如何安排 lambda function 在另一个 lambda function 记录特定条目后运行 2 小时？

Question

I want to run a lambda function 2 hours after another lambda function logs an entry like so console.log ('ScheduleSecondFunction');

Is there a way to do that using CloudWatch?

Answer 1

I think steps to your goal could involve CloudWatch (CW) custom metric filter to detect ScheduleSecondFunction entry in your CW Logs. The metric would be used to define a CW Alarm . When the alarm triggers it send a SNS notification to a lambda function . The function would parse the alarm event and and start a Step Function with Wait state. The state would wait 2 hours and then invoke your final lambda function.

There are some alternatives to the above. Instead of using SNS and the second, intermediate lambda function, you could use CW Events rule to detect alarm change and trigger Step Function directly from the CW Events. This could reduce the complexity of using SNS and intermediate lambda function.

Yet another possibility, could be setting up the CW Alarm with a period of 2 hours. However, I'm not sure how using 2 hour period in CW Alarm would behave in your scenario. But if this would work, then you could eliminate the Step Function, as you could trigger your final lambda function directly from the CW Alarms. But its something that could be tested and verified.