Can't find variables in attempted multi-cloud (AWS / Azure) configuration

[antgel]

Hi all, I want to use one repo for AWS and Azure. Common stuff in root.hcl, cloud-specific stuff in providers.hcl etc. The Azure stuff is fine, the problem is aws/providers.hcl tries to use variables from root.hcl and can't find them. What am I doing wrong? How should I implement this?

Error: Attempt to get attribute from null value aws/providers.hcl , in remote_state: 
bucket         = "terraform-state-${local.account_name}-${local.region}" 

This value is null, so it does not have any attributes.


# aws/main/us-east-1/staging/erp/terragrunt.hcl:

terraform {
  source = "git::[email protected]:foo-creative/foo-tf-modules.git//erp"
}

include {
  path = find_in_parent_folders("root.hcl")
}


# aws/main/us-east-1/staging/env.hcl

locals {
  environment = "staging"
}


# aws/main/us-east-1/region.hcl:

locals {
  region   = "us-east-1"
}


# aws/main/account.hcl:

locals {
  account_name   = "main"
  aws_account_id = "123456789"
}


# aws/providers.hcl:

generate "provider" {
  path      = "provider.tf"
  if_exists = "overwrite_terragrunt"
  contents  = <<EOF
provider "aws" {
  region = "${local.region}"

  allowed_account_ids = ["${local.account_id}"]
  default_tags {
    tags = {
      environment = "${local.environment}"
      terraformed = "true"
    }
  }
}
EOF
}

remote_state {
  backend = "s3"
  config = {
    bucket         = "foo-terraform-state-${local.account_name}-${local.region}"  # ERROR HERE
    dynamodb_table = "terraform-locks"
    encrypt        = true
    key            = "${path_relative_to_include()}/terraform.tfstate"
    region         = local.region
  }
  generate = {
    path      = "backend.tf"
    if_exists = "overwrite_terragrunt"
  }
}

[yhakbar]

It's unclear what your root.hcl looks like.

I think you might be looking to do something like:

# aws/providers.hcl
locals {
  region = read_terragrunt_config(find_in_parent_folders("region.hcl")).locals.region
}

# aws/main/us-east-1/staging/erp/terragrunt.hcl:

terraform {
  source = "git::[email protected]:foo-creative/foo-tf-modules.git//erp"
}

include "root" {
  path = find_in_parent_folders("root.hcl")
}

include "providers" {
  path = find_in_parent_folders("providers.hcl")
}

[antgel]

@yhakbar Really appreciate you getting back to me, thank you! I noticed that I forgot to include the contents of root.hcl which is included from aws/main/us-east-1/staging/erp/terragrunt.hcl with the following code:

include {
  path = find_in_parent_folders("root.hcl")
}

I have copied root.hcl below. The idea is to include account / providers / region / env one time only, not from every individual module.

Is the problem potentially that the find_in_parent_folders calls in root.hcl won't work because the implication is parent folders of the root where root.hcl is located (there are none!), or parent folders of the directory where the code is being run from i.e. aws/main/us-east-1/staging/erp/. I have assumed the latter but if it's the former none of this will work.

locals {
  account_vars = read_terragrunt_config(find_in_parent_folders("account.hcl"))
  provider_vars = read_terragrunt_config(find_in_parent_folders("providers.hcl"))
  region_vars = read_terragrunt_config(find_in_parent_folders("region.hcl"))
  environment_vars = read_terragrunt_config(find_in_parent_folders("env.hcl"))

  account_name = local.account_vars.locals.account_name
  account_id   = local.account_vars.locals.account_id
  environment  = local.environment_vars.locals.environment
  region       = local.region_vars.locals.region
}

inputs = merge(
  local.provider_vars.locals,
  local.region_vars.locals,
  local.environment_vars.locals,
  {
    env_region_dash = "${local.environment}-${local.region}"
    env_region_dot  = "${local.environment}.${local.region}"
    region_env_dash = "${local.region}-${local.environment}"
    region_env_dot  = "${local.region}.${local.environment}"
  }
)

[antgel]

@yhakbar Hi, did you see my extra comment above with root.hcl? Any thoughts?

[yhakbar]

Hey @antgel

There's a subtle difference between reading and including Terragrunt configurations.

You can learn more about reading with read_terragrunt_config here.

Note that the example we show there is exactly using one shared read_terragrunt_config from a common root.hcl.

That will allow you to read and use a given HCL configuration as a variable. It won't merge those configurations into your account unit, however. That is done with an include.

You can't chain includes, so your options are to either use two includes in your unit to have a common generate block shared for everything in that directory, or use the data read using read_terragrunt_config in the root.hcl.

e.g. read the configuration you want to generate, but put the actual generate block in root.hcl.

Let me know if that helps.