AWS Lambda 计划任务 [英] AWS Lambda Scheduled Tasks

问题描述

亚马逊发布了 AWS Lambda(

将预定事件添加到现有的 lambda

导航到 lambda 的触发器"选项卡，选择添加触发器"，然后指定CloudWatch 事件 - 计划"触发器.我有一个带有 SNS 触发器的现有 lambda 的示例屏幕截图:

加载后，用于配置此触发器的 UI 与上面将计划事件添加到新 lambda"部分中的屏幕截图相同.

讨论

对于您的示例，您需要使用 cron() 而不是 rate().lambda 中的 Cron 表达式需要所有字段，并以 UTC 表示.因此，要每天在下午 5 点 (UTC) 运行一个函数，请使用以下 cron 表达式:

cron(0 17 * * ? *)

更多资源

• AWS 文档 - 使用调度表达式评分或 Cron
• AWS 文档 - 使用 AWS 按计划运行 AWS Lambda 函数命令行
• AWS 文档 - 教程:将 AWS Lambda 与 Scheduled 结合使用活动
  • AWS 提供了一个示例蓝图"，它使用名为 lambda-canary 的 cron 表达式，可以在从 AWS 控制台创建函数期间选择该表达式.
  • 本教程将引导您完成此蓝图的配置.

注意事项

• 自此功能首次发布以来，此事件类型的名称已从计划事件"更改为CloudWatch 事件 - 计划".
• 在此功能发布之前，此问题的推荐解决方案(根据 "AWS Lambda 入门" 在 42 分 50 秒) 是使用 SWF创建计时器，或使用外部应用程序创建计时器.
• 自从预定的活动博客文章发布以来，Lambda 用户界面已经过大修，其中的屏幕截图不再准确.有关最新修订，请参阅我在 2017 年 3 月 10 日更新的屏幕截图.

Amazon announced AWS Lambda (http://aws.amazon.com/lambda/).

The product description includes:

Scheduled Tasks

AWS Lambda functions can be triggered by external event timers, so functions can be run during regularly scheduled maintenance times or non-peak hours. For example, you can trigger an AWS Lambda function to perform nightly archive cleanups during non-busy hours.

When I read this, I understood I could finally have a way to consistently do "cron-like" tasks. I want to run a specific query everyday at 5PM let's say.

However I do not find this anywhere in the documentation. They only mention triggers on programatical events, or events from other AWS services.

Did I misunderstand? Or can someone point me to the documentation?

解决方案

Native Support for Scheduled Events added October 8, 2015:

As announced in this AWS blog post, scheduling is now supported as an event source type (also called triggers) called "CloudWatch Events - Schedule", and can be expressed as a rate or a cron expression.

Add Scheduled Event to a new lambda

Navigate to the 'Configure triggers' step of creation, and specify the 'CloudWatch Event - Schedule' trigger. Example configuration below:

Add Scheduled Event to an existing lambda

Navigate to the 'Triggers' tab of your lambda, select 'Add Trigger', and specify the 'CloudWatch Event - Schedule' trigger. Example screenshot where I have an existing lambda with an SNS trigger:

Once loaded, the UI to configure this trigger is identical to the screenshot in the above "Add Scheduled Event to a new lambda" section above.

Discussion

For your example case, you'll want to use cron() instead of rate(). Cron expressions in lambda require all fields and are expressed in UTC. So to run a function every day at 5pm (UTC), use the following cron expression:

cron(0 17 * * ? *)

Further Resources

• AWS Documentation - Schedule Expressions Using Rate or Cron
• AWS Documentation - Run an AWS Lambda Function on a Schedule Using the AWS CLI
• AWS Documentation - Tutorial: Using AWS Lambda with Scheduled Events
  • AWS has provided a sample "blueprint" that uses a cron expression called lambda-canary that can be selected during function creation from the AWS console.
  • This tutorial walks you through configuration of this blueprint.

Notes

• The name of this event type has changed from "Scheduled Event" to "CloudWatch Events - Schedule" since this feature was first released.
• Prior to the release of this feature, the recommended solution to this issue (per "Getting Started with AWS Lambda" at 42min 50secs) was to use SWF to create a timer, or to create a timer with an external application.
• The Lambda UI has been overhauled since the scheduled event blog post came out, and the screenshots within are no longer exact. See my updated screenshots above from 3/10/2017 for latest revisions.

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