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73 lines
2.3 KiB
Python
73 lines
2.3 KiB
Python
import time
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class TokenBucket:
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"""
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注意：对于单个key的操作不是线程安全的
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"""
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def __init__(self, key, capacity, fill_rate, default_capacity, redis_conn):
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"""
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:param capacity: 最大容量
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:param fill_rate: 填充速度/每秒
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:param default_capacity: 初始容量
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:param redis_conn: redis connection
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"""
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self._key = key
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self._capacity = capacity
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self._fill_rate = fill_rate
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self._default_capacity = default_capacity
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self._redis_conn = redis_conn
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self._last_capacity_key = "last_capacity"
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self._last_timestamp_key = "last_timestamp"
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def _init_key(self):
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self._last_capacity = self._default_capacity
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now = time.time()
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self._last_timestamp = now
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return self._default_capacity, now
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@property
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def _last_capacity(self):
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last_capacity = self._redis_conn.hget(self._key, self._last_capacity_key)
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if last_capacity is None:
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return self._init_key()[0]
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else:
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return float(last_capacity)
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@_last_capacity.setter
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def _last_capacity(self, value):
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self._redis_conn.hset(self._key, self._last_capacity_key, value)
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@property
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def _last_timestamp(self):
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return float(self._redis_conn.hget(self._key, self._last_timestamp_key))
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@_last_timestamp.setter
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def _last_timestamp(self, value):
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self._redis_conn.hset(self._key, self._last_timestamp_key, value)
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def _try_to_fill(self, now):
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delta = self._fill_rate * (now - self._last_timestamp)
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return min(self._last_capacity + delta, self._capacity)
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def consume(self, num=1):
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"""
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消耗 num 个 token，返回是否成功
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:param num:
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:return: result: bool, wait_time: float
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"""
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# print("capacity ", self.fill(time.time()))
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if self._last_capacity >= num:
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self._last_capacity -= num
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return True, 0
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else:
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now = time.time()
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cur_num = self._try_to_fill(now)
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if cur_num >= num:
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self._last_capacity = cur_num - num
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self._last_timestamp = now
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return True, 0
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else:
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return False, (num - cur_num) / self._fill_rate
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