def unfollow(cls, from_user_id, to_user_id):
if from_user_id == to_user_id:
return 0
# Queryset 的 delete 操作返回两个值，一个是删了多少数据，一个是具体每种类型删了多少
# 为什么会出现多种类型数据的删掉？因为可能因为 foreign key 设置了 cascade 出现级联
# 删除，也就是比如 A model 的某个属性是 B model 的 foreign key，并且设置了
# on_delete = models.CASCADE，那么当 B 的某个数据被删除的时候，A 中的关联也会被删除。
# 所以 CASCADE 是很危险的，一般最好不要用，而是用 on_delete = models.SET_NULL
# 取而代之，这样至少可以避免误删除操作带来的多米诺效应
if not GateKeeper.is_switch_on('switch_friendship_to_hbase'):
deleted, _ = Friendship.objects.filter(
from_user_id=from_user_id,
to_user_id=to_user_id,
).delete()
return deleted
instance = cls.get_follow_instance(from_user_id, to_user_id)
if instance is None:
return 0
HBaseFollowing.delete(from_user_id=from_user_id,
created_at=instance.created_at)
HBaseFollower.delete(to_user_id=to_user_id,
created_at=instance.created_at)
return 1
def get_following_user_id_set(cls, from_user_id):
if not GateKeeper.is_switch_on('switch_friendship_to_hbase'):
friendships = Friendship.objects.filter(from_user_id=from_user_id)
else:
friendships = HBaseFollowing.filter(prefix=(from_user_id, ))
user_id_set = set([fs.to_user_id for fs in friendships])
return user_id_set
def test_save_and_get(self):
timestamp = self.ts_now
following = HBaseFollowing(from_user_id=123, to_user_id=34, created_at=timestamp)
following.save()
instance = HBaseFollowing.get(from_user_id=123, created_at=timestamp)
self.assertEqual(instance.from_user_id, 123)
self.assertEqual(instance.to_user_id, 34)
self.assertEqual(instance.created_at, timestamp)
following.to_user_id = 456
following.save()
instance = HBaseFollowing.get(from_user_id=123, created_at=timestamp)
self.assertEqual(instance.to_user_id, 456)
# object does not exist, return None
instance = HBaseFollowing.get(from_user_id=123, created_at=self.ts_now)
self.assertEqual(instance, None)
def unfollow(cls, from_user_id, to_user_id):
if from_user_id == to_user_id:
return 0
if not GateKeeper.is_switch_on('switch_friendship_to_hbase'):
deleted, _ = Friendship.objects.filter(
from_user_id=from_user_id,
to_user_id=to_user_id,
).delete()
return deleted
instance = cls.get_follow_instance(from_user_id, to_user_id)
if instance is None:
return 0
HBaseFollowing.delete(from_user_id=from_user_id,
created_at=instance.created_at)
HBaseFollower.delete(to_user_id=to_user_id,
created_at=instance.created_at)
return 1
def get_following_user_id_set(cls, from_user_id):
key = FOLLOWING_PATTERN.format(user_id=from_user_id)
user_id_set = cache.get(key)
# set exists in cache
if user_id_set is not None:
return user_id_set
# set doesn't exist in cache, build one from the DB
if GateKeeper.is_switch_on('switch_friendship_to_hbase'):
friendships = HBaseFollowing.filter(prefix=(from_user_id, None))
else:
friendships = Friendship.objects.filter(from_user_id=from_user_id)
user_id_set = set([fs.to_user_id for fs in friendships])
cache.set(key, user_id_set) # save in cache
return user_id_set
def unfollow(cls, from_user_id, to_user_id):
if from_user_id == to_user_id:
return 0
if not GateKeeper.is_switch_on('switch_friendship_to_hbase'):
delete, _ = Friendship.objects.filter(
from_user_id=from_user_id,
to_user_id=to_user_id,
).delete()
return delete
following = cls.get_following_instance(from_user_id=from_user_id,
to_user_id=to_user_id)
# fs = HBaseFollowing.filter(prefix=(from_user_id, None))
# for f in fs:
# print(f.from_user_id, f.created_at, '->', f.to_user_id)
# print(following)
if following is None:
return 0
HBaseFollowing.delete(from_user_id=from_user_id,
created_at=following.created_at)
HBaseFollower.delete(to_user_id=to_user_id,
created_at=following.created_at)
return 1
