cache-events-fix

main.py

@@ -7,6 +7,7 @@ from ariadne.asgi import GraphQL
 from starlette.applications import Starlette
 from starlette.routing import Route
 
+from services.cache import events_register
 from services.rediscache import redis
 from services.schema import resolvers
 from services.viewed import ViewedStorage
@@ -37,6 +38,7 @@ app = Starlette(
         ViewedStorage.init,
         # search_service.info,
         # start_sentry,
+        events_register,
         start,
     ],
     on_shutdown=[redis.disconnect],

resolvers/author.py

@@ -2,7 +2,7 @@ import asyncio
 import json
 import time
 
-from sqlalchemy import select, or_, and_, text, desc, literal
+from sqlalchemy import select, or_, and_, text, desc
 from sqlalchemy.orm import aliased
 from sqlalchemy_searchable import search
 
@@ -52,7 +52,7 @@ async def get_author(_, _info, slug='', author_id=None):
         if author_id:
             cache = await redis.execute('GET', f'id:{author_id}:author')
             logger.debug(f'result from cache: {cache}')
-            q = select(Author).where(Author.id == literal(author_id))
+            q = select(Author).where(Author.id == author_id)
             author_dict = None
             if cache:
                 author_dict = json.loads(cache)

resolvers/follower.py

@@ -2,7 +2,7 @@ import json
 import time
 from typing import List
 
-from sqlalchemy import select, or_, column
+from sqlalchemy import select, or_
 from sqlalchemy.sql import and_
 
 from orm.author import Author, AuthorFollower
@@ -34,7 +34,7 @@ async def follow(_, info, what, slug):
     user_id = info.context.get('user_id')
     if not user_id:
         return {"error": "unauthorized"}
-    [follower] = get_with_stat(select(Author).select_from(Author).filter(column(Author.user) == user_id))
+    [follower] = get_with_stat(select(Author).select_from(Author).filter(Author.user == user_id))
     if not follower:
         return {"error": "cant find follower"}
 
@@ -42,7 +42,7 @@ async def follow(_, info, what, slug):
         error = author_follow(follower.id, slug)
         if not error:
             logger.debug(f'@{follower.slug} followed @{slug}')
-            [author] = get_with_stat(select(Author).select_from(Author).where(column(Author.slug) == slug))
+            [author] = get_with_stat(select(Author).select_from(Author).where(Author.slug == slug))
             if not author:
                 return {"error": "author is not found"}
             follows = await update_follows_for_author(follower, 'author', author.dict(), True)
@@ -52,7 +52,7 @@ async def follow(_, info, what, slug):
     elif what == 'TOPIC':
         error = topic_follow(follower.id, slug)
         if not error:
-            [topic] = get_with_stat(select(Topic).where(column(Topic.slug) == slug))
+            [topic] = get_with_stat(select(Topic).where(Topic.slug == slug))
             if not topic:
                 return {"error": "topic is not found"}
             follows = await update_follows_for_author(follower, 'topic', topic.dict(), True)
@@ -63,7 +63,7 @@ async def follow(_, info, what, slug):
     elif what == 'SHOUT':
         error = reactions_follow(follower.id, slug)
         if not error:
-            [shout] = local_session().execute(select(Shout).where(column(Shout.slug) == slug))
+            [shout] = local_session().execute(select(Shout).where(Shout.slug == slug))
             if not shout:
                 return {"error": "cant find shout"}
             follows = await update_follows_for_author(follower, 'shout', shout.dict(), True)
@@ -79,7 +79,7 @@ async def unfollow(_, info, what, slug):
     user_id = info.context.get('user_id')
     if not user_id:
         return {"error": "unauthorized"}
-    follower_query = select(Author).filter(column(Author.user) == user_id)
+    follower_query = select(Author).filter(Author.user == user_id)
     [follower] = get_with_stat(follower_query)
     if not follower:
         return {"error": "follower profile is not found"}
@@ -88,7 +88,7 @@ async def unfollow(_, info, what, slug):
         error = author_unfollow(follower.id, slug)
         if not error:
             logger.info(f'@{follower.slug} unfollowing @{slug}')
-            [author] = get_with_stat(select(Author).where(column(Author.slug) == slug))
+            [author] = get_with_stat(select(Author).where(Author.slug == slug))
             if not author:
                 return {"error": "cant find author"}
             _followers = await update_followers_for_author(follower, author, False)
@@ -99,7 +99,7 @@ async def unfollow(_, info, what, slug):
         error = topic_unfollow(follower.id, slug)
         if not error:
             logger.info(f'@{follower.slug} unfollowing §{slug}')
-            [topic] = get_with_stat(select(Topic).where(column(Topic.slug) == slug))
+            [topic] = get_with_stat(select(Topic).where(Topic.slug == slug))
             if not topic:
                 return {"error": "cant find topic"}
             follows = await update_follows_for_author(follower, 'topic', topic.dict(), False)
@@ -111,7 +111,7 @@ async def unfollow(_, info, what, slug):
         error = reactions_unfollow(follower.id, slug)
         if not error:
             logger.info(f'@{follower.slug} unfollowing §{slug}')
-            [shout] = local_session().execute(select(Shout).where(column(Shout.slug) == slug))
+            [shout] = local_session().execute(select(Shout).where(Shout.slug == slug))
             if not shout:
                 return {"error": "cant find shout"}
             if not error:
@@ -276,8 +276,8 @@ def author_unfollow(follower_id, slug):
 def get_topic_followers(_, _info, slug: str, topic_id: int) -> List[Author]:
     q = select(Author)
     q = (
-        q.join(TopicFollower, column(TopicFollower.follower) == Author.id)
+        q.join(TopicFollower, TopicFollower.follower == Author.id)
-        .join(Topic, column(Topic.id) == column(TopicFollower.topic))
+        .join(Topic, Topic.id == TopicFollower.topic)
         .filter(or_(Topic.slug == slug, Topic.id == topic_id))
     )
     return get_with_stat(q)

