从列表 Terraform 中提取子网 ID

Question

我有许多 Terraform 数据源和一个这样创建的本地块

data "aws_subnets" "subs" {
  for_each = toset(["a", "b", "c"])

  filter {
    name   = "vpc-id"
    values = [data.aws_vpc.vpc.id]
  }

  filter {
    name   = "availability-zone"
    values = ["${data.aws_region.region.name}${each.key}"]
  }
}

data "aws_vpc" "vpc" {
  default = false
}

data "aws_region" "region" {}

locals {
   ids = [for az in data.aws_subnets.subs : az.ids[1]]
}

和一个输出块

output "main" {
    value = local.ids
}

但是当我运行 terraform apply 时出现错误

The given key does not identify an element in this collection value: the given index is greater than or equal to the length of the collection

当我从 locals 块中取出索引值时[1]，我可以看到输出为

  + main = [
      + [
          + "subnet-1234567f3f5d95987",
          + "subnet-123456797f61f831e",
          + "subnet-123456791ec481316",
        ],
      + [
          + "subnet-12345674da33e8064",
          + "subnet-12345676030bc7040",
        ],
      + [],
    ]

如何从此列表中提取特定子网 ID？

Answer 1

这里你必须考虑两件事：

1. 您正在使用for_each数据源，因此这意味着返回结果将具有键值对
2. 每个键的返回结果将是一个列表

为了达到你想要的效果，需要修改如下代码：

data "aws_subnets" "subs" {
  for_each = toset(["a", "b", "c"])

  filter {
    name   = "vpc-id"
    values = [data.aws_vpc.vpc.id]
  }

  filter {
    name   = "availability-zone"
    values = ["${data.aws_region.region.name}${each.key}"]
  }
}

data "aws_vpc" "vpc" {
  default = false
}

data "aws_region" "region" {}

locals {
   ids = values(data.aws_subnets.subs)[*].ids
}

这里，内置的values[1] 函数用于获取所有键的所有值。返回结果也是一个列表，因此这将是一个列表的列表。

[1] https://developer.hashicorp.com/terraform/language/functions/values