<!--
title: Serverless Framework - AWS Lambda Events - CloudWatch Event
menuText: CloudWatch Event
menuOrder: 13
description:  Setting up AWS CloudWatch Events with AWS Lambda via the Serverless Framework
layout: Doc
-->

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### [Read this on the main serverless docs site](https://www.serverless.com/framework/docs/providers/aws/events/cloudwatch-event)

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# CloudWatch Event

## Simple event definition

This will enable your Lambda function to be called by an EC2 event rule.
Please check the page of [Event Types for CloudWatch Events](http://docs.aws.amazon.com/AmazonCloudWatch/latest/events/EventTypes.html).

```yml
functions:
  myCloudWatch:
    handler: myCloudWatch.handler
    events:
      - cloudwatchEvent:
          event:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
```

## Enabling / Disabling

**Note:** `cloudwatchEvent` events are enabled by default.

This will create and attach a disabled `cloudwatchEvent` event for the `myCloudWatch` function.

```yml
functions:
  myCloudWatch:
    handler: myCloudWatch.handler
    events:
      - cloudwatchEvent:
          event:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
          enabled: false
```

## Specify Input or Inputpath

You can specify input values ​​to the Lambda function.

```yml
functions:
  myCloudWatch:
    handler: myCloudWatch.handler
    events:
      - cloudwatchEvent:
          event:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
          input:
            key1: value1
            key2: value2
            stageParams:
              stage: dev
      - cloudwatchEvent:
          event:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
          inputPath: '$.stageVariables'
      - cloudwatchEvent:
          event:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
          inputTransformer:
            inputPathsMap:
              eventTime: '$.time'
            inputTemplate: '{"time": <eventTime>, "key1": "value1"}'
```

## Specifying a Description

You can also specify a CloudWatch Event description.

```yml
functions:
  myCloudWatch:
    handler: myCloudWatch.handler
    events:
      - cloudwatchEvent:
          description: 'CloudWatch Event triggered on EC2 Instance pending state'
          event:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
```

## Specifying a Name

You can also specify a CloudWatch Event name. Keep in mind that the name must begin with a letter; contain only ASCII letters, digits, and hyphens; and not end with a hyphen or contain two consecutive hyphens. More information [here](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-name.html).

```yml
functions:
  myCloudWatch:
    handler: myCloudWatch.handler
    events:
      - cloudwatchEvent:
          name: 'my-cloudwatch-event-name'
          event:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
```