email: Address some code review comments

- __init__.py: Changed email server description
- audit module: Added module docstring
- email_server action:
  - Used argparse
  - Replaced "wrapper functions" with a getattr based lookup method

actions/email_server

@@ -1,12 +1,11 @@
 #!/usr/bin/python3
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
+import argparse
 import logging
 import os
 import sys
 
-import plinth.modules.email_server.audit as audit
-
 logger = logging.getLogger(__name__)
 
 EXIT_SYNTAX = 10
@@ -23,23 +22,29 @@ def reserved_for_root(fun):
 
 
 def main():
-    if len(sys.argv) != 3:
-        sys.exit(EXIT_SYNTAX)
-    if sys.argv[1] != 'ipc':
-        sys.exit(EXIT_SYNTAX)
-
-    function_name = 'ipc_' + sys.argv[2]
-    globals()[function_name]()
+    parser = argparse.ArgumentParser()
+    parser.add_argument('ipc', nargs=3)
+    arguments = parser.parse_args()
+    subcommand_ipc(arguments)
 
 
 @reserved_for_root
-def ipc_set_sasl():
-    audit.ldap.action_set_sasl()
+def subcommand_ipc(arguments):
+    import plinth.modules.email_server.audit as audit
 
+    _, module_name, action_name = arguments.ipc
+    # We only run actions defined in the audit module
+    if module_name not in audit.__all__:
+        logger.critical('Bad module name: %r', module_name)
+        sys.exit(EXIT_SYNTAX)
 
-@reserved_for_root
-def ipc_set_submission():
-    audit.ldap.action_set_submission()
+    module = getattr(audit, module_name)
+    function = getattr(module, 'action_' + action_name, None)
+    if function is None:
+        logger.critical('Bad action: %s/%r', module_name, action_name)
+        sys.exit(EXIT_SYNTAX)
+
+    function()
 
 
 if __name__ == '__main__':

plinth/modules/email_server/__init__.py

@@ -33,7 +33,7 @@ class EmailServerApp(plinth.app.App):
             app_id=self.app_id,
             version=version,
             name=_('Email Server'),
-            short_description=_('An email server for FreedomBox'),
+            short_description=_('Powered by Postfix, Dovecot & Rspamd'),
             manual_page='EmailServer',
             clients=manifest.clients,
             donation_url='https://freedomboxfoundation.org/donate/'

plinth/modules/email_server/audit/__init__.py

@@ -1,4 +1,8 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Provides diagnosis and repair of email server configuration issues
+"""
+
 from . import ldap
 from . import domain
 

plinth/modules/email_server/audit/ldap.py

@@ -64,13 +64,11 @@ def repair():
     POST /audit/ldap/repair
     """
     logger.debug('Updating postconf: %r', default_config)
-    actions.superuser_run('email_server', ['ipc', 'set_sasl'])
+    actions.superuser_run('email_server', ['ipc', 'ldap', 'set_sasl'])
 
-    logger.debug('Setting up postfix %s service in master.cf: %r',
-                 submission_flags.service, default_submission_options)
-    logger.debug('And postfix %s service: %r', smtps_flags.service,
-                 default_smtps_options)
-    actions.superuser_run('email_server', ['ipc', 'set_submission'])
+    logger.debug('Setting up postfix services:\n    %r\n    %r',
+                 default_submission_options, default_smtps_options)
+    actions.superuser_run('email_server', ['ipc', 'ldap', 'set_submission'])
 
 
 def action_set_sasl():