Terraform For_Each：如何引用创建的资源 ID答案

【问题标题】：Terraform For_Each: How to reference created resource IDTerraform For_Each：如何引用创建的资源 ID
【发布时间】：2021-04-15 22:18:24
【问题描述】：

我创建了一个创建 AWS 子网的模块。在模块中，我使用 for_each 循环来创建子网。我假设我可以索引给定子网的资源 ID，但似乎循环不会以可预测的顺序输出子网 ID 索引...不确定我在这里遗漏了什么。任何帮助表示赞赏！

main.tf

module "subnets" {
  source = "./modules/subnets/"
  vpc_id = aws_vpc.main.id
  subnets = [
    {
      name              = "private-1a"
      cidr_block        = "10.0.0.0/28"
      availability_zone = "us-east-1a"
    },
    {
      name              = "private-1b"
      cidr_block        = "10.0.1.0/24"
      availability_zone = "us-east-1b"
    },
    {
      name              = "public-1a"
      cidr_block        = "10.0.2.0/24"
      availability_zone = "us-east-1a"
    },
    {
      name              = "public-1b"
      cidr_block        = "10.0.3.0/24"
      availability_zone = "us-east-1b"
    }
  ]
}


output "private1a" {
  value = module.security_subnets.subnet_id[0]
} 
output "private1b" {
  value = module.security_subnets.subnet_id[1]
} 
output "public1a" {
  value = module.security_subnets.subnet_id[2]
} 
output "public1b" {
  value = module.security_subnets.subnet_id[3]
}

模块

locals {
  subnets = {
    for i in var.subnets :
    i.name => i
  }
}

resource "aws_subnet" "main" {
  for_each          = local.subnets
  vpc_id            = var.vpc_id
  cidr_block        = each.value.cidr_block
  availability_zone = each.value.availability_zone

  tags = merge(
    {
      "Name" = format("%s", each.value.name)
    }
  )

}

output subnet_id {
  value = values(aws_subnet.main)[*].id
}

【问题讨论】：

标签： amazon-web-services terraform terraform-provider-aws

【解决方案1】：

作为一般规则，依赖于返回项目的顺序不是一个好习惯，因为如果您决定在两者之间添加某些内容或删除某些内容，这可能会导致将来出现问题。 p>

尽管如此，在您的情况下，返回项目的顺序是定义明确的。由于您使用的是values，因此顺序为：

这些值由其对应的键以字典顺序返回，因此这些值的返回顺序与它们的键从键返回的顺序相同。

【讨论】：

【解决方案2】：

subnets 变量使用映射结构而不是数组应该按索引返回值，然后解决如果顺序更改（例如删除项目）时混合值的问题：

module "subnets" {
  source = "./modules/subnets/"
  vpc_id = aws_vpc.main.id
  subnets = {
    "private-1a" = {
      name              = "private-1a"
      cidr_block        = "10.0.0.0/28"
      availability_zone = "us-east-1a"
    },
    "private-1b" = {
      name              = "private-1b"
      cidr_block        = "10.0.1.0/24"
      availability_zone = "us-east-1b"
    },
    "public-1a" = {
      name              = "public-1a"
      cidr_block        = "10.0.2.0/24"
      availability_zone = "us-east-1a"
    },
    "public-1b" = {
      name              = "public-1b"
      cidr_block        = "10.0.3.0/24"
      availability_zone = "us-east-1b"
    }
  }
}


output "private1a" {
  value = module.security_subnets.subnet_id["private-1a"]
} 

// and so on

【讨论】：