Cron Jobs

SST can help you schedule Lambda functions to run at specified time intervals. To do this you can use the Cron construct.

Follow this tutorial on creating a simple serverless cron job in SST.

There are two ways to specify the schedule in the construct.

Rate expressions

You can specify a rate at which a function runs. For example, every 5 minutes.

import { Cron } from "@serverless-stack/resources";

new Cron(stack, "Cron", {
  schedule: "rate(5 minutes)",
  job: "src/lambda.main",
});

The fastest rate a cron job can be run is every minute.

Here are some sample rate expressions:

If the value is equal to 1, then the unit must be singular. If the value is greater than 1, the unit must be plural.

Alternatively, you can specify a cron expression to have a function run at specific times, ie. every day at 12:00pm.

import { Cron } from "@serverless-stack/resources";

new Cron(stack, "Cron", {
  schedule: "cron(0 12 * * ? *)",
  job: "src/lambda.main",
});

All cron expressions use the UTC+0 time zone.

Here are some example cron expressions:

Minutes	Hours	Day of month	Month	Day of week	Year	Description
0	10	*	*	?	*	Run at 10:00 am every day
15	12	*	*	?	*	Run at 12:15 pm every day
0	18	?	*	MON-FRI	*	Run at 6:00 pm every Monday through Friday
0	8	1	*	?	*	Run at 8:00 am every 1st day of the month
0/15	*	*	*	?	*	Run every 15 minutes
0/10	*	?	*	MON-FRI	*	Run every 10 minutes Monday through Friday
0/5	8-17	?	*	MON-FRI	*	Run every 5 minutes Monday through Friday between 8:00 am and 5:55 pm
0/30	20-2	?	*	MON-FRI	*	Run every 30 minutes Monday through Friday between 10:00 pm on the starting day to 2:00 am on the following day