Email S3 Objects as Attachment

The following post will help you to email objects (files, images etc.) from s3 as soon as they are uploaded. We will be using S3 events to triggers Lambda function which will download and email the file using SES.

If the S3 buckets doesn’t exist already, create a bucket and an IAM role with below permissions, for this demo we are using permissions which are wide open, these should be restricted.

Naviagte to SES and verify an email address, this will be used in Lambda function to send emails. Click on to verify a new Email Addres and follow the instructions.

Navigate to Lambda and create a function, use python 3.7 and assign the role we created earlier which had s3, ses and cloudwatch logs permissions to the lambda function. Use the below code in the function, add the TO email addresses.

import os.path
import boto3
import email
from botocore.exceptions import ClientError
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication
s3 = boto3.client("s3")
def lambda_handler(event, context):
    
    SENDER = "abc@abc.com"
    RECIPIENT = "efg@efg.com"
AWS_REGION = "us-west-2"
    SUBJECT = "Email From S3"
FILEOBJ = event["Records"][0]
    BUCKET_NAME = str(FILEOBJ['s3']['bucket']['name'])
    KEY = str(FILEOBJ['s3']['object']['key'])
FILE_NAME = os.path.basename(KEY)
TMP_FILE_NAME = '/tmp/' + FILE_NAME
s3.download_file(BUCKET_NAME, KEY, TMP_FILE_NAME)
    ATTACHMENT = TMP_FILE_NAME
BODY_TEXT = "The Object file was uploaded to S3"
client = boto3.client('ses',region_name=AWS_REGION)
msg = MIMEMultipart()
    # Add subject, from and to lines.
    msg['Subject'] = SUBJECT 
    msg['From'] = SENDER 
    msg['To'] = RECIPIENT
textpart = MIMEText(BODY_TEXT)
    msg.attach(textpart)
    att = MIMEApplication(open(ATTACHMENT, 'rb').read())
    att.add_header('Content-Disposition','attachment',filename=ATTACHMENT)
    msg.attach(att)
    print(msg)
    try:
        response = client.send_raw_email(
            Source=SENDER,
            Destinations=['abc@abc.com','xyz@xyz.com'],
            RawMessage={ 'Data':msg.as_string() }
        )
    except ClientError as e:
        print(e.response['Error']['Message'])
    else:
        print("Email sent! Message ID:",response['MessageId'])

Go back to S3 bucket -> Properties -> Events -> Add notifications

Give a Name, select PUT in events , select lambda in Send to and from the drop down select the lambda function. These changes will trigger the lambda function as soon as there is a PUT (object upload to S3).

The trigger will send an email to the TO address defined in the function, to check logs navigate to Cloudwatch logs and search for “/aws/lambda/functionname”.