _resolve_config_env_markers(
+        if envs_required is not None:
-            config_content,
+            config_content = _resolve_config_env_markers(
-            envs_required=envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+                config_content,
-        )
+                envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+            )
         config = yaml.load(config_content, loader)
 
         current_config = self.__call__()
@@ -1814,10 +1802,11 @@ cdef class ConfigurationOption(Provider):
                 raise
             return
 
-        config_content = _resolve_config_env_markers(
+        if envs_required is not None:
-            config_content,
+            config_content = _resolve_config_env_markers(
-            envs_required=envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+                config_content,
-        )
+                envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+            )
         config = json.loads(config_content)
 
         current_config = self.__call__()
@@ -2270,7 +2259,7 @@ cdef class Configuration(Object):
         try:
             parser = _parse_ini_file(
                 filepath,
-                envs_required=envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+                envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
             )
         except IOError as exception:
             if required is not False \
@@ -2329,10 +2318,11 @@ cdef class Configuration(Object):
                 raise
             return
 
-        config_content = _resolve_config_env_markers(
+        if envs_required is not None:
-            config_content,
+            config_content = _resolve_config_env_markers(
-            envs_required=envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+                config_content,
-        )
+                envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+            )
         config = yaml.load(config_content, loader)
 
         current_config = self.__call__()
@@ -2367,10 +2357,11 @@ cdef class Configuration(Object):
                 raise
             return
 
-        config_content = _resolve_config_env_markers(
+        if envs_required is not None:
-            config_content,
+            config_content = _resolve_config_env_markers(
-            envs_required=envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+                config_content,
-        )
+                envs_required if envs_required is not UNDEFINED else self._is_strict_mode_enabled(),
+            )
         config = json.loads(config_content)
 
         current_config = self.__call__()

tests/unit/providers/configuration/test_from_ini_with_env_py2_py3.py

@@ -5,6 +5,23 @@ import os
 from pytest import mark, raises
 
 
+def test_no_env_variable_interpolation(config, ini_config_file_3):
+    config.from_ini(ini_config_file_3, envs_required=None)
+
+    assert config() == {
+        "section1": {
+            "value1": "${CONFIG_TEST_ENV}",
+            "value2": "${CONFIG_TEST_PATH}/path",
+        },
+    }
+    assert config.section1() == {
+        "value1": "${CONFIG_TEST_ENV}",
+        "value2": "${CONFIG_TEST_PATH}/path",
+    }
+    assert config.section1.value1() == "${CONFIG_TEST_ENV}"
+    assert config.section1.value2() == "${CONFIG_TEST_PATH}/path"
+
+
 def test_env_variable_interpolation(config, ini_config_file_3):
     config.from_ini(ini_config_file_3)
 

tests/unit/providers/configuration/test_from_json_with_env_py2_py3.py

@@ -6,6 +6,23 @@ import os
 from pytest import mark, raises
 
 
+def test_no_env_variable_interpolation(config, json_config_file_3):
+    config.from_json(json_config_file_3, envs_required=None)
+
+    assert config() == {
+        "section1": {
+            "value1": "${CONFIG_TEST_ENV}",
+            "value2": "${CONFIG_TEST_PATH}/path",
+        },
+    }
+    assert config.section1() == {
+        "value1": "${CONFIG_TEST_ENV}",
+        "value2": "${CONFIG_TEST_PATH}/path",
+    }
+    assert config.section1.value1() == "${CONFIG_TEST_ENV}"
+    assert config.section1.value2() == "${CONFIG_TEST_PATH}/path"
+
+
 def test_env_variable_interpolation(config, json_config_file_3):
     config.from_json(json_config_file_3)
 

tests/unit/providers/configuration/test_from_yaml_with_env_py2_py3.py

@@ -6,6 +6,23 @@ import yaml
 from pytest import mark, raises
 
 
+def test_no_env_variable_interpolation(config, yaml_config_file_3):
+    config.from_yaml(yaml_config_file_3, envs_required=None)
+
+    assert config() == {
+        "section1": {
+            "value1": "${CONFIG_TEST_ENV}",
+            "value2": "${CONFIG_TEST_PATH}/path",
+        },
+    }
+    assert config.section1() == {
+        "value1": "${CONFIG_TEST_ENV}",
+        "value2": "${CONFIG_TEST_PATH}/path",
+    }
+    assert config.section1.value1() == "${CONFIG_TEST_ENV}"
+    assert config.section1.value2() == "${CONFIG_TEST_PATH}/path"
+
+
 def test_env_variable_interpolation(config, yaml_config_file_3):
     config.from_yaml(yaml_config_file_3)