Lambda function script to list/start/stop an EC2 Instance.

aws-lambda-start-stop-instance.py

"""
Lambda function to switch on/off an ec2 instance.
Event can be passed like:
{
  "action" : "list" -> to list all the instances.
           : "start" -> to start a already set instance.
           : "stop" -> to stop a alreadt set instance.
}
"""

import json
import boto3

region = ''
ec2 = boto3.resource('ec2', region_name = region)


def list_instances():
  '''
  Lists all the ec2 instances with their state, public Ip, name etc. 
  '''
    instances = {}
    for instance in ec2.instances.all():
        tags = [i for i in instance.tags if i.get('Value') == 'Cron']  

        # if len(tags)>0:
        instances[instance.id] = {
            "type": instance.instance_type,
            "public_ip": instance.public_ip_address,
            "state": instance.state.get('Name'),
            # "tag": tags
            
            }
        
    for i in instances.items():
        print(i)
        
    return instances



def start_instance(id):
    ec2 = boto3.client('ec2')
    response = ec2.start_instances(InstanceIds=[id], DryRun = False)
    return response

def stop_instance(id):
    ec2 = boto3.client('ec2')
    response = ec2.stop_instances(InstanceIds=[id], DryRun=False)
    return response
   
def reboot_instance(INSTANCE_ID):
    ec2 = boto3.client('ec2')
    try:
        ec2.reboot_instances(InstanceIds=[INSTANCE_ID], DryRun=True)
    except Exception as e:
        if 'DryRunOperation' not in str(e):
            print("You don't have permission to reboot instancess.")
            raise
    
    try:
        response = ec2.reboot_instances(InstanceIds=[INSTANCE_ID], DryRun=False)
        print('Success', response)
    except Exception as e:
        print('Error', e)


def lambda_handler(event, context):
    # TODO implement
    
    data = {}
    print(event)
    if event.get('action') == 'list':
        data = list_instances()   
        print(data)
    
    elif event.get('action') == 'start':
        ins_id = ''
        data = start_instance(ins_id)
    
    elif event.get('action') == 'stop':
        ins_id = ''
        data = stop_instance(ins_id)
 
    return {
        'statusCode': 200,
        'body': json.dumps(data)
    }