Separate base_url and endpoint

This should fix #1.

example_config.ini

 [DEFAULT]
-endpoint = www-net.scc.kit.edu
+endpoint = prod
 
-[www-net-devel.scc.kit.edu]
+[dev]
+base_url = www-net-devel.scc.kit.edu
 version = 3.0
 token = <token>
 
-[www-net-test.scc.kit.edu]
+[test]
+base_url = www-net-test.scc.kit.edu
 version = 3.0
 token = <token>
 
-[www-net.scc.kit.edu]
+[prod]
+base_url = www-net.scc.kit.edu
 version = 3.0
 token = <token>

netdb_client/util.py

@@ -25,10 +25,14 @@ class ArgumentParser(argparse.ArgumentParser):
         self.add_argument('--auth-config',
                           default=os.path.expanduser('~/.config/netdb_client.ini'),
                           help='config file path (default: %(default)s)')
+        self.add_argument('--endpoint', '-e',
+                          help='endpoint to use.\n'
+                               'Environment: "NETDB_ENDPOINT"\n'
+                               'Config: [DEFAULT]: endpoint')
         self.add_argument('--base-url', '-b',
                           help='webapi server.\n'
                                'Environment: "NETDB_BASE_URL"\n'
-                               'Config: [DEFAULT]: endpoint')
+                               'Config: [$endpoint]: base_url')
         self.add_argument('--version',
                           help='webapi version.\n'
                                'Environment: "NETDB_VERSION"\n'
@@ -47,23 +51,42 @@ class ArgumentParser(argparse.ArgumentParser):
                 self.error(f"Config file is readable by others. Please set it at least to 660.")
             config.read(configpath)
 
-        def load_configoption(option):
-            if getattr(args, option) is None:
-                setattr(args, option, os.getenv(f'NETDB_{option.upper()}', None))
-                if getattr(args, option) is None:
-                    if option == 'base_url':
-                        setattr(args, option, config.get('DEFAULT', 'endpoint', fallback=None))
-                    else:
-                        setattr(args, option, config.get(args.base_url, option, fallback=None))
-                    if getattr(args, option) is None:
-                        self.error(
-                            f'No {option} specified (looked in args, environment variable '
-                            f'"NETDB_{option.upper()}", config-file in "{args.auth_config}")'
-                        )
-
-        # load base_url first!
-        for configoption in ['base_url', 'token', 'version']:
-            load_configoption(configoption)
+        def load_config(option):
+            """load config for an option"""
+
+            # if value is already set, we can stop here
+            if getattr(args, option) is not None:
+                return
+
+            # try to load option from environment
+            value = os.getenv(f'NETDB_{option.upper()}', None)
+
+            if value is None:
+                # endpoint should be loaded from DEFAULT section
+                if option == 'endpoint':
+                    section = 'DEFAULT'
+                # everything else loads from the $endpoint section
+                else:
+                    section = getattr(args, 'endpoint')
+                # load value from config section
+                value = config.get(section, option, fallback=None)
+
+            # For backwards compatibility:
+            # if base_url is still unknown use endpoint instead
+            if option == 'base_url' and value is None:
+                value = section
+
+            if value is None:
+                self.error(
+                    f'No {option} specified (looked in args, environment variable '
+                    f'"NETDB_{option.upper()}", config-file in "{args.auth_config} section {section}")')
+
+            # we have a value now and can use it
+            setattr(args, option, value)
+
+        # start with endpoint to get the right config section
+        for option in ['endpoint', 'base_url', 'token', 'version']:
+            load_config(option)
 
         return args