Add config tree to synapse. Add support for reading config from a file

synapse/config/_base.py

@@ -0,0 +1,99 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 matrix.org
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import ConfigParser as configparser
+import argparse
+import sys
+import os
+
+
+class Config(object):
+    def __init__(self, args):
+        pass
+
+    @staticmethod
+    def read_file(file_path):
+        with open(file_path) as file_stream:
+            return file_stream.read()
+
+    @staticmethod
+    def read_config_file(file_path):
+        config = configparser.SafeConfigParser()
+        config.read([file_path])
+        config_dict = {}
+        for section in config.sections():
+            config_dict.update(config.items(section))
+        return config_dict
+
+    @classmethod
+    def add_arguments(cls, parser):
+        pass
+
+    @classmethod
+    def generate_config(cls, args, config_dir_path):
+        pass
+
+    @classmethod
+    def load_config(cls, description, argv, generate_section=None):
+        config_parser = argparse.ArgumentParser(add_help=False)
+        config_parser.add_argument(
+            "-c", "--config-path",
+            metavar="CONFIG_FILE",
+            help="Specify config file"
+        )
+        config_args, remaining_args = config_parser.parse_known_args(argv)
+
+        if generate_section:
+            if not config_args.config_path:
+                config_parser.error(
+                    "Must specify where to generate the config file"
+                )
+            config_dir_path = os.path.dirname(config_args.config_path)
+            if os.path.exists(config_args.config_path):
+                defaults = cls.read_config_file(config_args.config_path)
+        else:
+            if config_args.config_path:
+                defaults = cls.read_config_file(config_args.config_path)
+            else:
+                defaults = {}
+
+        parser = argparse.ArgumentParser(
+            parents=[config_parser],
+            description=description,
+            formatter_class=argparse.RawDescriptionHelpFormatter,
+        )
+        parser.set_defaults(**defaults)
+
+
+        cls.add_arguments(parser)
+        args = parser.parse_args(remaining_args)
+
+        if generate_section:
+            config_dir_path = os.path.dirname(config_args.config_path)
+            config_dir_path = os.path.abspath(config_dir_path)
+            cls.generate_config(args, config_dir_path)
+            config = configparser.SafeConfigParser()
+            config.add_section(generate_section)
+            for key, value in vars(args).items():
+                if key != "config_path" and value is not None:
+                    config.set(generate_section, key, str(value))
+            with open(config_args.config_path, "w") as config_file:
+                config.write(config_file)
+
+        return cls(args)
+
+
+