Added p.a.users.add_user_to_group() function

pillar/api/users/__init__.py

@@ -1,6 +1,43 @@
+import logging
+
+import bson
+from flask import current_app
+
 from . import hooks
 from .routes import blueprint_api
 
+log = logging.getLogger(__name__)
+
+
+def add_user_to_group(user_id: bson.ObjectId, group_id: bson.ObjectId):
+    """Makes the user member of the given group.
+    
+    Directly uses MongoDB, so that it doesn't require any special permissions.
+    """
+
+    from pymongo.results import UpdateResult
+
+    assert isinstance(user_id, bson.ObjectId)
+    assert isinstance(group_id, bson.ObjectId)
+
+    log.info('Adding user %s to group %s', user_id, group_id)
+
+    users_coll = current_app.db('users')
+    db_user = users_coll.find_one(user_id, projection={'groups': 1})
+    if db_user is None:
+        raise ValueError('user %s not found', user_id, group_id)
+
+    groups = set(db_user.get('groups', []))
+    groups.add(group_id)
+
+    # Sort the groups so that we have predictable, repeatable results.
+    result: UpdateResult = users_coll.update_one(
+        {'_id': db_user['_id']},
+        {'$set': {'groups': sorted(groups)}})
+
+    if result.matched_count == 0:
+        raise ValueError('Unable to add user %s to group %s; user not found.')
+
 
 def setup_app(app, api_prefix):
     app.on_pre_GET_users += hooks.check_user_access