resolvers/stat.py

@@ -6,6 +6,7 @@ from orm.topic import TopicFollower, Topic
 from services.db import local_session
 from orm.author import AuthorFollower, Author, AuthorRating
 from orm.shout import ShoutTopic, ShoutAuthor, Shout
+from services.logger import root_logger as logger
 
 
 def add_topic_stat_columns(q):
@@ -16,26 +17,26 @@ def add_topic_stat_columns(q):
     q = (
         q.outerjoin(aliased_shout_topic, aliased_shout_topic.topic == Topic.id)
         .add_columns(
-            func.count(distinct(aliased_shout_topic.shout)).label('shouts_stat')
+            func.count(distinct(aliased_shout_topic.shout)).label("shouts_stat")
         )
         .outerjoin(
             aliased_shout_author,
             aliased_shout_topic.shout == aliased_shout_author.shout,
         )
         .add_columns(
-            func.count(distinct(aliased_shout_author.author)).label('authors_stat')
+            func.count(distinct(aliased_shout_author.author)).label("authors_stat")
         )
         .outerjoin(aliased_topic_follower)
         .add_columns(
             func.count(distinct(aliased_topic_follower.follower)).label(
-                'followers_stat'
+                "followers_stat"
             )
         )
     )
     # Create a subquery for comments count
     _sub_comments = (
         select(
-            Shout.id, func.coalesce(func.count(Reaction.id), 0).label('comments_count')
+            Shout.id, func.coalesce(func.count(Reaction.id), 0).label("comments_count")
         )
         .join(
             Reaction,
@@ -66,23 +67,23 @@ def add_author_stat_columns(q):
 
     q = q.outerjoin(aliased_shout_author, aliased_shout_author.author == Author.id)
     q = q.add_columns(
-        func.count(distinct(aliased_shout_author.shout)).label('shouts_stat')
+        func.count(distinct(aliased_shout_author.shout)).label("shouts_stat")
     )
 
     q = q.outerjoin(aliased_authors, aliased_authors.follower == Author.id)
     q = q.add_columns(
-        func.count(distinct(aliased_authors.author)).label('authors_stat')
+        func.count(distinct(aliased_authors.author)).label("authors_stat")
     )
 
     q = q.outerjoin(aliased_followers, aliased_followers.author == Author.id)
     q = q.add_columns(
-        func.count(distinct(aliased_followers.follower)).label('followers_stat')
+        func.count(distinct(aliased_followers.follower)).label("followers_stat")
     )
 
