Cron tasks on AWS Lambda

A Lambda function can be invoked on a schedule using the schedule event. This is useful for running cron tasks, such as sending emails or cleaning up data. For example:

serverless.yml


functions:
    cron:
        # ...
        events:
            # the schedule can be defined as a rate
            - schedule: rate(1 hour)
            # or as a cron expression
            - schedule: cron(0 12 * * ? *)

CLI commands

Cron events can be used to run CLI commands with the Console runtime.

In that case, use the php-xx-console runtime (for example php-84-console).

This is usually best when coupled with a framework like Laravel or Symfony, or when porting an existing cron task to AWS Lambda.

Laravel

serverless.yml


functions:
    # ...
    cron:
        handler: artisan
        runtime: php-84-console
        events:
            - schedule:
                rate: rate(1 hour)
                # The command needs to be passed as a JSON string
                # (that is why it's quoted twice: '"..."')
                input: '"my-command --option=value"'

The configuration above will run php artisan my-command --option=value every hour in the Lambda function named “cron”.

Note that Laravel already provides a scheduler that can be used instead of the schedule event. If you want to use it instead, run the artisan schedule:run command every minute:

serverless.yml


functions:
    # ...
    artisan:
        handler: artisan
        runtime: php-84-console
        events:
            - schedule:
                rate: rate(1 minute)
                input: '"schedule:run"'

Symfony

serverless.yml


functions:
    # ...
    cron:
        handler: bin/console
        runtime: php-84-console
        events:
            - schedule:
                rate: rate(1 hour)
                # The command needs to be passed as a JSON string
                # (that is why it's quoted twice: '"..."')
                input: '"my-command --option=value"'

The configuration above will run bin/console my-command --option=value every hour in the Lambda function named “cron”.

PHP

serverless.yml


functions:
    # ...
    cron:
        handler: my-script.php
        runtime: php-84-console
        events:
            - schedule:
                rate: rate(1 hour)

The configuration above will run php my-script.php every hour in the Lambda function named “cron”.

If you need to pass CLI options to the script, use the input option:

serverless.yml


functions:
    # ...
    cron:
        handler: my-script.php
        runtime: php-84-console
        events:
            - schedule:
                rate: rate(1 hour)
                # The command needs to be passed as a JSON string
                # (that is why it's quoted twice: '"..."')
                input: '"my-command --option=value"'

The configuration above will run php my-script.php my-command --option=value every hour in the Lambda function named “cron”.

Read more about the options for the schedule event in the Serverless documentation .

Cron functions

On top of running CLI cron tasks with the php-xx-console runtime, we can also run event-driven functions (using the PHP function runtime) as cron tasks.

Laravel

serverless.yml


functions:
    # ...
    cron:
        handler: App\MyCronHandler
        runtime: php-84
        events:
            - schedule:
                rate: rate(1 hour)

The handler can be a class implementing the Handler interface:


namespace App;
 
use Bref\Context\Context;
 
class MyCronHandler implements \Bref\Event\Handler
{
    public function handle($event, Context $context): void
    {
        echo 'Hello ' . $event['name'] ?? 'world';
    }
}

The configuration above will run MyCronHandler::handle() every hour.

It is possible to provide data inside the $event variable via the input option:

serverless.yml


functions:
    cron:
        events:
            - schedule:
                rate: rate(1 hour)
                input:
                    foo: bar
                    hello: world

Symfony

serverless.yml


functions:
    # ...
    cron:
        handler: App\MyCronHandler
        runtime: php-84
        events:
            - schedule:
                rate: rate(1 hour)

The handler can be a class implementing the Handler interface:


namespace App;
 
use Bref\Context\Context;
 
class MyCronHandler implements \Bref\Event\Handler
{
    public function handle($event, Context $context): void
    {
        echo 'Hello ' . $event['name'] ?? 'world';
    }
}

The configuration above will run MyCronHandler::handle() every hour.

It is possible to provide data inside the $event variable via the input option:

serverless.yml


functions:
    cron:
        events:
            - schedule:
                rate: rate(1 hour)
                input:
                    foo: bar
                    hello: world

PHP

serverless.yml


functions:
    # ...
    cron:
        handler: function.php
        runtime: php-84-console
        events:
            - schedule:
                rate: rate(1 hour)

The example above will run the function returned by function.php every hour in AWS Lambda. For example:


<?php
require __DIR__ . '/vendor/autoload.php';
 
return function ($event) {
    echo 'My cron function is running!';
};

It is possible to provide data inside the $event variable via the input option:

serverless.yml


functions:
    cron:
        events:
            - schedule:
                rate: rate(1 hour)
                input:
                    foo: bar
                    hello: world

Read more about the options for the schedule event in the Serverless documentation .