Added support for multiple config files

doc

@@ -1 +1 @@
-Subproject commit 4599a339dbd4a2299a8eca575a7b801686d9fc5a
+Subproject commit d5dc5f794ad1b959b9d4dce47eeb6068e5a75115

matemat/__main__.py

@@ -1,5 +1,5 @@
 
-from typing import Any, Dict
+from typing import Any, Dict, Iterable, Union
 
 import sys
 
@@ -12,9 +12,9 @@ if __name__ == '__main__':
     from matemat.webserver import MatematWebserver
 
     # Use config file name from command line, if present
-    configfile: str = '/etc/matemat.conf'
+    configfile: Union[str, Iterable[str]] = '/etc/matemat.conf'
     if len(sys.argv) > 1:
-        configfile = sys.argv[1]
+        configfile = sys.argv[1:]
 
     # Parse the config file
     config: Dict[str, Any] = parse_config_file(configfile)

matemat/webserver/config.py

@@ -1,15 +1,15 @@
 
-from typing import Any, Dict
+from typing import Any, Dict, Iterable, List, Union
 
 import os
 from configparser import ConfigParser
 
 
-def parse_config_file(path: str) -> Dict[str, Any]:
+def parse_config_file(paths: Union[str, Iterable[str]]) -> Dict[str, Any]:
     """
     Parse the configuration file at the given path.
 
-    :param path: The config file to parse.
+    :param paths: The config file(s) to parse.
     :return: A dictionary containing the parsed configuration.
     """
     # Set up default values
@@ -30,8 +30,17 @@ def parse_config_file(path: str) -> Dict[str, Any]:
     parser: ConfigParser = ConfigParser()
     # Replace the original option transformation by a string constructor to preserve the case of config keys
     parser.optionxform = str
-    # Read the configuration file
+    # Normalize the input argument (turn a scalar into a list and expand ~ in paths)
-    parser.read(os.path.expanduser(path), 'utf-8')
+    files: List[str] = list()
+    if isinstance(paths, str):
+        files.append(os.path.expanduser(paths))
+    else:
+        for path in paths:
+            if not isinstance(path, str):
+                raise TypeError(f'Not a string: {path}')
+            files.append(os.path.expanduser(path))
+    # Read the configuration files
+    parser.read(files, 'utf-8')
 
     # Read values from the [Matemat] section, if present, falling back to default values
     if 'Matemat' in parser.sections():

matemat/webserver/test/test_config.py

@@ -1,4 +1,6 @@
 
+from typing import List
+
 from unittest import TestCase
 from unittest.mock import patch
 
@@ -24,17 +26,54 @@ UploadDir= /var/test/static/upload
 DatabaseFile=/var/test/db/test.db
 '''
 
+_PARTIAL_CONFIG = '''
+[Matemat]
+Port=443
+
+[Pagelets]
+Name=Matemat (Unit Test 2)
+'''
+
+
+class IterOpenMock:
+    """
+    Enable mocking of subsequent open() class for different files.  Usage:
+
+    with mock.patch('builtins.open', IterOpenMock(['content 1', 'content 2'])):
+        ...
+            with open('foo') as f:
+                # Reading from f will yield 'content 1'
+            with open('foo') as f:
+                # Reading from f will yield 'content 2'
+    """
+
+    def __init__(self, files: List[str]):
+        self.files = files
+
+    def __enter__(self):
+        return StringIO(self.files[0])
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.files = self.files[1:]
+
 
 class TestConfig(TestCase):
 
     def test_parse_config_empty_defualt_values(self):
+        """
+        Test that default values are set when reading an empty config file.
+        """
+        # Mock the open() function to return an empty config file example
         with patch('builtins.open', return_value=StringIO(_EMPTY_CONFIG)):
+            # The filename is only a placeholder, file content is determined by mocking open
             config = parse_config_file('test')
+        # Make sure all mandatory values are present
         self.assertIn('listen', config)
         self.assertIn('port', config)
         self.assertIn('staticroot', config)
         self.assertIn('templateroot', config)
         self.assertIn('pagelet_variables', config)
+        # Make sure all mandatory values are set to their default
         self.assertEqual('::', config['listen'])
         self.assertEqual(80, config['port'])
         self.assertEqual('/var/matemat/static', config['staticroot'])
@@ -43,8 +82,14 @@ class TestConfig(TestCase):
         self.assertEqual(0, len(config['pagelet_variables']))
 
     def test_parse_config_full(self):
+        """
+        Test that all default values are overridden by the values provided in the config file.
+        """
+        # Mock the open() function to return a full config file example
         with patch('builtins.open', return_value=StringIO(_FULL_CONFIG)):
+            # The filename is only a placeholder, file content is determined by mocking open
             config = parse_config_file('test')
+        # Make sure all mandatory values are present
         self.assertIn('listen', config)
         self.assertIn('port', config)
         self.assertIn('staticroot', config)
@@ -53,7 +98,7 @@ class TestConfig(TestCase):
         self.assertIn('Name', config['pagelet_variables'])
         self.assertIn('UploadDir', config['pagelet_variables'])
         self.assertIn('DatabaseFile', config['pagelet_variables'])
-
+        # Make sure all values are set as described in the config file
         self.assertEqual('fe80::0123:45ff:fe67:89ab', config['listen'])
         self.assertEqual(8080, config['port'])
         self.assertEqual('/var/test/static', config['staticroot'])
@@ -61,3 +106,31 @@ class TestConfig(TestCase):
         self.assertEqual('Matemat\n(Unit Test)', config['pagelet_variables']['Name'])
         self.assertEqual('/var/test/static/upload', config['pagelet_variables']['UploadDir'])
         self.assertEqual('/var/test/db/test.db', config['pagelet_variables']['DatabaseFile'])
+
+    def test_parse_config_precedence(self):
+        """
+        Test that config items from files with higher precedence replace items with the same key from files with lower
+        precedence.
+        """
+        # Mock the open() function to return a full config file on the first call, and a partial config file on the
+        # second call
+        with patch('builtins.open', return_value=IterOpenMock([_FULL_CONFIG, _PARTIAL_CONFIG])):
+            # These filenames are only placeholders, file content is determined by mocking open
+            config = parse_config_file(['full', 'partial'])
+        # Make sure all mandatory values are present
+        self.assertIn('listen', config)
+        self.assertIn('port', config)
+        self.assertIn('staticroot', config)
+        self.assertIn('templateroot', config)
+        self.assertIn('pagelet_variables', config)
+        self.assertIn('Name', config['pagelet_variables'])
+        self.assertIn('UploadDir', config['pagelet_variables'])
+        self.assertIn('DatabaseFile', config['pagelet_variables'])
+        # Make sure all values are set as described in the config files, values from the partial file take precedence
+        self.assertEqual('fe80::0123:45ff:fe67:89ab', config['listen'])
+        self.assertEqual(443, config['port'])
+        self.assertEqual('/var/test/static', config['staticroot'])
+        self.assertEqual('/var/test/templates', config['templateroot'])
+        self.assertEqual('Matemat (Unit Test 2)', config['pagelet_variables']['Name'])
+        self.assertEqual('/var/test/static/upload', config['pagelet_variables']['UploadDir'])
+        self.assertEqual('/var/test/db/test.db', config['pagelet_variables']['DatabaseFile'])