# Creating a rule that triggers on an Amazon Aurora event
Creating a rule that triggers on an Amazon Aurora event

Using Amazon EventBridge, you can automate AWS services and respond to system events such as application availability issues or resource changes. 

**Topics**
+ [

## Tutorial: Log DB instance state changes using Amazon EventBridge
](#log-rds-instance-state)

## Tutorial: Log DB instance state changes using Amazon EventBridge
Tutorial: Log instance state using EventBridge

In this tutorial, you create an AWS Lambda function that logs the state changes for an instance. You then create a rule that runs the function whenever there is a state change of an existing RDS DB instance. The tutorial assumes that you have a small running test instance that you can shut down temporarily.

**Important**  
Don't perform this tutorial on a running production DB instance.

**Topics**
+ [

### Step 1: Create an AWS Lambda function
](#rds-create-lambda-function)
+ [

### Step 2: Create a rule
](#rds-create-rule)
+ [

### Step 3: Test the rule
](#rds-test-rule)

### Step 1: Create an AWS Lambda function


Create a Lambda function to log the state change events. You specify this function when you create your rule.

**To create a Lambda function**

1. Open the AWS Lambda console at [https://console.aws.amazon.com/lambda/](https://console.aws.amazon.com/lambda/).

1. If you're new to Lambda, you see a welcome page. Choose **Get Started Now**. Otherwise, choose **Create function**.

1. Choose **Author from scratch**.

1. On the **Create function** page, do the following:

   1. Enter a name and description for the Lambda function. For example, name the function **RDSInstanceStateChange**. 

   1. In **Runtime**, select **Node.js 16x**. 

   1. For **Architecture**, choose **x86\$164**.

   1. For **Execution role**, do either of the following:
      + Choose **Create a new role with basic Lambda permissions**.
      + For **Existing role**, choose **Use an existing role**. Choose the role that you want to use. 

   1. Choose **Create function**.

1. On the **RDSInstanceStateChange** page, do the following:

   1. In **Code source**, select **index.js**. 

   1. In the **index.js** pane, delete the existing code.

   1. Enter the following code:

      ```
      console.log('Loading function');
      
      exports.handler = async (event, context) => {
          console.log('Received event:', JSON.stringify(event));
      };
      ```

   1. Choose **Deploy**.

### Step 2: Create a rule


Create a rule to run your Lambda function whenever you launch an Amazon RDS instance.

**To create the EventBridge rule**

1. Open the Amazon EventBridge console at [https://console.aws.amazon.com/events/](https://console.aws.amazon.com/events/).

1. In the navigation pane, choose **Rules**.

1. Choose **Create rule**.

1. Enter a name and description for the rule. For example, enter **RDSInstanceStateChangeRule**.

1. Choose **Rule with an event pattern**, and then choose **Next**.

1. For **Event source**, choose **AWS events or EventBridge partner events**.

1. Scroll down to the **Event pattern** section.

1. For **Event source**, choose **AWS services**.

1. For **AWS service**, choose **Relational Database Service (RDS)**.

1. For **Event type**, choose **RDS DB Instance Event**.

1. Leave the default event pattern. Then choose **Next**.

1. For **Target types**, choose **AWS service**.

1. For **Select a target**, choose **Lambda function**.

1. For **Function**, choose the Lambda function that you created. Then choose **Next**.

1. In **Configure tags**, choose **Next**.

1. Review the steps in your rule. Then choose **Create rule**.

### Step 3: Test the rule


To test your rule, shut down an RDS DB instance. After waiting a few minutes for the instance to shut down, verify that your Lambda function was invoked.

**To test your rule by stopping a DB instance**

1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).

1. Stop an RDS DB instance.

1. Open the Amazon EventBridge console at [https://console.aws.amazon.com/events/](https://console.aws.amazon.com/events/).

1. In the navigation pane, choose **Rules**, choose the name of the rule that you created.

1. In **Rule details**, choose **Monitoring**.

   You are redirected to the Amazon CloudWatch console. If you are not redirected, click **View the metrics in CloudWatch**.

1. In **All metrics**, choose the name of the rule that you created.

   The graph should indicate that the rule was invoked.

1. In the navigation pane, choose **Log groups**.

1. Choose the name of the log group for your Lambda function (**/aws/lambda/*function-name***).

1. Choose the name of the log stream to view the data provided by the function for the instance that you launched. You should see a received event similar to the following:

   ```
   {
       "version": "0",
       "id": "12a345b6-78c9-01d2-34e5-123f4ghi5j6k",
       "detail-type": "RDS DB Instance Event",
       "source": "aws.rds",
       "account": "111111111111",
       "time": "2021-03-19T19:34:09Z",
       "region": "us-east-1",
       "resources": [
           "arn:aws:rds:us-east-1:111111111111:db:testdb"
       ],
       "detail": {
           "EventCategories": [
               "notification"
           ],
           "SourceType": "DB_INSTANCE",
           "SourceArn": "arn:aws:rds:us-east-1:111111111111:db:testdb",
           "Date": "2021-03-19T19:34:09.293Z",
           "Message": "DB instance stopped",
           "SourceIdentifier": "testdb",
           "EventID": "RDS-EVENT-0087"
       }
   }
   ```

   For more examples of RDS events in JSON format, see [Overview of events for Aurora](working-with-events.md#rds-cloudwatch-events.sample).

1. (Optional) When you're finished, you can open the Amazon RDS console and start the instance that you stopped.