Terraform AWS optional logging for S3 bucket - amazon-s3

Question

I am trying to create S3 bucket using terraform from examples in the link
https://www.terraform.io/docs/providers/aws/r/s3_bucket.html
I have created a S3 module.
The issue i am facing is, for certain bucket i do not want logging enabled.
How can this be accomplished in terraform.
logging {
target_bucket = "${aws_s3_bucket.log_bucket.id}"
target_prefix = "log/"
}
Using empty string for target_bucket and target_prefix causes terraform to make an attempt to create target_bucket.
Also, i am trying to use a module.

Answer 1

Using the newer dynamic block support in terraform 0.12+ we pass a single-item array containing the logging settings if we want logging like so:
variable "logging" {
type = list
default = []
description = "to enable logging set this to [{target_bucket = 'xxx' target_prefix = 'logs/'}]"
}
resource "aws_s3_bucket" "s3bucket" {
dynamic "logging" {
for_each = [for l in var.logging : {
target_bucket = l.target_bucket
target_prefix = l.target_prefix
}]
content {
target_bucket = logging.value.target_bucket
target_prefix = logging.value.target_prefix
}
}
}

Answer 2

Can Fly.
If you want to make the values of logging optional, first make your module aws_s3_bucket.tf:
resource "aws_s3_bucket" "b" {
bucket = "my-tf-test-bucket"
acl = "private"
logging = "${var.logging}"
}
variable "logging" {
type = "list"
default = []
}
then in a sub-folder example add your template module.tf:
module "s3" {
source = "../"
logging = [
{
target_bucket = "loggingbucketname"
target_prefix = "log/"
},
]
}
provider "aws" {
region = "eu-west-1"
version = "2.4.0"
}
This is your version that has logging.
Next modify your module.tf to look like
module "s3" {
source = "../"
}
provider "aws" {
region = "eu-west-1"
version = "2.4.0"
}
That's your version without. This worked with:
Terraform v0.11.11
+ provider.aws v2.4.0
Updated
This is answer for v0.12.5.
module is now:
resource "aws_s3_bucket" "b" {
bucket = "my-tf-test-bucket"
acl = "private"
logging {
target_bucket = var.logging["target_bucket"]
target_prefix = var.logging["target_prefix"]
}
}
variable "logging" {
type=map
default={
target_bucket = ""
target_prefix = ""
}
}
Use module with logging becomes (your path to modules might differ):
module "s3" {
source = "../"
logging={
target_bucket = aws_s3_bucket.log_bucket.id
target_prefix = "log/"
}
}
provider "aws" {
region = "eu-west-1"
version = "2.34.0"
}
resource "aws_s3_bucket" "log_bucket" {
bucket = "my-tf-log-bucket"
acl = "private"
}
and without:
module "s3" {
source = "../"
}
provider "aws" {
region = "eu-west-1"
version = "2.34.0"
}