     # Create a subquery for comments count
     sub_comments = (
         select(
-            Author.id, func.coalesce(func.count(Reaction.id), 0).label('comments_stat')
+            Author.id, func.coalesce(func.count(Reaction.id), 0).label("comments_stat")
         )
         .outerjoin(
             Reaction,
@@ -99,23 +100,10 @@ def add_author_stat_columns(q):
     q = q.outerjoin(sub_comments, Author.id == sub_comments.c.id)
     q = q.add_columns(sub_comments.c.comments_stat)
 
-    # Create a subquery for topics
+    q = q.group_by(
-    _sub_topics = (
+        Author.id, sub_comments.c.comments_stat
-        select(
-            ShoutAuthor.author,
-            func.count(distinct(ShoutTopic.topic)).label('topics_stat'),
-        )
-        .join(Shout, ShoutTopic.shout == Shout.id)
-        .join(ShoutAuthor, Shout.id == ShoutAuthor.shout)
-        .group_by(ShoutAuthor.author)
-        .subquery()
     )
 
-    # q = q.outerjoin(sub_topics, Author.id == sub_topics.c.author)
-    # q = q.add_columns(sub_topics.c.topics_stat)
-
-    q = q.group_by(Author.id, sub_comments.c.comments_stat)  #, sub_topics.c.topics_stat)
-
     return q
 
 
@@ -124,7 +112,7 @@ def add_author_ratings(q):
     ratings_subquery = (
         select(
             [
-                aliased_author.id.label('author_id'),
+                aliased_author.id.label("author_id"),
                 func.count()
                 .filter(
                     and_(
@@ -133,12 +121,12 @@ def add_author_ratings(q):
                         Reaction.deleted_at.is_(None),
                     )
                 )
-                .label('comments_count'),
+                .label("comments_count"),
                 func.sum(case((AuthorRating.plus == true(), 1), else_=0)).label(
-                    'likes_count'
+                    "likes_count"
                 ),
                 func.sum(case((AuthorRating.plus != true(), 1), else_=0)).label(
-                    'dislikes_count'
+                    "dislikes_count"
                 ),
                 func.sum(
                     case(
@@ -151,7 +139,7 @@ def add_author_ratings(q):
                         ),
                         else_=0,
                     )
-                ).label('shouts_likes'),
+                ).label("shouts_likes"),
                 func.sum(
                     case(
                         (
@@ -163,7 +151,7 @@ def add_author_ratings(q):
                         ),
                         else_=0,
                     )
-                ).label('shouts_dislikes'),
+                ).label("shouts_dislikes"),
             ]
         )
         .select_from(aliased_author)
@@ -171,42 +159,47 @@ def add_author_ratings(q):
         .outerjoin(Shout, Shout.authors.any(id=aliased_author.id))
         .filter(Reaction.deleted_at.is_(None))
         .group_by(aliased_author.id)
-        .alias('ratings_subquery')
+        .alias("ratings_subquery")
     )
 
     return q.join(ratings_subquery, Author.id == ratings_subquery.c.author_id)
 
 
 def get_with_stat(q):
-    is_author = f'{q}'.lower().startswith('select author')
+    try:
-    is_topic = f'{q}'.lower().startswith('select topic')
+        is_author = f"{q}".lower().startswith("select author")
-    if is_author:
+        is_topic = f"{q}".lower().startswith("select topic")
-        q = add_author_stat_columns(q)
+        if is_author:
-        # q = add_author_ratings(q)  # TODO: move rating to cols down there
+            q = add_author_stat_columns(q)
-    elif is_topic:
+            # q = add_author_ratings(q)  # TODO: move rating to cols down there
-        q = add_topic_stat_columns(q)
+        elif is_topic:
-    records = []
+            q = add_topic_stat_columns(q)
-    # logger.debug(f'{q}'.replace('\n', ' '))
+        records = []
-    with local_session() as session:
+        # logger.debug(f'{q}'.replace('\n', ' '))
-        for cols in session.execute(q):
+        with local_session() as session:
-            entity = cols[0]
+            for cols in session.execute(q):
-            entity.stat = {}
+                entity = cols[0]
-            entity.stat['shouts'] = cols[1]
+                if not isinstance(entity, dict):
-            entity.stat['authors'] = cols[2]
+                    entity = entity.dict()
-            entity.stat['followers'] = cols[3]
+                stat = dict()
-            if is_author:
+                stat["shouts"] = cols[1]
-                entity.stat['comments'] = cols[4]
+                stat["authors"] = cols[2]
-                # entity.stat['topics'] = cols[5]
+                stat["followers"] = cols[3]
-                # entity.stat['rating'] = cols[5] - cols[6]
+                if is_author:
-                # entity.stat['rating_shouts'] = cols[7] - cols[8]
+                    stat["comments"] = cols[4]
-
+                    # entity.stat['topics'] = cols[5]
-            records.append(entity)
+                    # entity.stat['rating'] = cols[5] - cols[6]
-
+                    # entity.stat['rating_shouts'] = cols[7] - cols[8]
+                entity['stat'] = stat
+                records.append(entity)
+    except Exception as exc:
+        logger.debug(cols)
+        raise Exception(exc)
     return records
 
