Announcing the General Availability of the Amazon EventBridge Scheduler L2 Construct
April 7, 2025Today we’re announcing the general availability (GA) of the Amazon EventBridge Scheduler and Targets Level 2 (L2) constructs in the AWS Cloud Development Kit (AWS CDK) construct library. EventBridge Scheduler is a serverless scheduler that enables users to schedule tasks and events at scale. Prior to the launch of these L2 constructs, developers had to define all relevant properties (via L1 constructs) across schedules and provide the glue logic between resources when defining their AWS CDK applications. The graduated constructs make it easier for users to configure EventBridge schedules, groups, and targets for AWS service integrations. They follow the AWS CDK L2 higher-level API design simplifications and provide a backwards-compatible guarantee across minor versions. Developers can use those alongside other existing stable AWS CDK constructs ready for production use.
Background
The AWS Cloud Development Kit (CDK) is an open-source software development framework for defining cloud infrastructure in code and provisioning it through AWS CloudFormation. It contains pre-written modular and reusable cloud components known as constructs. Constructs are the basic building blocks representing one or more AWS CloudFormation resources and their configuration. They are available in different abstraction levels. L1 constructs are the lowest-level constructs which map directly to AWS CloudFormation resources without abstractions. L2 constructs are thoughtfully developed and provide a higher-level abstraction through an intuitive intent-based API. They leverage default property configurations, best practice security policies, and convenience methods that make it simpler and quicker to define and deploy resources.
Amazon EventBridge Scheduler is a serverless scheduler that allows users to create, run, and manage tasks from one central, managed service. With EventBridge Scheduler, users can create schedules using cron and rate expressions for recurring patterns, or configure one-time invocations. EventBridge supports templated and universal targets. Templated targets include common API operations across a group of core AWS services, such as publishing a message to an Amazon Simple Notification Service (Amazon SNS) topic or invoking an AWS Lambda function. Universal targets are customized triggers supporting more than 270 AWS services and over 6,000 API operations on a schedule. Users can use schedule groups to organize their schedules.
With the L2 constructs for Amazon EventBridge Scheduler and Targets, it becomes even simpler for users to configure and integrate those resources into their CDK applications. Let’s explore the benefits by looking at some examples.
Using the L2 EventBridge Scheduler construct
We introduce two use cases for the EventBridge Scheduler and Targets L2 constructs to demonstrate their usage within common scenarios. Each example is equipped with sample code, emphasizing the simplifications achieved by the L2 constructs.
Example 1 – One time reminder through Amazon SNS
In the first use case, users want to configure one-time notifications to receive reminders of their favorite conferences at a specific time, for example a user may want to set a reminder one month before the start of AWS re:Invent to be reminded of their participation.
The example below uses the EventBridge Scheduler construct with a templated Amazon SNS target. The target applies an on-time schedule configuration and is configured with an Amazon Simple Queue Service (Amazon SQS) dead-letter queue to capture and retry failed events. The schedule payload is encrypted using a customer-managed AWS Key Management Service (AWS KMS) key.
const snsTarget = new targets.SnsPublish(topic, { input: ScheduleTargetInput.fromObject({ message: "Reminder: AWS re:Invent starts in one month.", }), deadLetterQueue: deadLetterQueue,
}); const schedule = new Schedule(this, "ReminderSchedule", { description: "This schedule publishes a one-time notification to an Amazon SNS topic.", schedule: ScheduleExpression.at( new Date(2025, 10, 1), // Nov 01, 2025 cdk.TimeZone.AMERICA_LOS_ANGELES ), target: snsTarget, key: key,
});
From the code example, we can see that well-defined interfaces for ScheduleTargetInput, and ScheduleExpression make it easy to select matching configuration values.
The SnsPublish target and Schedule constructs seamlessly integrate with the existing L2 constructs for Amazon SNS, Amazon SQS, and Amazon KMS. They abstract away the gluing logic used to configure the target API operation, dead-letter queue, and encryption settings with correct references. Instead of manually crafting permissions, the construct generates an AWS Identity and Access Management (IAM) execution role with the minimum necessary permissions to interact with the templated target, as shown in the policy below.
{ "Version": "2012-10-17", "Statement": [ { "Action": "sns:Publish", "Resource": "arn:aws:sns:us-east-1:123456789012:<TOPIC_NAME>", "Effect": "Allow" }, { "Action": "kms:Decrypt", "Resource": "arn:aws:kms:us-east-1:123456789012:key/<UUID>", "Effect": "Allow" }, { "Action": "sqs:SendMessage", "Resource": "arn:aws:sqs:us-east-1:123456789012:<QUEUE_NAME>", "Effect": "Allow" } ] }The construct sets default properties. For example, it applies default configurations for the retry policy if not explicitly stated. As shown in Figure 1, the above defined schedule has been defined with a 1-day maximum event retention time and 185 maximum retries.
Example 2 – Start / Stop EC2 instance during business hours
In the second scenario, a recurring cron schedule is used to automatically stop Amazon EC2 instances during the business hours of a specific time zone.
The example below uses the EventBridge Scheduler construct with a universal target to perform the Amazon EC2 stopInstance API operation. It creates a custom schedule group to organize the schedules by time zone and allows an Amazon Lambda function to read all schedules in it for administrative purposes.
const group = new ScheduleGroup(this, "ScheduleGroup", { scheduleGroupName: "Europe-London",
}); new Schedule(this, "Schedule", { schedule: ScheduleExpression.cron({
minute: "0",
hour: "23",
timeZone: cdk.TimeZone.EUROPE_LONDON, }), target: new targets.Universal({
service: "ec2",
action: "stopInstances",
input: ScheduleTargetInput.fromObject({ InstanceIds: [ec2Instance.instanceId],
}), }), scheduleGroup: group,
}); group.grantReadSchedules(lambdaFunction);
Similar to the first example, the ScheduleExpression and ScheduleTargetInput help users to define the correct input types. The universal target is one of the options allowed by the scheduler-target constructs that allow users to perform SDK API operations on AWS services such as Amazon EC2.
The ScheduleGroup construct is used to create the group, which is used as a property on the Schedule construct. The group implements convenience methods that allow simplified permissions management. The example above grants read permissions for the schedule group to an Amazon Lambda function, which is applied to the resources without additional configuration.
Community Shout-Outs
The CDK team would like to give a huge shout-out to the awesome members of the community that contributed to this construct to help get it where it is today! Thank you to:
Conclusion
In this post, we introduced the general availability of the AWS CDK L2 construct for Amazon EventBridge Scheduler and Targets. We showcased practical implementations of the new construct, leveraging two example use cases. For more details on the EventBridge Scheduler L2 construct and examples of its use, see the Scheduler CDK Documentation.
If you’re new to AWS CDK and want to get started, we highly recommend checking out the CDK documentation and the CDK workshop.
