# Amazon EventBridge to Amazon CloudWatch Logs

This template creates an EventBridge event bus and rule that publishes matched events to CloudWatch Logs. In this example, the rule filters for specific attributes in the event before sending to the CloudWatch Logs target.

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/eventbridge-cloudwatch

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the [AWS Pricing page](https://aws.amazon.com/pricing/) for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

## Requirements

* [Create an AWS account](https://portal.aws.amazon.com/gp/aws/developer/registration/index.html) if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
* [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html) installed and configured
* [Git Installed](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git)
* [Terraform](https://learn.hashicorp.com/tutorials/terraform/install-cli?in=terraform/aws-get-started) installed

## Deployment Instructions

1. Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:
    ``` 
    git clone https://github.com/aws-samples/serverless-patterns
    ```
1. Change directory to the pattern directory:
    ```
    cd eventbridge-cloudwatch-terraform
    ```
1. From the command line, initialize terraform to  to downloads and installs the providers defined in the configuration:
    ```
    terraform init
    ```
1. From the command line, apply the configuration in the main.tf file:
    ```
    terraform apply
    ```
1. During the prompts:
    * Enter yes
1. Note the outputs from the deployment process. These contain the resource names and/or ARNs which are used for testing.

## How it works

The AWS SAM template deploys the resources and the IAM permissions required to run the application.

The EventBridge rule specified in `main.tf` filters the events based upon the criteria in the `aws_cloudwatch_event_rule` block. When matching events are sent to EventBridge that trigger the rule, they are delivered as a JSON event payload to CloudWatch Logs.

## Testing

Use the [AWS CLI](https://aws.amazon.com/cli/) to send a test event to EventBridge and observe the event delivered to the Lambda function:

1. Send an event to EventBridge:

```bash
aws events put-events --entries file://event.json
```

1. The event appears in the CloudWatch Logs stream in the Log Group displayed in the output of the terraform deployment:

```
{
    "version": "0",
    "id": "052a16f5-5b21-7bd4-6e41-8ab2b710997b",
    "detail-type": "message",
    "source": "demo.logs",
    "account": "123456789100",
    "time": "2022-03-08T15:01:13Z",
    "region": "us-east-1",
    "resources": [],
    "detail": {
        "message": "Hello From EventBridge!"
    }
}
```

## Cleanup
 
1. Change directory to the pattern directory:
    ```
    cd eventbridge-cloudwatch-terraform
    ```
1. Delete all created resources
    ```bash
    terraform destroy
    ```
1. During the prompts:
    * Enter yes
1. Confirm all created resources has been deleted
    ```bash
    terraform show
    ```
----
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