python自定义装饰器，实现轮询监控数据库，并且根据字段内容变更打印相应日志或结束循环

使用方法

可以写个while True的循环监控数据，再分别定义每个状态要做什么事情

注意:

1. 循环中不要写breake
2. 不要return, 换成yield, 把函数作为一个生成器，由装饰器控制循环

代码示例

import functools
import time
 
from utils.log_setting import logger
from config import settings
 
 
def monitorDB(field_name, continue_values=[], stop_values=[]):
    '''
    监听函数返回值，与stop_flags相等时结束监听
    field_name: 字段名，只用于打印
    continue_values: 非列表中的返回值跳出循环
    stop_value: 与被装饰函数返回值相等时跳出循环结束监听
    '''
 
    def decorator(func):
        # 使用装饰器语法，将装饰器应用到函数上
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            previous_value = None
            retry_wait_time = settings.MONITORDB.CONFIG.RETRY_WAIT_TIME  # 重试等待时间
            retry_count = settings.MONITORDB.CONFIG.RETRY_COUNT  # 最大重试次数
            run_count = 1  # 运行次数
            time_sleep_list = list(range(retry_wait_time, retry_wait_time * (retry_count + 1), retry_wait_time))
            time_start = time.perf_counter()
            try:
                time.sleep(0.5)
                # 获取最新的字段值
                time.sleep(1)
                current_value = next(func(*args, **kwargs))
            except StopIteration:
                logger.warning(f"{func.__name__}, 返回数据为空")
            while True:
                time.sleep(0.2)
                # 判断装饰器参数完整性
                if stop_values is [] and continue_values is []:
                    logger.error("{func.__name__}, 装饰器参数缺失")
                    break
                # 判断是否是列表中的返回值
                elif continue_values is not [] and current_value not in continue_values:
                    # 判断第一次执行
                    if previous_value is not None:
                        logger.info(f"{func.__name__}, {field_name} 从 {previous_value} 变为 {current_value}, done")
                    else:
                        logger.info(f"{func.__name__}, {field_name}: {current_value}")
                    break
                # 判断停止循环
                elif stop_values is not [] and current_value in stop_values:
                    # 判断第一次执行
                    if previous_value is not None:
                        logger.info(f"{func.__name__}, {field_name} 从 {previous_value} 变为 {current_value}, done")
                    else:
                        logger.info(f"{func.__name__}, {field_name}: {current_value}")
                    break
                elif current_value != previous_value:
                    time_start = time.perf_counter()
                    # 判断第一次执行
                    if previous_value is not None:
                        logger.info(f"{func.__name__}, {field_name} 从 {previous_value} 变为 {current_value}")
                    previous_value = current_value
                    retry_wait_time = settings.MONITORDB.CONFIG.RETRY_WAIT_TIME  # 重试等待时间
                    run_count = 1  # 运行次数
                    time_sleep_list = list(range(0, retry_wait_time * (retry_count + 1), retry_wait_time))
                elif current_value == previous_value:
                    time_run = time.perf_counter() - time_start
                    time_run_fmt = '{:.2f}s'.format(time_run)
                    print(
                        '\r***************************************************************************等待中{:.2f}s***************************************************************************'.format(time_run),
                        end="",
                    )
                    if time_run > retry_wait_time:
                        print('')
                        try:
                            logger.info(f"已等待{time_run_fmt}秒, {field_name}: {current_value}, 第{run_count}次重试...")
                            current_value = next(func(*args, **kwargs))
                            run_count += 1
                            retry_wait_time = time_sleep_list.pop(1)
                        except IndexError:
                            logger.warning(f"已等待{time_run_fmt}秒, {field_name}: {current_value}, 第{run_count}次重试失败, 不再重试")
                            break
                else:
                    logger.warning(f"{func.__name__}, 预料之外的参数field_name: {field_name}, continue_values: {continue_values}, stop_values: {stop_values}, current_value: {current_value}, previous_value: {previous_value}")
                time.sleep(0.2)
 
        return wrapper
 
    return decorator
 
 
if __name__ == '__main__':
 
    @monitorDB('IftttRuleTaskDetail_state', continue_values=[1, 2, 3, 4], stop_values=[4])
    def check_field_value():  # 模拟获取字段的当前值，可以替换为实际的代码
        while True:
            current_value = 0
            time.sleep(1)
            logger.info("程序运行中...")
            current_value = int(input('输入: '))
            yield current_value
 
    check_field_value()