Terragrunt项目定制Provider：如何读取主配置公共输入？

核心原因 #

Terragrunt的include机制不会自动将父配置中的locals变量传递给子配置，仅会继承inputs、remote_state等顶层配置块的内容。你在根配置中已经将fin_config合并到inputs中，因此可以通过引用父配置的inputs来获取所需值。

直接解决方案：引用父配置的inputs #

修改项目级（如project1）的terragrunt.hcl，将local.fin_config替换为include.root.inputs即可访问合并后的环境配置：

include "root" {
  path = find_in_parent_folders()
}

generate "provider" {
  path      = "providers.tf"
  if_exists = "overwrite"
  contents = <<EOF
provider "azurerm" {
  features {}
  subscription_id = "abc"
  skip_provider_registration = true
  alias = "${include.root.inputs.law}"
}

provider "azurerm" {
  features {}
  subscription_id = "${include.root.inputs.sub}"
  skip_provider_registration = true
}
EOF
}

备选方案：抽离通用配置逻辑（避免重复代码） #

如果需要在多个配置中复用环境变量计算逻辑，可将通用逻辑抽离到单独的HCL文件，再在根和项目级配置中引入：

1. 创建src/environments/common.hcl，存放通用变量计算逻辑：

locals {
  wrk_path = trimsuffix(path_relative_to_include(), "/")
  all_path = "${get_parent_terragrunt_dir()}/../environments/all"
  env_path = "${get_parent_terragrunt_dir()}/../environments/${local.env}"
  
  all_config = try(read_terragrunt_config("${local.all_path}/environment.hcl").inputs, {})
  env_config = try(read_terragrunt_config("${local.env_path}/environment.hcl").inputs, {})
  fin_config = merge(local.all_config, local.env_config)
}

2. 根terragrunt.hcl中引入并使用：

include "common" {
  path = "${get_parent_terragrunt_dir()}/../environments/common.hcl"
}

remote_state {
    // 保持原有配置
}

terraform {
  // 保持原有配置
  extra_arguments "apply_environment" {
    commands = get_terraform_commands_that_need_vars()
    optional_var_files = [
      "${include.common.locals.all_path}/${include.common.locals.wrk_path}.tfvars",
      "${get_parent_terragrunt_dir()}/../environments/${local.env}/${include.common.locals.wrk_path}.tfvars"
    ]
  }
}

inputs = include.common.locals.fin_config

3. 项目级terragrunt.hcl中引入并使用：

include "root" {
  path = find_in_parent_folders()
}

include "common" {
  path = "${get_parent_terragrunt_dir()}/../../environments/common.hcl"
}

generate "provider" {
  path      = "providers.tf"
  if_exists = "overwrite"
  contents = <<EOF
provider "azurerm" {
  features {}
  subscription_id = "abc"
  skip_provider_registration = true
  alias = "${include.common.locals.fin_config.law}"
}

provider "azurerm" {
  features {}
  subscription_id = "${include.common.locals.fin_config.sub}"
  skip_provider_registration = true
}
EOF
}

优先推荐第一种方案，因为你已经在根配置中完成了fin_config的合并并传递到inputs，无需额外增加配置复杂度。

内容的提问来源于stack exchange，提问作者michasaucer