Rework Config-File Handling (getnikola#3244)

Author: neurolag

AUTHORS.txt

@@ -64,6 +64,7 @@
 * `Leandro Poblet <https://github.com/DoctorMalboro>`_
 * `Luis Miguel Morillas <https://github.com/lmorillas>`_
 * `Manuel Kaufmann <https://github.com/humitos>`_
+* `Manuel Thalmann <https://github.com/manuth>`_
 * `Marcelo MD <https://github.com/marcelomd>`_
 * `Marcos Dione <https://github.com/StyXman>`_
 * `Mariano Guerra <https://github.com/marianoguerra>`_

CHANGES.txt

@@ -13,6 +13,7 @@ Features
 * Add Interlingua translation by Alberto Mardegan
 * Add Afrikaans translation by Friedel Wolff
 * Support for docutils.conf (Issue #3188)
+* Add support for inherited config-files
 
 Bugfixes
 --------

docs/manual.rst

@@ -1487,7 +1487,10 @@ you can't, this will work.
 Configuration
 -------------
 
-The configuration file is called ``conf.py`` and can be used to customize a lot of
+You can pass a configuration file to ``nikola`` by using the ``--conf`` command line switch.
+Otherwise the ``conf.py`` file in the root of the Nikola website will be used.
+
+The configuration file can be used to customize a lot of
 what Nikola does. Its syntax is python, but if you don't know the language, it
 still should not be terribly hard to grasp.
 
@@ -1511,10 +1514,33 @@ them.  For those options, two types of values can be provided:
 * a string, which will be used for all languages
 * a dict of language-value pairs, to have different values in each language
 
-.. note:: It is possible to load the configuration from another file by specifying
-          ``--conf=path/to/other.file`` on Nikola's command line. For example, to
-          build your blog using the configuration file ``configurations/test.conf.py``,
-          you have to execute ``nikola build --conf=configurations/test.conf.py``.
+.. note::
+    As of version 8.0.3 it is possible to create configuration files which inherit values from other Python files.
+    This might be useful if you're working with similar environments.
+
+    Example:
+        conf.py:
+            .. code:: python
+            
+                BLOG_AUTHOR = "Your Name"
+                BLOG_TITLE = "Demo Site"
+                SITE_URL = "https://yourname.github.io/demo-site
+                BLOG_EMAIL = "[email protected]"
+                BLOG_DESCRIPTION = "This is a demo site for Nikola."
+
+        debug.conf.py:
+            .. code:: python
+
+                import conf
+                globals().update(vars(conf))
+                SITE_URL = "http://localhost:8000/"
+
+            or
+
+            .. code:: python
+
+                from conf import *
+                SITE_URL = "http://localhost:8000/"
 
 Customizing Your Site
 ---------------------

dodo.py

@@ -1,7 +1,6 @@
 
 import os
 import fnmatch
-import subprocess
 
 DOIT_CONFIG = {
     'default_tasks': ['flake8', 'test'],

nikola/__main__.py

@@ -26,6 +26,7 @@
 
 """The main function of Nikola."""
 
+import imp
 import os
 import shutil
 import sys
@@ -56,9 +57,6 @@
 except ImportError:
     pass  # This is only so raw_input/input does nicer things if it's available
 
-
-import importlib.machinery
-
 config = {}
 
 # DO NOT USE unless you know what you are doing!
@@ -117,23 +115,36 @@ def main(args=None):
             os.chdir(root)
         # Help and imports don't require config, but can use one if it exists
         needs_config_file = (argname != 'help') and not argname.startswith('import_')
+        if needs_config_file:
+            if root is None:
+                LOGGER.error("The command could not be executed: You're not in a nikola website.")
+                return 1
+            else:
+                LOGGER.info("Website root: '{0}'".format(root))
     else:
         needs_config_file = False
 