def follow(cls, from_user_id, to_user_id):
if from_user_id == to_user_id:
return None
if not GateKeeper.is_switch_on('switch_friendship_to_hbase'):
return Friendship.objects.create(
from_user_id=from_user_id,
to_user_id=to_user_id,
)
now = ts_now_as_int()
HBaseFollower.create(
from_user_id=from_user_id,
created_at=now,
to_user_id=to_user_id,
)
return HBaseFollowing.create(
from_user_id=from_user_id,
created_at=now,
to_user_id=to_user_id,
)
def follow(cls, from_user_id, to_user_id):
if from_user_id == to_user_id:
return None
if not GateKeeper.is_switch_on('switch_friendship_to_hbase'):
# create data in mysql
return Friendship.objects.create(
from_user_id=from_user_id,
to_user_id=to_user_id,
)
# create data in hbase
now = int(time.time() * 1000000)
HBaseFollower.create(
from_user_id=from_user_id,
to_user_id=to_user_id,
created_at=now,
)
return HBaseFollowing.create(
from_user_id=from_user_id,
to_user_id=to_user_id,
created_at=now,
)
def get_following_count(cls, from_user_id):
if not GateKeeper.is_switch_on('switch_friendship_to_hbase'):
return Friendship.objects.filter(from_user_id=from_user_id).count()
followings = HBaseFollowing.filter(prefix=(from_user_id, ))
return len(followings)
def get_follow_instance(cls, from_user_id, to_user_id):
followings = HBaseFollowing.filter(prefix=(from_user_id, ))
for follow in followings:
if follow.to_user_id == to_user_id:
return follow
return None
from friendships.hbase_models import HBaseFollowing
table = HBaseFollowing.get_table()
def print_rows(rows):
for row_key, row_data in rows:
print(row_key, row_data)
# rows = table.scan()
rows = table.scan(row_stop=b'1000000000000000:1629391756362040',
limit=2,
reverse=True)
#rows = table.scan(row_prefix=b'1000000000000000', limit=3)
print_rows(rows)
def test_filter(self):
HBaseFollowing.create(from_user_id=1,
to_user_id=2,
created_at=self.ts_now)
HBaseFollowing.create(from_user_id=1,
to_user_id=3,
created_at=self.ts_now)
HBaseFollowing.create(from_user_id=1,
to_user_id=4,
created_at=self.ts_now)
followings = HBaseFollowing.filter(prefix=(1, None))
self.assertEqual(3, len(followings))
self.assertEqual(followings[0].from_user_id, 1)
self.assertEqual(followings[0].to_user_id, 2)
self.assertEqual(followings[1].from_user_id, 1)
self.assertEqual(followings[1].to_user_id, 3)
self.assertEqual(followings[2].from_user_id, 1)
self.assertEqual(followings[2].to_user_id, 4)
# test limit
results = HBaseFollowing.filter(prefix=(1, None), limit=1)
self.assertEqual(len(results), 1)
self.assertEqual(results[0].to_user_id, 2)
results = HBaseFollowing.filter(prefix=(1, None), limit=2)
self.assertEqual(len(results), 2)
self.assertEqual(results[0].to_user_id, 2)
self.assertEqual(results[1].to_user_id, 3)
results = HBaseFollowing.filter(prefix=(1, None), limit=4)
self.assertEqual(len(results), 3)
self.assertEqual(results[0].to_user_id, 2)
self.assertEqual(results[1].to_user_id, 3)
self.assertEqual(results[2].to_user_id, 4)
results = HBaseFollowing.filter(start=(1, results[1].created_at),
limit=2)
self.assertEqual(len(results), 2)
self.assertEqual(results[0].to_user_id, 3)
self.assertEqual(results[1].to_user_id, 4)
# test reverse
results = HBaseFollowing.filter(prefix=(1, None),
limit=2,
reverse=True)
self.assertEqual(len(results), 2)
self.assertEqual(results[0].to_user_id, 4)
self.assertEqual(results[1].to_user_id, 3)
results = HBaseFollowing.filter(start=(1, results[1].created_at),
limit=2,
reverse=True)
self.assertEqual(len(results), 2)
self.assertEqual(results[0].to_user_id, 3)
self.assertEqual(results[1].to_user_id, 2)
def test_save_and_get(self):
now = self.ts_now()
following = HBaseFollowing(
