When we want to remove old files from S3 automatically, we use the lifecycle rules, but I don’t recommend setting them using the AWS Web Interface because, in my opinion, the whole infrastructure should be defined as code.

Thus, it is best to add a Terraform configuration for the bucket we want to clean.

We will need three things:

• the name of the bucket
• the key prefix of files we want to remove
• the number of days after which we want to clean the data

When we have all of that, we can define the lifecycle rule in Terraform:

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resource "aws_s3_bucket" "bucket" {
    bucket = "bucket_name"
    acl = "private"

    lifecycle_rule {
        id = "remove_old_files"
        enabled = true

        prefix = "key_prefix/"

        expiration {
            days = 180
        }
    }
}

In this example, I configured the expiration rule that removes files older than 180 days from the bucket bucket_name, but it applies only to the files which keys start with the prefix key_prefix/.

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