用python 批量操作redis数据库

import redis

r = redis.Redis(host='127.0.0.1', port=6379, password='1234567890')
with r.pipeline() as ctx:
  a = time.time()
  ctx.hset('current', "time2", a)
  ctx.hset('current', "time3", a)
  res = ctx.execute()
  print("result: ", res)

# -*- coding:utf-8 -*-

import redis
from redis import WatchError
from concurrent.futures import ProcessPoolExecutor

r = redis.Redis(host='127.0.0.1', port=6379)

# 减库存函数, 循环直到减库存完成
# 库存充足, 减库存成功, 返回True
# 库存不足, 减库存失败, 返回False
def decr_stock():
  # python中redis事务是通过pipeline的封装实现的
  with r.pipeline() as pipe:
    while True:
      try:
        # watch库存键, multi后如果该key被其他客户端改变, 事务操作会抛出WatchError异常
        pipe.watch('stock:count')
        count = int(pipe.get('stock:count'))
        if count > 0: # 有库存
          # 事务开始
          pipe.multi() # multi 判断 watch 监控的 key 是否被其他客户端改变
          pipe.decr('stock:count')
          # 把命令推送过去
          # execute返回命令执行结果列表, 这里只有一个decr返回当前值
          result = pipe.execute()[0]
          print("result: ", result)
          return True
        else:
          return False
      except WatchError as e:
        # 打印WatchError异常, 观察被watch锁住的情况
        print(e.args)
      finally:
        pipe.unwatch()


def worker():
  while True:
    # 没有库存就退出
    if not decr_stock():
      break


# 实验开始
# 设置库存为100
r.set("stock:count", 100)

# 多进程模拟多个客户端提交
with ProcessPoolExecutor(max_workers=2) as pool:
  for _ in range(10):
    pool.submit(worker)

import redis
import time

  r = redis.Redis(host='127.0.0.1', port=31320, password='12345678')
  
  lua = """
  local key = KEYS[1]
  local field = ARGV[1]
  local timestamp_new = ARGV[2]
  
  -- get timestamp of the key in redis
  local timestamp_old = redis.call('hget', key, field)
  -- if timestamp_old == nil, it means the key is not exist
  if timestamp_old == nil or timestamp_old == false or timestamp_new > timestamp_old then
    redis.call('hset', key, field .. 1, timestamp_new)
    -- timestamp_new > timestamp_old
    return redis.pcall('hset', key, field, timestamp_new)
  end
  
  """

  cmd = r.register_script(lua)

  cur_time = time.time()
  cmd(keys=['current'], args=["time", cur_time])

import redis
import time

  r = redis.Redis(host='127.0.0.1', port=31320, password='12345678')
  
  lua = """
  local key = KEYS[1]
  local field = ARGV[1]
  local timestamp_new = ARGV[2]
  
  -- get timestamp of the key in redis
  local timestamp_old = redis.call('hget', key, field)
  -- if timestamp_old == nil, it means the key is not exist
  if timestamp_old == nil or timestamp_old == false or timestamp_new > timestamp_old then
    redis.call('hset', key, field .. 1, timestamp_new)
    -- timestamp_new > timestamp_old
    return redis.pcall('hset', key, field, timestamp_new)
  end
  
  """
  sha = r.script_load(lua)
  print(r.evalsha(sha, 1, 'current', 'time', time.time()))