两个模块之间的模块组合使用条件 for_each 双向 [英] Module composition between two modules using a conditional for_each on both ways

问题描述

在我的根模块上，我声明了两个模块(paired_regions_network 和paired_regions_app)，它们都迭代了一组区域.

On my root module, I am declaring two modules (paired_regions_network and paired_regions_app), that both iterate a set of regions.

module "paired_regions_network" {
  source                  = "./modules/network"
  application_hostname    = module.paired_regions_app[each.key].website_hostname
  ...
  for_each = ( var.environment == "TEST" || var.environment == "PROD") ? { region1 = var.paired_regions.region1 } : {  }
}

module "paired_regions_app" {
  source                  = "./modules/multi-region"
  wag_public_ip           = module.paired_regions_network[each.key].wag_public_ip
  ...
  for_each = (var.environment == "TEST" || var.environment == "PROD") ? var.paired_regions : { region1 = var.paired_regions.region1 }
}

output "network_outputs" {
  value = module.paired_regions_network
}

output "app_outputs" {
  value = module.paired_regions_app
}

迭代区域声明如下:

variable "paired_regions" {
  description = "The paired regions"
  default = { 
    region1 = { 
      ...
    },
    region2 = { 
      ...
    }
  }
}

从 paired_regions_network 模块我想访问来自 paired_regions_app 模块的输出，即我想要的 website_hostname 值分配给 paired_regions_network 模块的 application_hostname 参数，如上所示.

From the paired_regions_network module I want to have access to the output coming from the paired_regions_app module, namely the website_hostname value, which I want to assign to the application_hostname parameter, of the paired_regions_network module, as shown above.

output "website_hostname" {
  value       = azurerm_app_service.was_app.default_site_hostname
  description = "The hostname of the website"
}

从 paired_regions_app 模块我想访问来自 paired_regions_network 模块的输出，即 wag_public_ip 值，我想分配给paired_regions_app模块的同名参数，如上图.

And from the paired_regions_app module I want to have access to the output coming from the paired_regions_network module, namely the wag_public_ip value, which I want to assign to the parameter with the same name, of the paired_regions_app module, as shown above.

output "wag_ip_address" {
  value       = azurerm_public_ip.network_ip.ip_address
  description = "The Public IP address that will be used by the app gateway"
}

但这会导致一个依赖循环，我无法摆脱它.错误如下:

But this causes a dependency cycle, that I can't get rid off. The error is the following:

错误:循环:...

能否在两个模块之间传递输出，而不引起依赖循环?

Can I pass the output between the two modules, without causing the dependency cycle?

推荐答案

根据@Marcin 的建议，我能够通过创建仅包含公共 IP 资源的第三个模块来克服这个问题.因此，paired_regions_app 模块将依赖于新模块，而不是依赖于 paired_regions_network 模块.paired_regions_network 将依赖于其他两个模块.除了移除 paired_regions_network 模块的输出外，代码改动如下:

As per @Marcin's advice, I was able to overcome the issue by creating a third module containing only the Public IP resource. So, the paired_regions_app module would depend on the new module instead of depending on the paired_regions_network module. The paired_regions_network would then depend on both the other two modules. Besides removing the output from the paired_regions_network module, the code changes are as follows:

根模块

module "paired_regions_ips" {
  source                  = "./modules/public-ip"
  ...
  for_each = ( var.environment == "TEST" || var.environment == "PROD") ? { region1 = var.paired_regions.region1 } : {  }
}

module "paired_regions_app" {
  source                  = "./modules/multi-region"
  wag_public_ip           = length(module.paired_regions_ips) > 0 ? (lookup(module.paired_regions_ips, each.key, "") != "" ? join("/", ["${module.paired_regions_ips[each.key].ip_obj.ip_address}", "32"]) : "" ) : ""
  ...
  for_each = (var.environment == "TEST" || var.environment == "PROD") ? var.paired_regions : { region1 = var.paired_regions.region1 }
}

module "paired_regions_network" {
  source                  = "./modules/network"
  wag_public_ip_id        = module.paired_regions_ips[each.key].ip_obj.id
  application_hostname    = module.paired_regions_app[each.key].website_hostname
  ...
  for_each = ( var.environment == "TEST" || var.environment == "PROD") ? { region1 = var.paired_regions.region1 } : {  }
}

output "network_outputs" {
  value = module.paired_regions_ips
}

output "app_outputs" {
  value = module.paired_regions_app
}

新模块

output "ip_obj" {
  value       = azurerm_public_ip.network_ip
  description = "The Public IP address"
}

---

一些备注:

• 由于 paired_regions_ips 模块与 paired_regions_app 模块相比，在 for_each 循环上的条件不同，因此我必须在获取时添加一些逻辑后者的输出
• 新模块输出一个公共 IP 对象，以便我可以访问它的 ID(来自 paired_regions_network 模块)和 IP 地址(来自 paired_regions_app模块)

• Because the paired_regions_ips module has different conditions on the for_each loop when compared to the paired_regions_app module, I had to add some logic when fetching the output from the latter
• The new module outputs a public IP object, so that I have access to both its ID (from the paired_regions_network module) and to the IP address (from the paired_regions_app module)

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