 
 def author_follows_authors(author_id: int):
-    af = aliased(AuthorFollower, name='af')
+    af = aliased(AuthorFollower, name="af")
     q = (
         select(Author)
         .select_from(join(Author, af, Author.id == af.author))

services/cache.py

@@ -14,27 +14,33 @@ from services.logger import root_logger as logger
 
 
 DEFAULT_FOLLOWS = {
-    'topics': [],
+    "topics": [],
-    'authors': [],
+    "authors": [],
-    'communities': [{'id': 1, 'name': 'Дискурс', 'slug': 'discours', 'pic': ''}],
+    "communities": [{"id": 1, "name": "Дискурс", "slug": "discours", "pic": ""}],
 }
 
 
 async def set_author_cache(author: dict):
     payload = json.dumps(author, cls=CustomJSONEncoder)
-    await redis.execute('SET', f'user:{author.get("user")}:author', payload)
+    await redis.execute("SET", f'user:{author.get("user")}:author', payload)
-    await redis.execute('SET', f'id:{author.get("id")}:author', payload)
+    await redis.execute("SET", f'id:{author.get("id")}:author', payload)
 
 
 async def update_author_followers_cache(author_id: int, followers):
-    payload = json.dumps([f.dict() if isinstance(f, Author) else f for f in followers], cls=CustomJSONEncoder)
+    payload = json.dumps(
-    await redis.execute('SET', f'author:{author_id}:followers', payload)
+        [f.dict() if isinstance(f, Author) else f for f in followers],
+        cls=CustomJSONEncoder,
+    )
+    await redis.execute("SET", f"author:{author_id}:followers", payload)
 
 
 async def set_follows_topics_cache(follows, author_id: int):
     try:
-        payload = json.dumps([a.dict() if isinstance(a, Author) else a for a in follows], cls=CustomJSONEncoder)
+        payload = json.dumps(
-        await redis.execute('SET', f'author:{author_id}:follows-topics', payload)
+            [a.dict() if isinstance(a, Author) else a for a in follows],
+            cls=CustomJSONEncoder,
+        )
+        await redis.execute("SET", f"author:{author_id}:follows-topics", payload)
     except Exception as exc:
         logger.error(exc)
         import traceback
@@ -45,8 +51,11 @@ async def set_follows_topics_cache(follows, author_id: int):
 
 async def set_follows_authors_cache(follows, author_id: int):
     try:
-        payload = json.dumps([a.dict() if isinstance(a, Author) else a for a in follows], cls=CustomJSONEncoder)
+        payload = json.dumps(
-        await redis.execute('SET', f'author:{author_id}:follows-authors', payload)
+            [a.dict() if isinstance(a, Author) else a for a in follows],
+            cls=CustomJSONEncoder,
+        )
+        await redis.execute("SET", f"author:{author_id}:follows-authors", payload)
     except Exception as exc:
         import traceback
 
@@ -59,22 +68,22 @@ async def update_follows_for_author(
     follower: Author, entity_type: str, entity: dict, is_insert: bool
 ):
     follows = []
-    redis_key = f'author:{follower.id}:follows-{entity_type}s'
+    redis_key = f"author:{follower.id}:follows-{entity_type}s"
-    follows_str = await redis.execute('GET', redis_key)
+    follows_str = await redis.execute("GET", redis_key)
     if isinstance(follows_str, str):
         follows = json.loads(follows_str)
     if is_insert:
         follows.append(entity)
     else:
-        entity_id = entity.get('id')
+        entity_id = entity.get("id")
         if not entity_id:
-            raise Exception('wrong entity')
+            raise Exception("wrong entity")
         # Remove the entity from follows
-        follows = [e for e in follows if e['id'] != entity_id]
+        follows = [e for e in follows if e["id"] != entity_id]
         logger.debug(f'{entity['slug']} removed from what @{follower.slug} follows')
-    if entity_type == 'topic':
+    if entity_type == "topic":
         await set_follows_topics_cache(follows, follower.id)
-    if entity_type == 'author':
+    if entity_type == "author":
         await set_follows_authors_cache(follows, follower.id)
     return follows
 
