January 30, 2023
aws eventbridge archive feature custom event bus data loss mitigation event replay cloudformation typescript code examples event listing
WS EventBridge is a fully managed event bus that makes it easy to process, store and analyze events generated by cloud resources, applications and custom sources. One of the powerful features of EventBridge is the ability to archive events, which allows you to store event data for later analysis and replay.
In this section, we'll take a closer look at how you can take advantage of the archive feature in EventBridge to save you in situations like mitigating data loss in case of failed events and the ability to replay them later.
We'll focus on the first 2 points for this article.
One of the most significant benefits of archiving EventBridge events is that it helps you to mitigate data loss in case of failed events. When an event is sent to a custom event bus in EventBridge, it is processed by the target. If the target fails to process the event, the event is not lost and can be replayed later.
To illustrate this, let's consider a scenario where you have a custom event bus in EventBridge and you are sending events to a Lambda function as the target. The Lambda function is responsible for processing the events and storing the data in a database. If the Lambda function fails to process the event, the event will be lost, and the data will not be stored in the database.
However, by archiving the events, you can ensure that the events are not lost and can be replayed later. In this way, you can mitigate the risk of data loss and ensure that your data is always up-to-date.
Another benefit of archiving EventBridge events is that you can replay the events later. This is useful when you need to reprocess the events or when you need to perform an analysis on the data.
For example, let's consider a scenario where you have a custom event bus in EventBridge and you are sending events to a Lambda function as the target. The Lambda function is responsible for processing the events and storing the data in a database. If you need to perform an analysis on the data, you can replay the events and process them again.
First we need to create a Custom EventBridge Event Bus. In CloudFormation, you can create a custom event bus by defining a resource of type `AWS::Events::EventBus`.
Resources:
EventBus:
Type: AWS::Events::EventBus
Properties:
Name: custom-event-bus
EventBusPolicy:
Version: '2012-10-17'
Statement:
- Effect: Allow
Principal: '*'
Action: events:PutEvents
Resource: !GetAtt EventBus.Arn
Then to enable archiving for your custom event bus, you need to create the archive for this bus
EventBusArchive:
Type: AWS::Events::Archive
Properties:
Description: Archive for custom-event-bus
EventBusName: custom-event-bus
RetentionDays: 7
Finally we create an event pattern for this event bus
EventPattern:
Type: AWS::Events::EventPattern
Properties:
EventPattern:
source:
- custom-event-bus
Now you can simply send events to your event bus, and they'll automatically get archived. See the example below for sending and retrieving events from archive. (also possible via AWS console):
import { EventBridge, CloudFormation } from 'aws-sdk';
const eventBridge = new EventBridge();
const cloudFormation = new CloudFormation();
const archiveEvents = async (eventBusName: string, events: EventBridge.Types.PutEventsRequestEntry[]) => {
try {
const result = await eventBridge.putEvents({
Entries: events,
EventBusName: eventBusName
}).promise();
console.log(`Successfully archived events: ${JSON.stringify(result)}`);
} catch (error) {
console.error(`Error archiving events: ${error}`);
}
};
const getArchivedEvents = async (eventBusName: string, eventSourceArn: string) => {
try {
const result = await eventBridge.listArchivedRules({
EventBusName: eventBusName,
EventSourceArn: eventSourceArn
}).promise();
console.log(`Successfully retrieved archived events: ${JSON.stringify(result)}`);
} catch (error) {
console.error(`Error retrieving archived events: ${error}`);
}
};
export { archiveEvents, getArchivedEvents };
And you can make use of the SDK events.replayEvents
function to replay them (also possible via AWS console):
const AWS = require('aws-sdk');
const events = new AWS.EventBridge({apiVersion: '2015-10-07'});
const replayArchivedEvents = async () => {
const result = await events.replayEvents({
EventBusName: 'custom-event-bus',
EventSourceArn: 'arn:aws:events:eu-west-1:xxxxxxxxx:event-bus/custom-event-bus',
ReplayName: 'replay-events-1',
RuleArns: [
'arn:aws:events:eu-west-1:xxxxxxxxx:rule/example-rule',
],
}).promise();
console.log(result);
};
replayArchivedEvents();
That's all for this one. Thanks for reading Devspedia. I love you and I'll see you the next time! :)
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