Terraform配置Google Cloud Storage时matches_prefix生命周期规则失效

我正在用Terraform给特定Google Cloud Storage（GCS）桶前缀配置生命周期规则，按照GCS文档，应该用matches_prefix = "path"来指定前缀，但执行terraform plan和terraform apply时，这个配置被忽略了，规则直接应用到了整个桶。

我的当前代码：

module "my-buckets" {
  source     = "terraform-google-modules/cloud-storage/google"
  version    = "3.2"
  project_id = var.gcp_project_id
  location   = "US"

  names  = ["operational-bucket"]
  prefix = var.env_stage # 变量已定义，当前值为dev
  versioning = {
    operational-bucket = true
  }
  randomize_suffix = false

  lifecycle_rules = [
      {
        action = {
          type = "Delete"
        }
        condition = {
          matches_prefix = "var/logs"
          age = 400
        }
      }
    ]
}

执行terraform plan的结果显示matches_prefix是空数组：

resource "google_storage_bucket" "buckets" {
        id                          = "dev-operational-bucket"
        name                        = "dev-operational-bucket"
        # (11 unchanged attributes hidden)

      + lifecycle_rule {
          + action {
              + type = "Delete"
            }

          + condition {
              + age                   = 400
              + matches_prefix        = []
              + matches_storage_class = []
              + matches_suffix        = []
              + with_state            = (known after apply)
            }
        }

        # (1 unchanged block hidden)
    }

问题出在matches_prefix的参数类型上。你使用的terraform-google-modules/cloud-storage模块（3.2版本）会直接将配置映射到Terraform官方的google_storage_bucket资源，而该资源的lifecycle_rule.condition.matches_prefix是列表类型（list(string)），支持指定多个前缀，而非单个字符串。

你当前写的是单个字符串"var/logs"，模块无法正确解析这个值，导致最终生成的配置里matches_prefix为空数组，规则也就应用到了整个桶。

只需要把matches_prefix改成数组形式即可：

condition = {
  matches_prefix = ["var/logs"]
  age = 400
}

修改后重新执行terraform plan，就能看到matches_prefix被正确设置为["var/logs"]，规则只会匹配该前缀下的对象。

内容的提问来源于stack exchange，提问作者Julia Bel