AWS Lambda to stop an ec2 instance

First you need to set up a role to execute lambda functions and also ec2 instance functions.

Second you need to get your ec2 instance ids.

Python 2.7

import boto3
# Enter the region your instances are in. Include only the region without specifying Availability Zone; e.g., 'us-east-1'
region = 'us-west-2'
# Enter your instances here: ex. ['X-XXXXXXXX', 'X-XXXXXXXX']
instances = ['i-028f37b8a9749dd9a']

def lambda_handler(event, context):
    ec2 = boto3.client('ec2', region_name=region)
    ec2.stop_instances(InstanceIds=instances)
    print 'stopped your instances: ' + str(instances)

Java 8

public class ActionHandler implements RequestHandler<Object, String> {
	
	AmazonEc2Service amazonEc2Service = new AmazonEc2Service();
	
	@Override
	public String handleRequest(Object input, Context context) {
		context.getLogger().log("Input: " + input);
		
		amazonEc2Service.stopSilverInstances();
		
		return "Hello from Lambda!";
	}

}

public class AmazonEc2Service {

	private AwsConfig awsConfig;
	
	private final List<String> ids = Arrays.asList("i-028f37b8a9749dd9a","i-057fc46fb31c7214e");

	public AmazonEc2Service() {
		awsConfig = new AwsConfig();
	}

	public void stopSilverInstances() {
		System.out.println("stopSilverInstances()");
		AmazonEC2 amazonEC2 = awsConfig.getAmazonEC2();
		
		StopInstancesRequest request = new StopInstancesRequest()
				.withInstanceIds(ids);
		
		ObjectNode msg = ObjectUtils.getObjectNode();

		StopInstancesResult result = amazonEC2.stopInstances(request);
		
		
		
		System.out.println("done stopSilverInstances!");
	}
}

public class AwsConfig {
	
	private final String amazonAWSAccessKey = ""; 
    private final String amazonAWSSecretKey = ""; 
    
    private AWSCredentialsProvider amazonAWSCredentialsProvider;
    
    
 
    public AwsConfig() { 
        amazonAWSCredentialsProvider = new AWSStaticCredentialsProvider(new BasicAWSCredentials(amazonAWSAccessKey, amazonAWSSecretKey));
    } 
    
    public AmazonEC2 getAmazonEC2() {
    	AmazonEC2 client = AmazonEC2ClientBuilder.standard().withCredentials(amazonAWSCredentialsProvider)
    	.withRegion(Regions.US_WEST_2).build();
    	
    	return client;
    }
}

Bring down ecs instances for off hours

#!/usr/bin/env python
"""
A Lambda Function to set the desired count of running tasks
in a service based on a cluster's containter instances.
Designed to be triggered by a CloudWatch Event rule.
"""
from __future__ import print_function

import os
import json
import boto3


def ecs_client():
    return boto3.client("ecs")


def adjust_service_desired_count(ecs_client, cluster, service, desiredCount):
    running_service = ecs_client.describe_services(cluster=cluster, services=[service])

    if not running_service["services"]:
        print("SKIP: Service not found in cluster {}".format(cluster))
        return

    desired_task_count = running_service["services"][0]["desiredCount"]

    clusters = ecs_client.describe_clusters(clusters=[cluster])
    registered_instances = clusters["clusters"][0]["registeredContainerInstancesCount"]

    if desired_task_count != desiredCount:
        print("Adjusting cluster '{}' to run {} tasks of service '{}'".format(
            cluster, desiredCount, service
        ))
        response = ecs_client.update_service(
            cluster=cluster,
            service=service,
            desiredCount=desiredCount,
        )

        print(response)
        return response

    # Do nothing otherwise
    print("SKIP: Cluster {} has {} desired tasks for {} registered instances.".format(
        cluster, desired_task_count, registered_instances
    ))
    return


def lambda_handler(event, context):
    cluster_service_mapping = {
        'api-cluster': [
          'arn:aws:ecs:us-east-1:{account-id}:service/api-auth-service',
          'arn:aws:ecs:us-east-1:{account-id}:service/api-account-service'
        ]
    }
        
    desired_count = int(os.getenv('DESIRED_COUNT'))
    
    for cluster, services in cluster_service_mapping.items():
        for service in services:
            adjust_service_desired_count(ecs_client(), cluster, service, desired_count)

    print("DONE")
    return {
        "statusCode": 200,
        "body": json.dumps({ "message": "success" })
    }