ldap_sync: Add support for excluding usernames from sync

.pydevproject

 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?eclipse-pydev version="1.0"?><pydev_project>
-<pydev_property name="org.python.pydev.PYTHON_PROJECT_INTERPRETER">django18</pydev_property>
+<pydev_property name="org.python.pydev.PYTHON_PROJECT_INTERPRETER">django-fountain</pydev_property>
 <pydev_property name="org.python.pydev.PYTHON_PROJECT_VERSION">python 2.7</pydev_property>
 <pydev_pathproperty name="org.python.pydev.PROJECT_SOURCE_PATH">
 <path>/${PROJECT_DIR_NAME}</path>

fountain/management/commands/ldap_sync.py

 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
+import re
 from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.core.management.base import BaseCommand
 from fountain.ldap import Ldap
 
-
 class Command(BaseCommand):
+    DEFAULT_EXCLUDE_REGEX = r'^api:'
     help = "Updates the attributes of all Django users from the LDAP server." 
     
+    def add_arguments(self, parser):
+        parser.add_argument('-e', '--exclude',
+                dest='exclude_usernames',
+                metavar='username',
+                nargs='*',
+                help="You can exclude single usernames from the LDAP sync using this switch."
+            )
+        parser.add_argument('-r', '--exclude-regex',
+                default=self.DEFAULT_EXCLUDE_REGEX,
+                dest='exclude_regex',
+                metavar='regex',
+                nargs='?',
+                help="Sometimes you might want to exclude users from LDAP sync,\
+                      such as API users. You may specify a Python regular expression \
+                      here for usernames that you want to ignore during the sync.\n\
+                      Default: \"{}\"".format(self.DEFAULT_EXCLUDE_REGEX),
+            )
+    
     def handle(self, *args, **options):
         verbosity = options.get('verbosity')
         sync_is_active = getattr(settings, 'LDAP_SYNC_IS_ACTIVE', True)
         
+        exclude_regex = options.get('exclude_regex')
+        if exclude_regex:
+            exclude_regex = re.compile(exclude_regex)
+        
+        exclude_usernames = options.get('exclude_usernames')
+        if exclude_usernames:
+            exclude_usernames = set(exclude_usernames)
+        else:
+            exclude_usernames = set()
+        
         User = get_user_model()
         l = Ldap()
         
@@ -23,6 +52,17 @@ class Command(BaseCommand):
 
         for user_dict in User.objects.all().values(*values).iterator():
             username = user_dict[User.USERNAME_FIELD]
+            
+            if username in exclude_usernames:
+                if verbosity > 2:
+                    self.stdout.write('Ignoring {}'.format(username))
+                continue
+            
+            if exclude_regex and exclude_regex.match(username):
+                if verbosity > 2:
+                    self.stdout.write('Ignoring {}'.format(username))
+                continue               
+            
             attrs = l.get_attributes(username)
             if sync_is_active:
                 if attrs:

tests/tests.py

 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
+import StringIO
 import threading
 from django.core import management
 from django.contrib.auth import get_user_model
 from django.test import Client, TestCase
 from .server import get_reactor
+from IPython.utils.io import stdout
 
 class LdapTestCase(TestCase):
     def setUp(self):
@@ -125,6 +127,29 @@ class LdapTestCase(TestCase):
             user = self.USER_MODEL.objects.get(username='not_in_ldap')
             self.assertTrue(user.is_active)
 
+    def test_management_command_exclude_arguments(self):
+        with self.settings(LDAP_SYNC_IS_ACTIVE=True):
+            self.USER_MODEL.objects.create(username='test',  is_active=False)
+            self.USER_MODEL.objects.create(username='alice', is_active=False)
+            self.USER_MODEL.objects.create(username='api:not_in_ldap', is_active=True)
+            
+            # Clear user attributes for this test
+            self.USER_MODEL.objects.all().update(first_name='', last_name='', email='')
+        
+            stdout = StringIO.StringIO()
+        
+            management.call_command('ldap_sync', exclude=['alice'], verbosity=3, stdout=stdout)
+            user = self.USER_MODEL.objects.get(username='test')
+            self.assertTrue(user.is_active)
+            user = self.USER_MODEL.objects.get(username='alice')
+            self.assertFalse(user.is_active)
+            user = self.USER_MODEL.objects.get(username='api:not_in_ldap')
+            self.assertTrue(user.is_active)
+            
+            # Check if output matches
+            output_lines = set(stdout.getvalue().splitlines())
+            self.assertIn("Ignoring api:not_in_ldap", output_lines)
+            self.assertIn("Ignoring alice", output_lines)
     
     def test_invalid_user(self):
         with self.settings():