Work in progress: Replicate Django-environ FileAwareEnv

environs/__init__.py

@@ -495,7 +495,7 @@ def _get_from_environ(
         proxy env key.
         """
         env_key = self._get_key(key, omit_prefix=proxied)
-        value = os.environ.get(env_key, default)
+        value = self._get_value(env_key, default)
         if hasattr(value, "strip"):
             expand_match = self.expand_vars and _EXPANDED_VAR_PATTERN.match(value)
             if expand_match:  # Full match expand_vars - special case keep default
@@ -535,3 +535,20 @@ def _expand_vars(self, parsed_key, value):
 
     def _get_key(self, key: _StrType, *, omit_prefix: _BoolType = False) -> _StrType:
         return self._prefix + key if self._prefix and not omit_prefix else key
+
+    @staticmethod
+    def _get_value(env_key, default):
+        return os.environ.get(env_key, default)
+
+
+class FileAwareEnv(Env):
+    """An environment variable reader that supports reading values from files."""
+
+    @staticmethod
+    def _get_value(env_key, default):
+        file_key = env_key + "_FILE"
+        if file_location := os.environ.get(file_key, None):
+            return Path(file_location).read_text()
+        else:
+            return os.environ.get(env_key, default)
+

tests/test_environs.py

@@ -837,3 +837,18 @@ def test_composite_types(self, env, set_env):
             "foo": "bar",
             "wget_params": '--header="Referer: https://radiocut.fm/"',
         }
+
+
+class TestFileAwareEnv:
+    @pytest.fixture
+    def env(self):
+        return environs.FileAwareEnv(expand_vars=True)
+
+    def test_full_expand_vars(self, env, set_env):
+        set_env(
+            {
+                "MAIN": "legacy_value",
+                "MAIN_FILE": HERE / "subfolder/.another.env",
+            }
+        )
+        assert env.str("MAIN") == "CUSTOM_STRING=bar\n"