Help to build a Lambda(part1) and integrate it into terraform(part2)

I have an existing S3 bucket, along with RDS instance, I need to build a lambda function, which will be triggered as soon as any kind of file will be dropped into s3 bucket, and it will run restore and upload the latest snapshot to RDS instance(part1) this part needs to be written using python language, and all of this needs to be integrated into the terraform code for management(part2)