Introduced import_by_environment() function.

CHANGELOG

@@ -2,6 +2,11 @@ envbox changelog
 ================
 
 
+Unreleased
+----------
++ Introduced 'import_by_environment()' function.
+
+
 v0.1.0
 ------
-+ Basic functionality.
++ Basic functionality.

README.rst

@@ -28,6 +28,7 @@ Features
 
 * Environment type detection (extendable system);
 * Convenient ``os.environ`` proxying (with optional values casting into Python natives);
+* Automatic submodule-for-environment import tool;
 * CLI for environment type probing.
 
 

docs/source/quickstart.rst

@@ -3,7 +3,7 @@ Quickstart
 
 
 Basic usage
-~~~~~~~~~~~
+-----------
 
 .. code-block:: python
 
@@ -37,7 +37,7 @@ Basic usage
 
 
 Environment type aliases
-~~~~~~~~~~~~~~~~~~~~~~~~
+------------------------
 
 .. code-block:: python
 
@@ -50,3 +50,41 @@ Environment type aliases
     # we correctly identify it as production environment.
     get_environment().is_production  # True
 
+
+
+Automatic submodule import
+--------------------------
+
+**envbox** features ``import_by_environment()`` function which automatically imports symbols of a submodule
+of a package for given (or detected) environment into globals of an entry-point submodule.
+
+.. note:: This could be useful not only for Django-projects where submodule-based settings definition is rather usual
+  but also for varius other cases.
+
+
+Example::
+
+    - project
+    --- __init__.py
+    --- settings.py
+    --- settings_development.py
+
+1. Here ``project`` is a package available for import (note ``__init__.py``).
+
+2. ``settings.py`` is an entry point module for settings using ``import_by_environment()``.
+
+    .. code-block:: python
+
+        from envbox import import_by_environment
+
+
+        current_env = import_by_environment()
+
+        print('Environment type: %s' % current_env)
+
+
+3. ``settings_development.py`` is one of module files for certain environment (development).
+
+4. ``import_by_environment()`` call in ``settings.py`` makes symbols from ``settings_development.py``
+   available from ``settings.py``.
+

envbox/__init__.py

@@ -1,4 +1,4 @@
-from .base import get_environment
+from .base import get_environment, import_by_environment
 from .envs import DEVELOPMENT, TESTING, STAGING, PRODUCTION, Environment
 
 

envbox/base.py

@@ -1,3 +1,7 @@
+from os.path import dirname, basename
+from inspect import currentframe
+from importlib import import_module
+
 from .detectors import DETECTORS, get_detector
 from .envs import Environment, DEVELOPMENT, get_type
 
@@ -40,3 +44,57 @@ def get_environment(default=DEVELOPMENT, detectors=None, detectors_opts=None):
         env = env()
 
     return env
+
+
+def import_by_environment(environment=None, module_name_pattern='settings_%s', silent=False):
+    """Automatically imports symbols of a submodule of a package for given
+    (or detected) environment into globals of an entry-point submodule.
+
+    Example::
+
+        - project
+        --- __init__.py
+        --- settings.py
+        --- settings_development.py
+
+    * Here ``project`` is a package available for import (note ``__init__.py``).
+
+    * ``settings.py`` is an entry point module for settings using ``import_by_environment()``.
+
+    * ``settings_development.py`` is one of module files for certain environment (development).
+
+    * ``import_by_environment()`` call in ``settings.py`` makes symbols from ``settings_development.py``
+      available from ``settings.py``.
+
+    :param Environment environment:
+
+    :param str|unicode module_name_pattern: Environment submodule name pattern.
+        ``%s`` will be replaced with environment name.
+
+    :param bool silent: If ``True`` no import error (if any) will be raised.
+
+    :rtype: Environment|None
+
+    :returns: ``Environment`` object if module is imported or ``None``.
+
+    """
+    environment = environment or get_environment()
+
+    module_name_pattern = '.' + module_name_pattern
+
+    settings_module = currentframe().f_back
+    package_name = basename(dirname(settings_module.f_code.co_filename))
+
+    result = None
+
+    try:
+        env_module = import_module(module_name_pattern % environment, package_name)
+        settings_module.f_globals.update(env_module.__dict__)
+
+        result = environment
+
+    except (ImportError, SystemError):
+        if not silent:
+            raise
+
+    return result

tests/test_envs.py

@@ -47,8 +47,6 @@ def test_set_get():
     env.one = 3
     assert env.one == '3'
 
-    print(dict(env.getmany_casted('PYTHON')))
-
 
 def test_set_get_many():
 

tests/test_module.py

@@ -2,7 +2,7 @@
 
 import pytest
 
-from envbox import get_environment, PRODUCTION
+from envbox import get_environment, PRODUCTION, import_by_environment
 
 
 def test_get_environment():
@@ -22,3 +22,17 @@ def test_get_environment():
 
     assert env.is_production
     assert env == PRODUCTION
+
+
+def test_autoimport(monkeypatch):
+
+    with pytest.raises(SystemError):
+        import_by_environment()
+
+    def import_it(*args):
+        return type('DummyModule', (object,), {})
+
+    monkeypatch.setattr('envbox.base.import_module', import_it)
+    env = import_by_environment()
+
+    assert env.is_development