How to cancel swoole's scheduled task

With the development of PHP language, its application scenarios are becoming more and more extensive. Among them, swoole is a very powerful PHP extension that provides many high-performance network programming functions. However, sometimes when using swoole, we need to cancel the scheduled tasks that have been set. This article will introduce how to cancel swoole's scheduled tasks and related precautions.

Swoole's scheduled tasks

In swoole, by setting scheduled tasks, we can perform certain operations regularly, such as regularly cleaning temporary files, regularly sending heartbeat packets, etc. wait. The scheduled tasks in swoole are implemented based on the swoole_event_add function. The specific usage is as follows:

swoole_timer_tick(interval_ms, callback_function);

// interval_ms：定时任务时间间隔，单位为毫秒
// callback_function：要执行的函数，可以是任何可执行函数的字符串

For example, in the swoole application, if we need to execute a certain function func every 2 seconds, we can implement it through the following code:

$timer_id = swoole_timer_tick(2000, function () use ($active) {
    func();
});

Here swoole will execute the func() function every 2 seconds until the scheduled task is cancelled.

Cancel scheduled tasks

To cancel scheduled tasks in swoole, you can use the swoole_timer_clear function. The calling method is as follows:

swoole_timer_clear(timer_id);

The timer_id here is the unique number of the timer. You can return it when setting up a scheduled task so that the task can be canceled later. For example:

$timer_id = swoole_timer_tick(2000, function () use ($active) {
    func();
});

// 取消定时任务
swoole_timer_clear($timer_id);

It should be noted that if the timer has been executed, the scheduled task cannot be canceled through the swoole_timer_clear function. Therefore, when defining scheduled tasks, it is recommended to avoid this situation as much as possible.

In addition, if you need to execute a task only once within a certain period of time, you can use the swoole_timer_after function. Its usage is similar to swoole_timer_tick, but it will only perform the task once. When canceling the scheduled task, you can use the swoole_timer_clear function.

Notes

When canceling the swoole scheduled task, you need to pay attention to the following points:

1. Ensure that the unique number of the scheduled task is correct .
2. For a scheduled task that has been executed, the task cannot be canceled through the swoole_timer_clear function.
3. The execution interval of scheduled tasks must be set reasonably to avoid executing tasks too frequently, resulting in service performance degradation.
4. Pay attention to writing a comprehensive exception handling mechanism in each scheduled task to avoid unnecessary errors. When canceling a scheduled task, avoid tasks that are still being executed.

Conclusion

swoole is a very powerful PHP extension that can provide many high-performance network programming functions. When using swoole to process scheduled tasks, you need to pay attention to the unique number of the scheduled task, task execution interval, exception handling, etc. Especially when canceling a scheduled task, you must carefully confirm whether the number and other parameters are correct to avoid the situation where the scheduled task cannot be canceled.

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