from_user_id=123,
created_at=now,
to_user_id=456,
)
following.save()
following = HBaseFollowing.get(from_user_id=123, created_at=now)
self.assertEqual(following.from_user_id, 123)
self.assertEqual(following.created_at, now)
self.assertEqual(following.to_user_id, 456)
following.to_user_id = 789
following.save()
self.assertEqual(following.to_user_id, 789)
following = HBaseFollowing.get(from_user_id=123, created_at=now)
self.assertEqual(following.to_user_id, 789)
# get non-exist object get none
following = HBaseFollowing.get(from_user_id=123,
created_at=self.ts_now())
self.assertIsNone(following)
# wrong row_keys to creat
try:
following = HBaseFollowing(from_user_id=123, to_user_id=456)
following.save()
exception_raised = False
except BadRowKeyException as e:
exception_raised = True
self.assertEqual(str(e), 'created_at not defined')
self.assertEqual(exception_raised, True)
def test_filter(self):
now = self.ts_now()
# dummy friendships
for i in range(1, 5):
HBaseFollowing.create(from_user_id=i,
created_at=now,
to_user_id=999)
for i in range(1, 4):
HBaseFollowing.create(from_user_id=999,
created_at=now + i,
to_user_id=i)
# single instance filter
following = HBaseFollowing.filter(start=(1, now), stop=(1, now))
self.assertEqual(len(following), 1)
self.assertEqual(following[0].from_user_id, 1)
self.assertEqual(following[0].to_user_id, 999)
self.assertEqual(following[0].created_at, now)
# start from non-exist id
following = HBaseFollowing.filter(start=(0, now))
self.assertEqual(len(following), 7)
# range query
followings = HBaseFollowing.filter(start=(1, now))
self.assertEqual(len(followings), 7)
followings = HBaseFollowing.filter(start=(1, now), limit=2)
self.assertEqual(len(followings), 2)
self.assertEqual(followings[0].from_user_id, 1)
self.assertEqual(followings[0].to_user_id, 999)
self.assertEqual(followings[1].from_user_id, 2)
self.assertEqual(followings[1].to_user_id, 999)
# reverse range query
followings = HBaseFollowing.filter(start=(4, now), reverse=True)
self.assertEqual(len(followings), 4)
followings = HBaseFollowing.filter(start=(4, now),
limit=3,
reverse=True)
self.assertEqual(len(followings), 3)
self.assertEqual(followings[-1].from_user_id, 2)
self.assertEqual(followings[-1].to_user_id, 999)
self.assertEqual(followings[0].from_user_id, 4)
self.assertEqual(followings[0].to_user_id, 999)
# part to row_keys range query
followings = HBaseFollowing.filter(start=(5, None),
limit=3,
reverse=True)
self.assertEqual(len(followings), 3)
self.assertEqual(followings[-1].from_user_id, 2)
self.assertEqual(followings[-1].to_user_id, 999)
self.assertEqual(followings[0].from_user_id, 4)
self.assertEqual(followings[0].to_user_id, 999)
followings = HBaseFollowing.filter(start=(4, None),
limit=3,
reverse=True)
self.assertEqual(len(followings), 3)
# None stays behind all values, In Table: (1, 999), (2, 299), (3, 999), ((4, None)), (4, 999)
self.assertEqual(followings[-1].from_user_id, 1)
self.assertEqual(followings[-1].to_user_id, 999)
self.assertEqual(followings[0].from_user_id, 3)
self.assertEqual(followings[0].to_user_id, 999)
# prefix range query
followings = HBaseFollowing.filter(prefix=(999, None),
limit=4,
reverse=True)
self.assertEqual(len(followings), 3)
self.assertEqual(followings[0].from_user_id, 999)
self.assertEqual(followings[0].to_user_id, 3)
self.assertEqual(followings[1].from_user_id, 999)
self.assertEqual(followings[1].to_user_id, 2)
self.assertEqual(followings[-1].from_user_id, 999)
self.assertEqual(followings[-1].to_user_id, 1)
# extra redundant field
followings = HBaseFollowing.filter(start=(1, now, None))
self.assertEqual(len(followings), 7)
