# Use EventBridge rules with Image Builder pipelines
<a name="ev-rules-for-pipeline"></a>

Events from a wide range of AWS and partner services are streamed to Amazon EventBridge event buses in near real-time. You can also generate custom events, and send events from your own applications to EventBridge. The event buses use rules to determine where to route event data.

Image Builder pipelines are available as EventBridge rule targets, which means that you can run an Image Builder pipeline based on rules that you create to respond to events on the bus, or on a schedule.

For a summary of system generated events that Image Builder sends to EventBridge, see [Event messages that Image Builder sends](integ-eventbridge.md#integ-eb-event-summary).

**Note**  
Event buses are specific to a Region. The rule and the target must be in the same Region.

**Topics**
+ [EventBridge terms](#ev-terms)
+ [View EventBridge rules for your Image Builder pipeline](#ev-rules-pipeline-tab)
+ [Use EventBridge rules to schedule a pipeline build](#ev-rules-schedule-pipeline)

## EventBridge terms
<a name="ev-terms"></a>

This section contains a summary of terms to help you understand how EventBridge integrates with your Image Builder pipelines.

Event  
Describes a change in an environment that might affect one or more application resources. The environment can be an AWS environment, a SaaS partner service or application, or one of your applications or services. You can also set up scheduled events on a timeline.

Event bus  
A pipeline that receives event data from applications and services.

Source  
The service or application that sent the event to the event bus.

Target  
A resource or endpoint that EventBridge invokes when it matches a rule, delivering data from the event to the target.

Rule  
A rule matches incoming events and sends them to targets for processing. A single rule can send an event to multiple targets, which can then run in parallel. Rules are based either on an event pattern or a schedule.

Pattern  
An event pattern defines the event structure and the fields that a rule matches in order to initiate the target action.

Schedule  
Schedule rules perform an action on a schedule, such as running an Image Builder pipeline to refresh an image on a quarterly basis. There are two types of schedule expressions:   
+ **Cron expressions** – Match specific scheduling criteria using the cron syntax that can outline simple criteria; for example, running weekly on a specific day. You can also establish more complex criteria, such as running quarterly on the fifth day of the month, between 2 AM and 4 AM.
+ **Rate expressions** – Specify a regular interval when the target is invoked, such as every 12 hours.

## View EventBridge rules for your Image Builder pipeline
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The **EventBridge rules** tab in the Image Builder **Image pipelines** detail page displays EventBridge event buses that your account has access to, and the rules for the selected event bus that apply to the current pipeline. This tab also links directly to the EventBridge console for creating new resources.

**Actions that link to the EventBridge console**
+ **Create event bus**
+ **Create rule**

To learn more about EventBridge, see the following topics in the *Amazon EventBridge User Guide*.
+ [What is Amazon EventBridge](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-what-is.html)
+ [Amazon EventBridge event buses](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-event-bus.html)
+ [Amazon EventBridge events](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-events.html)
+ [Amazon EventBridge rules](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-rules.html)

## Use EventBridge rules to schedule a pipeline build
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For this example, we create a new schedule rule for the default event bus, using a rate expression. The rule in this example generates an event on the event bus every 90 days. The event initiates a pipeline build to refresh the image.

1. Open the EC2 Image Builder console at [https://console.aws.amazon.com/imagebuilder/](https://console.aws.amazon.com/imagebuilder/).

1. To see a list of the image pipelines created under your account, choose **Image pipelines** from the navigation pane.
**Note**  
The list of image pipelines includes an indicator for the type of output image that is created by the pipeline – AMI or Docker.

1. To view details or edit a pipeline, choose the **Pipeline name** link. This opens the detail view for the pipeline.
**Note**  
You can also select the check box next to the **Pipeline name**, then choose **View detail**.

1. Open the **EventBridge rules** tab.

1. Keep the default event bus that is pre-selected in the **Event Bus** panel.

1. Choose **Create rule**. This takes you to the **Create rule** page in the Amazon EventBridge console.

1. Enter a name and description for the rule. The rule name must be unique within the event bus for the selected Region.

1. In the **Define pattern** panel, choose the **Schedule** option. This expands the panel, with the **Fixed rate every** option selected.

1. Enter `90` in the first box, and select **Days** from the drop-down list.

1. Perform the following actions in the **Select targets** panel:

   1. Select `EC2 Image Builder` from the **Target** drop-down list.

   1. To apply the rule to an Image Builder pipeline, select the target pipeline from the **Image Pipeline** drop-down list.

   1. EventBridge needs permission to initiate a build for the selected pipeline. For this example, keep the default option to **Create a new role for this specific resource**.

   1. Choose **Add target**.

1. Choose **Create**

**Note**  
To learn more about settings for rate expression rules that are not covered in this example, see [Rate expressions](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-create-rule-schedule.html#eb-rate-expressions) in the *Amazon EventBridge User Guide*.