Lambda (S3) Bucket Upload

A simple lambda application that will send an email when any file uploaded to a bucket (S3).

• Go to AWS Lambda Console and hit the button Create a function
• Choose Author from scratch
• Runtime choose Python 3.x (I'm using Python 3.10)
• In execution role mark the Create a new role with basic Lambda permissions
• Click on Create a function

• Before, we need to create an identity in Amazon Simple Email Service Console and create identity, choose email and create (you need to verify the email in your mailbox)
• Go back to the lambda function → Configurations → Permissions and click on the role name id. Go to Add permissions → Attach policies and give the permissions: AmazonSESFullAccess - AmazonS3FullAccess

• In the lambda console, click on Add trigger in Select source choose S3 and create it

• When we upload any file to the bucket, it will trigger our lambda function and send an email. I'll use lambda_function.py

import json
import urllib.parse
import boto3

print("Loading lambda function...")

s3 = boto3.client("s3")
ses = boto3.client("ses")

def lambda_handler(event, context):
    
    bucket = event["Records"][0]["s3"]["bucket"]["name"]
    print(bucket)
    key = urllib.parse.unquote_plus(event["Records"][0]["s3"]["object"]["key"], encoding="utf-8")
    try:
        response = s3.get_object(Bucket=bucket, Key=key)
        print("Content Type: " + response["ContentType"])
        subject = "Email from AWS Trigger"
        body = "A file was uploaded in your bucket"
        message = {"Subject": {"Data": subject}, "Body": {"Html": {"Data":body}}}
        res = ses.send_email(Source="<your_email_here>",
                             Destination={"ToAddresses": ["<your_email_here>"]},
                             Message=message)
        return response["ContentType"]
    
    except Exception as e:
        print(e)

• Copy and paste the code above in the code and click on deploy

• I'll upload a file hello_lambda.txt using the S3 Console. When hit the upload button, an email will be sent to my mailbox.

• The email received after upload the file in S3:

• Optional: You can check the Logs in Monitor → View CloudWatch logs

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Created by BrenoAV