@@ -82,8 +91,8 @@ async def update_follows_for_author(
 async def update_followers_for_author(
     follower: Author, author: Author, is_insert: bool
 ):
-    redis_key = f'author:{author.id}:followers'
+    redis_key = f"author:{author.id}:followers"
-    followers_str = await redis.execute('GET', redis_key)
+    followers_str = await redis.execute("GET", redis_key)
     followers = []
     if isinstance(followers_str, str):
         followers = json.loads(followers_str)
@@ -91,14 +100,12 @@ async def update_followers_for_author(
         followers.append(follower)
     else:
         # Remove the entity from followers
-        followers = [e for e in followers if e['id'] != author.id]
+        followers = [e for e in followers if e["id"] != author.id]
     await update_author_followers_cache(author.id, followers)
     return followers
 
 
-@event.listens_for(Shout, 'after_insert')
+def after_shout_update(_mapper, _connection, shout: Shout):
-@event.listens_for(Shout, 'after_update')
-def after_shouts_update(_mapper, _connection, shout: Shout):
     # Main query to get authors associated with the shout through ShoutAuthor
     authors_query = (
         select(Author)
@@ -111,8 +118,7 @@ def after_shouts_update(_mapper, _connection, shout: Shout):
         asyncio.create_task(set_author_cache(author_with_stat.dict()))
 
 
-@event.listens_for(Reaction, 'after_insert')
+def after_reaction_update(mapper, connection, reaction: Reaction):
-def after_reaction_insert(mapper, connection, reaction: Reaction):
     try:
         author_subquery = select(Author).where(Author.id == reaction.created_by)
         replied_author_subquery = (
@@ -122,20 +128,11 @@ def after_reaction_insert(mapper, connection, reaction: Reaction):
         )
 
         author_query = (
-            select(
+            select(author_subquery.subquery())
-                author_subquery.subquery().c.id,
-                author_subquery.subquery().c.slug,
-                author_subquery.subquery().c.created_at,
-                author_subquery.subquery().c.name,
-            )
             .select_from(author_subquery.subquery())
             .union(
-                select(
+                select(replied_author_subquery.subquery())
-                    replied_author_subquery.subquery().c.id,
+                .select_from(replied_author_subquery.subquery())
-                    replied_author_subquery.subquery().c.slug,
-                    replied_author_subquery.subquery().c.created_at,
-                    replied_author_subquery.subquery().c.name,
-                ).select_from(replied_author_subquery.subquery())
             )
         )
 
@@ -146,15 +143,14 @@ def after_reaction_insert(mapper, connection, reaction: Reaction):
             select(Shout).select_from(Shout).where(Shout.id == reaction.shout)
         ).first()
         if shout:
-            after_shouts_update(mapper, connection, shout)
+            after_shout_update(mapper, connection, shout)
     except Exception as exc:
         logger.error(exc)
         import traceback
+
         traceback.print_exc()
 
 
-@event.listens_for(Author, 'after_insert')
-@event.listens_for(Author, 'after_update')
 def after_author_update(_mapper, _connection, author: Author):
     q = select(Author).where(Author.id == author.id)
     result = get_with_stat(q)
@@ -163,35 +159,33 @@ def after_author_update(_mapper, _connection, author: Author):
         asyncio.create_task(set_author_cache(author_with_stat.dict()))
 
 
-@event.listens_for(TopicFollower, 'after_insert')
 def after_topic_follower_insert(_mapper, _connection, target: TopicFollower):
     asyncio.create_task(
         handle_topic_follower_change(target.topic, target.follower, True)
     )
 
 
-@event.listens_for(TopicFollower, 'after_delete')
 def after_topic_follower_delete(_mapper, _connection, target: TopicFollower):
     asyncio.create_task(
         handle_topic_follower_change(target.topic, target.follower, False)
     )
 
