Terraform optional provider for optional resource - terraform

Question

I have a module where I want to conditionally create an s3 bucket in another region. I tried something like this:
resource "aws_s3_bucket" "backup" {
count = local.has_backup ? 1 : 0
provider = "aws.backup"
bucket = "${var.bucket_name}-backup"
versioning {
enabled = true
}
}
but it appears that I need to provide the aws.backup provider even if count is 0. Is there any way around this?
NOTE: this wouldn't be a problem if I could use a single provider to create buckets in multiple regions, see https://github.com/terraform-providers/terraform-provider-aws/issues/8853

Answer 1

Based on your description, I understand that you want to create resources using the same "profile", but in a different region.
For that case I would take the following approach:
Create a module file for you s3_bucket_backup, in that file you will build your "backup provider" with variables.
# Module file for s3_bucket_backup
provider "aws" {
region = var.region
profile = var.profile
alias = "backup"
}
variable "profile" {
type = string
description = "AWS profile"
}
variable "region" {
type = string
description = "AWS profile"
}
variable "has_backup" {
type = bool
description = "AWS profile"
}
variable "bucket_name" {
type = string
description = "VPC name"
}
resource "aws_s3_bucket" "backup" {
count = var.has_backup ? 1 : 0
provider = aws.backup
bucket = "${var.bucket_name}-backup"
}
In your main tf file, declare your provider profile using local variables, call the module passing the profile and a different region
# Main tf file
provider "aws" {
region = "us-east-1"
profile = local.profile
}
locals {
profile = "default"
has_backup = false
}
module "s3_backup" {
source = "./module"
profile = local.profile
region = "us-east-2"
has_backup = true
bucket_name = "my-bucket-name"
}
And there you have it, you can now build your s3_bucket_backup using the same "profile" with different regions.
In the case above, the region used by the main file is us-east-1 and the bucket is created on us-east-2.
If you set has_backup to false, it won't create anything.
Since the "backup provider" is build inside the module, your code won't look "dirty" for having multiple providers in the main tf file.