Email notification through SNS and Lambda

I am facing an issue. My main motive is to send an email whenever there is state change happened to ec2 instances.

I tried cloud watch events directly with SNS and its work also but the email template which I am receiving is not having the proper information to understood.

I was expecting Server name and its IP in the email template which SNS does not give me the option to modify it. So What I am thinking is to involve lambda so that

Let me know if you think this is correct method for what I am expecting or not. and give some insights on how to get Lambda in between Cloud watch and SNS

Thanks & Regards

1 Answer
1

As shown in the Amazon CloudWatch Events console, a sample event triggered by an instance state change is:


"version": "0",
"id": "7bf73129-1428-4cd3-a780-95db273d1602",
"detail-type": "EC2 Instance State-change Notification",
"source": "aws.ec2",
"account": "123456789012",
"time": "2015-11-11T21:29:54Z",
"region": "us-east-1",
"resources": [
"arn:aws:ec2:us-east-1:123456789012:instance/i-abcd1111"
],
"detail":
"instance-id": "i-abcd1111",
"state": "pending"




CloudWatch events can then directly trigger an AWS Lambda function, passing in this information.

The Lambda function can use the Instance ID to retrieve further details about the instance (eg server name, IP address).

The function can then either:

Using SNS would be the easiest, if you don't mind the text-based content.

Here is some sample code that will receive an event from Amazon CloudWatch Events when an instance changes state, then send a message to an Amazon SNS topic with further details:

import boto3

def lambda_handler(event, context):

# Extract Instance ID from event
instance_id = event['detail']['instance-id']

# Obtain information about the instance
ec2_client = boto3.client('ec2')
instance_info = ec2_client.describe_instances(InstanceIds=[instance_id])
instance = instance_info['Reservations'][0]['Instances'][0]

# Extract name tag
name_tags = [t['Value'] for t in instance['Tags'] if t['Key']=='Name']
name = name_tags[0] if name_tags is not None else ''

# Send message to SNS
MY_SNS_TOPIC_ARN = 'arn:aws:sns:ap-southeast-2:123456789012:foo'
sns_client = boto3.client('sns')
sns_client.publish(
TopicArn = MY_SNS_TOPIC_ARN,
Subject = 'Instance Change State: ' + instance_id,
Message = 'Instance: ' + instance_id + ' has changed staten' +
'State: ' + instance['State']['Name'] + 'n' +
'IP Address: ' + instance['PublicIpAddress'] + 'n' +
'Name: ' + name
)


To setup:

describe_instances

publish

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