 
-@event.listens_for(AuthorFollower, 'after_insert')
 def after_author_follower_insert(_mapper, _connection, target: AuthorFollower):
     asyncio.create_task(
         handle_author_follower_change(target.author, target.follower, True)
     )
 
 
-@event.listens_for(AuthorFollower, 'after_delete')
 def after_author_follower_delete(_mapper, _connection, target: AuthorFollower):
     asyncio.create_task(
         handle_author_follower_change(target.author, target.follower, False)
     )
 
 
-async def handle_author_follower_change(author_id: int, follower_id: int, is_insert: bool):
+async def handle_author_follower_change(
+    author_id: int, follower_id: int, is_insert: bool
+):
     author_query = select(Author).select_from(Author).filter(Author.id == author_id)
     [author] = get_with_stat(author_query)
     follower_query = select(Author).select_from(Author).filter(Author.id == follower_id)
@@ -199,30 +193,32 @@ async def handle_author_follower_change(author_id: int, follower_id: int, is_ins
     if follower and author:
         _ = asyncio.create_task(set_author_cache(author.dict()))
         follows_authors = await redis.execute(
-            'GET', f'author:{follower_id}:follows-authors'
+            "GET", f"author:{follower_id}:follows-authors"
         )
         if follows_authors:
             follows_authors = json.loads(follows_authors)
-            if not any(x.get('id') == author.id for x in follows_authors):
+            if not any(x.get("id") == author.id for x in follows_authors):
                 follows_authors.append(author.dict())
         _ = asyncio.create_task(set_follows_authors_cache(follows_authors, follower_id))
         _ = asyncio.create_task(set_author_cache(follower.dict()))
         await update_follows_for_author(
             follower,
-            'author',
+            "author",
             {
-                'id': author.id,
+                "id": author.id,
-                'name': author.name,
+                "name": author.name,
-                'slug': author.slug,
+                "slug": author.slug,
-                'pic': author.pic,
+                "pic": author.pic,
-                'bio': author.bio,
+                "bio": author.bio,
-                'stat': author.stat,
+                "stat": author.stat,
             },
             is_insert,
         )
 
 
-async def handle_topic_follower_change(topic_id: int, follower_id: int, is_insert: bool):
+async def handle_topic_follower_change(
+    topic_id: int, follower_id: int, is_insert: bool
+):
     topic_query = select(Topic).filter(Topic.id == topic_id)
     [topic] = get_with_stat(topic_query)
     follower_query = select(Author).filter(Author.id == follower_id)
@@ -230,22 +226,41 @@ async def handle_topic_follower_change(topic_id: int, follower_id: int, is_inser
     if follower and topic:
         _ = asyncio.create_task(set_author_cache(follower.dict()))
         follows_topics = await redis.execute(
-            'GET', f'author:{follower_id}:follows-topics'
+            "GET", f"author:{follower_id}:follows-topics"
         )
         if follows_topics:
             follows_topics = json.loads(follows_topics)
-            if not any(x.get('id') == topic.id for x in follows_topics):
+            if not any(x.get("id") == topic.id for x in follows_topics):
                 follows_topics.append(topic)
         _ = asyncio.create_task(set_follows_topics_cache(follows_topics, follower_id))
         await update_follows_for_author(
             follower,
-            'topic',
+            "topic",
             {
-                'id': topic.id,
+                "id": topic.id,
-                'title': topic.title,
+                "title": topic.title,
-                'slug': topic.slug,
+                "slug": topic.slug,
-                'body': topic.body,
+                "body": topic.body,
-                'stat': topic.stat,
+                "stat": topic.stat,
             },
             is_insert,
         )
+
+
+def events_register():
+    event.listen(Shout, "after_insert", after_shout_update)
+    event.listen(Shout, "after_update", after_shout_update)
+
+    event.listen(Reaction, "after_insert", after_reaction_update)
+    event.listen(Reaction, "after_update", after_reaction_update)
+
+    event.listen(Author, "after_insert", after_author_update)
+    event.listen(Author, "after_update", after_author_update)
+
+    event.listen(AuthorFollower, "after_insert", after_author_follower_insert)
+    event.listen(AuthorFollower, "after_delete", after_author_follower_delete)
+
+    event.listen(TopicFollower, "after_insert", after_topic_follower_insert)
+    event.listen(TopicFollower, "after_delete", after_topic_follower_delete)
+
+    logger.info('cache events were registered!')