s3 backend causes issue with terraform always thinking backend configuration has changed

[paulrobello]

When using tflocal version 1.18.0 with a s3 backend every time i run a terraform command i get
Error: Backend initialization required: please run "terraform init"
Reason: Backend configuration block has changed

running init completes without error but then the very next command has same error.

This issues does not happen with version 0.17.1

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.20.0"
    }
  }
  backend "s3" {
    region  = "us-east-1"
    bucket  = "ls-iac-state-us-east-1"
    key     = "global-iac/project/lcl/terraform.tfstate"
    encrypt = true
  }
}

[lakkeger]

Hi @paulrobello,
Thanks for reaching out.
Your backend probably was set up with the now deprecated options of endpoint,iam_endpoint,sts_endpoint,dynamodb_endpoint.
tflocal from version 0.18 is generating the override file with the new options recommended by the Terraform documentation (here).
To be able to use the new version and the backend options you must "reinitialize" your backend with the -migrate-state option and Terraform will automatically migrate the existing statefile. (Or if the statefile can be dropped, you can use the -reconfigure option too.)
Alternatively you can use a terraform version <1.6 with terraform-local and the above mentioned backend options will be used.

Let us know if this has helped to resolve your issue.

[paulrobello]

My backend is setup exactly as I pasted above, no endpoints.
I use this before issuing any other commands and this command succeeds but all others say backend changed.

tflocal  init -upgrade -reconfigure

[lakkeger]

@paulrobello Can you please provide some information on your environment, as I'm unable to reproduce it?
See screenshot below with your code applied on the following versions:
MacOS 14.4
Terraform 1.5.7 -> 1.7.4 (made a switch from old to new to reproduce the error)
tflocal 0.18.0
Localstack 3.2.0

Additionally could you please provide the exact steps, command by command and the configuration of your Localstack instance?

[paulrobello]

reproducer repo created https://github.com/paulrobello/tflocal_s3_backend_bug

[cabeaulac]

Reproducer failed for me. Digging into it.

[cabeaulac]

I see the apply worked. It's the call to output that's failing.

[cabeaulac]

Ok. I see there's a dependency problem.
If you pip install this https://github.com/localstack-samples/multi-iac-devops/blob/main/devops-tooling/requirements.txt
then the issue goes away.
@lakkeger

[cabeaulac]

Confirmed. terraform-local==0.17.1 tflocal output command works. terraform-local==0.18.0 does not. See screen shot.

[cabeaulac]

Seems this needs output also.
https://github.com/localstack/terraform-local/pull/50/files#diff-cefcc5bf4701072dadd5e5562ed2158bc584429c4786694469981da508a869f7R39

[lakkeger]

This sample was useful @cabeaulac. Found the source of the error. I turned around the logic and I added an env variable to exclude a subcommand from proxying.