This template demonstrates how to develop and deploy a simple cron-like service running on AWS Lambda using the traditional Serverless Framework.
This examples defines two functions, cron and secondCron, both of which are triggered by an event of schedule type, which is used for configuring functions to be executed at specific time or in specific intervals. For detailed information about schedule event, please refer to corresponding section of Serverless docs.
When defining schedule events, we need to use rate or cron expression syntax.
rate(value unit)
value - A positive number
unit - The unit of time. ( minute | minutes | hour | hours | day | days )
In below example, we use rate syntax to define schedule event that will trigger our rateHandler function every minute
functions:
rateHandler:
handler: handler.run
events:
- schedule: rate(1 minute)Detailed information about rate expressions is available in official AWS docs.
cron(Minutes Hours Day-of-month Month Day-of-week Year)
All fields are required and time zone is UTC only.
| Field | Values | Wildcards |
|---|---|---|
| Minutes | 0-59 | , - * / |
| Hours | 0-23 | , - * / |
| Day-of-month | 1-31 | , - * ? / L W |
| Month | 1-12 or JAN-DEC | , - * / |
| Day-of-week | 1-7 or SUN-SAT | , - * ? / L # |
| Year | 192199 | , - * / |
In below example, we use cron syntax to define schedule event that will trigger our cronHandler function every second minute every Monday through Friday
functions:
cronHandler:
handler: handler.run
events:
- schedule: cron(0/2 * ? * MON-FRI *)Detailed information about cron expressions in available in official AWS docs.
This example is made to work with the Serverless Framework dashboard, which includes advanced features such as CI/CD, monitoring, metrics, etc.
In order to deploy with dashboard, you need to first login with:
serverless login
and then perform deployment with:
serverless deploy
After running deploy, you should see output similar to:
Deploying aws-node-scheduled-cron-project to stage dev (us-east-1)
✔ Service deployed to stack aws-node-scheduled-cron-project-dev (205s)
functions:
rateHandler: aws-node-scheduled-cron-project-dev-rateHandler (2.9 kB)
cronHandler: aws-node-scheduled-cron-project-dev-cronHandler (2.9 kB)There is no additional step required. Your defined schedules becomes active right away after deployment.
In order to test out your functions locally, you can invoke them with the following command:
serverless invoke local --function rateHandler
After invocation, you should see output similar to:
Your cron function "aws-node-scheduled-cron-dev-rateHandler" ran at Fri Mar 05 2021 15:14:39 GMT+0100 (Central European Standard Time)