# Send messages via EventBridge Pipes
This project is the CDK implementation of ['Send Message via Pipes'](https://github.com/aws-samples/aws-refactoring-to-serverless/blob/main/patterns/send-message-via-pipes.md) serverless refactoring using Node and TypeScript. It shows how you can reduce your application code and improve consistency by utilizing EventBridge Pipes.


## How it works
This sample application persists an order object in a DynamoDB table and also sends an order message as an event for other components to be notified.

The code deploys two versions of this application:
- process-order-original: The lambda code saves an item into a DynamoDB table and separately sends an event message to an event bus.
- process-order-refactored: The order event is published automatically via DynamoDB Streams and EventBridge Pipes. The code to send the message is removed from the Lambda function. 

---
## Deploy the applications

To build this app, navigate to `implementation/send-message-via-pipes` folder. Then run the following:

```bash
npm install -g aws-cdk
npm install
npm run build
```

This will install the necessary CDK, dependencies, build your TypeScript files and CloudFormation template.

Next, deploy the 2 Stacks to your AWS Account.
``` 
cdk deploy --all
```

## Testing

- Before testing the applications, add EventBridge rules to the bus to send events to CloudWatch for  review (replace `<account-id>` with your 12-digit account ID number):

```
# Original stack

# Create a CloudWatch Log group
aws logs create-log-group --log-group-name /aws/events/eventbridge-logs-original
# Create a rule
aws events put-rule --name eventbridge-logs --event-pattern "{\"account\":[\"<account-id>\"]}" --event-bus-name OrdersEventBusOriginal
# Configure the rule to send to CloudWatch
aws events put-targets --rule eventbridge-logs --targets "Id"="1","Arn"="arn:aws:logs:us-east-1:<account-id>:log-group:/aws/events/eventbridge-logs-original" --event-bus-name OrdersEventBusOriginal

# Same for the refactored stack

aws logs create-log-group --log-group-name /aws/events/eventbridge-logs-refactored
aws events put-rule --name eventbridge-logs --event-pattern "{\"account\":[\"<account-id>\"]}" --event-bus-name OrdersEventBusRefactored
aws events put-targets --rule eventbridge-logs --targets "Id"="1","Arn"="arn:aws:logs:us-east-1:<account-id>:log-group:/aws/events/eventbridge-logs-refactored" --event-bus-name OrdersEventBusRefactored

```  

- Now, let's invoke the original lambda function that sends a message from the code:
``` 
aws lambda invoke \
    --function-name ProcessOrderOriginal \
    --invocation-type Event \
    --payload '{ "orderId": "1", "items": [ "A", "B", "C" ] }' \
    --cli-binary-format raw-in-base64-out \
    response.json

```
You should see StatusCode:202

- Next, let's invoke the refactored lambda function
 ``` 
aws lambda invoke \
    --function-name ProcessOrderRefactored \
    --invocation-type Event \
    --payload '{ "orderId": "1", "items": [ "A", "B", "C" ] }' \
    --cli-binary-format raw-in-base64-out \
    response.json
``` 

You should see StatusCode:202     

## Verify

Login to your AWS console and navigate to Amazon CloudWatch. You should see 2 log groups:

- /aws/events/eventbridge-logs-original
- /aws/events/eventbridge-logs-refactored

Each log group should have a log stream displaying a message that event bus received, similar to the following:
```
{
    "version": "0",
    "id": "8db2791e-eab2-efd5-18aa-cf6ca95a3894",
    "detail-type": "order-details",
    "source": "my-source",
    "account": "<redacted>",
    "time": "2023-03-01T19:11:30Z",
    "region": "us-east-1",
    "resources": [],
    "detail": {
        "orderId": "1",
        "items": ["A","B","C"]
    }
}
```

You can also view the log data from the command line:
```
aws logs tail /aws/events/eventbridge-logs-original
aws logs tail /aws/events/eventbridge-logs-refactored
```

Note that only INSERTs are processes, so if you invoke your Lambda functions multiple times, be sure to use a new orderId for each invocation.

## Cleanup

You must manually delete the event bus rules and targets you created so that CDK can safely delete the event bus:

```
aws logs delete-log-group --log-group-name /aws/events/eventbridge-logs-original
aws logs delete-log-group --log-group-name /aws/events/eventbridge-logs-refactored

aws events remove-targets --rule eventbridge-logs --event-bus-name OrdersEventBusOriginal --ids "1"
aws events delete-rule --name eventbridge-logs --event-bus-name OrdersEventBusOriginal

aws events remove-targets --rule eventbridge-logs --event-bus-name OrdersEventBusRefactored --ids "1"
aws events delete-rule --name eventbridge-logs --event-bus-name OrdersEventBusRefactored

cdk destroy --all
```