Terraform For_Each：如何引用创建的资源 ID

Posted 2023-03-24

【中文标题】Terraform For_Each：如何引用创建的资源 ID

【英文标题】：Terraform For_Each: How to reference created resource 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！

ma​​in.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

【参考方案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。

【参考方案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