-    sys.path.append('')
+    old_path = sys.path
+    old_modules = sys.modules
+
     try:
-        loader = importlib.machinery.SourceFileLoader("conf", conf_filename)
-        conf = loader.load_module()
-        config = conf.__dict__
+        sys.path = sys.path[:]
+        sys.modules = sys.modules.copy()
+        sys.path.insert(0, os.path.dirname(conf_filename))
+        with open(conf_filename, "rb") as file:
+            config = imp.load_module(conf_filename, file, conf_filename, (None, "rb", imp.PY_SOURCE)).__dict__
     except Exception:
+        config = {}
         if os.path.exists(conf_filename):
             msg = traceback.format_exc(0)
             LOGGER.error('"{0}" cannot be parsed.\n{1}'.format(conf_filename, msg))
             return 1
         elif needs_config_file and conf_filename_changed:
             LOGGER.error('Cannot find configuration file "{0}".'.format(conf_filename))
             return 1
-        config = {}
+    finally:
+        sys.path = old_path
+        sys.modules = old_modules
 
     if conf_filename_changed:
         LOGGER.info("Using config file '{0}'".format(conf_filename))

tests/data/test_config/conf.py

@@ -0,0 +1,30 @@
+# -*- coding: utf-8 -*-
+import time
+
+BLOG_AUTHOR = "Your Name"
+BLOG_TITLE = "Demo Site"
+SITE_URL = "https://example.com/"
+BLOG_EMAIL = "[email protected]"
+BLOG_DESCRIPTION = "This is a demo site for Nikola."
+DEFAULT_LANG = "en"
+CATEGORY_ALLOW_HIERARCHIES = False
+CATEGORY_OUTPUT_FLAT_HIERARCHY = False
+HIDDEN_CATEGORIES = []
+HIDDEN_AUTHORS = ['Guest']
+LICENSE = ""
+
+CONTENT_FOOTER_FORMATS = {
+    DEFAULT_LANG: (
+        (),
+        {
+            "email": BLOG_EMAIL,
+            "author": BLOG_AUTHOR,
+            "date": time.gmtime().tm_year,
+            "license": LICENSE
+        }
+    )
+}
+
+ADDITIONAL_METADATA = {
+    "ID": "conf"
+}

tests/data/test_config/config.with+illegal(module)name.characters.py

@@ -0,0 +1,6 @@
+import conf
+
+globals().update(vars(conf))
+ADDITIONAL_METADATA = {
+    "ID": "illegal"
+}

tests/data/test_config/prod.py

@@ -0,0 +1,6 @@
+import conf
+
+globals().update(vars(conf))
+ADDITIONAL_METADATA = {
+    "ID": "prod"
+}

tests/test_config.py

@@ -0,0 +1,44 @@
+# -*- coding: utf-8 -*-
+import os
+import re
+
+from nikola import __main__ as nikola
+
+from .base import BaseTestCase
+
+
+class ConfigTest(BaseTestCase):
+    """Provides tests for the configuration-file handling."""
+    @classmethod
+    def setUpClass(self):
+        self.metadata_option = "ADDITIONAL_METADATA"
+        script_root = os.path.dirname(__file__)
+        test_dir = os.path.join(script_root, "data", "test_config")
+        nikola.main(["--conf=" + os.path.join(test_dir, "conf.py")])
+        self.simple_config = nikola.config
+        nikola.main(["--conf=" + os.path.join(test_dir, "prod.py")])
+        self.complex_config = nikola.config
+        nikola.main(["--conf=" + os.path.join(test_dir, "config.with+illegal(module)name.characters.py")])
+        self.complex_filename_config = nikola.config
+        self.check_base_equality(self.complex_filename_config)
+
+    @classmethod
+    def check_base_equality(self, config):
+        """Check whether the specified `config` equals the base config."""
+        for option in self.simple_config.keys():
+            if re.match("^[A-Z]+(_[A-Z]+)*$", option) and option != self.metadata_option:
+                assert self.simple_config[option] == self.complex_config[option]
+
+    def test_simple_config(self):
+        """Check whether configuration-files without ineritance are interpreted correctly."""
+        assert self.simple_config[self.metadata_option]["ID"] == "conf"
+
+    def test_inherited_config(self):
+        """Check whether configuration-files with ineritance are interpreted correctly."""
+        self.check_base_equality(config=self.complex_config)
+        assert self.complex_config[self.metadata_option]["ID"] == "prod"
+
+    def test_config_with_illegal_filename(self):
+        """Check whether files with illegal module-name characters can be set as config-files, too."""
+        self.check_base_equality(config=self.complex_filename_config)
+        assert self.complex_filename_config[self.metadata_option]["ID"] == "illegal"