Generating backend & provider config

Stop copy-pasting boilerplate.

The single biggest boilerplate in multi-module Terraform is the backend block — every root module needs one, and they are nearly identical except for the state key. Terragrunt’s generate and remote_state features produce that config so you write it once. remote_state defines the backend for a unit (and can live in a parent file every unit inherits), and Terragrunt writes the corresponding backend.tf into the generated module at run time.

remote_state {
  backend = "s3"
  generate = { path = "backend.tf", if_exists = "overwrite" }
  config = {
    bucket         = "acme-tf-state"
    key            = "${path_relative_to_include()}/terraform.tfstate"  # unique per unit
    region         = "us-east-1"
    dynamodb_table = "tf-locks"
    encrypt        = true
  }
}

Generating provider config too

The same generate mechanism produces provider blocks — a common provider.tf (with the right region, assume-role, default tags) injected into every unit, so you configure the provider once instead of in every module. The key trick above is path_relative_to_include(), which gives each unit a distinct state key automatically based on its folder, so you never hand-assign state paths again.

generate "provider" {
  path      = "provider.tf"
  if_exists = "overwrite"
  contents  = <<EOF
provider "aws" {
  region = "us-east-1"
  default_tags { tags = { managed_by = "terragrunt" } }
}
EOF
}