azure - Terraform:具有多个条件内容的动态 block

Question

我正在尝试使用动态 block 为 azure cdn frontdoor 规则创建一个模块:

最初，模块是这样的:

resource "azurerm_cdn_frontdoor_rule" "main" {
  name                      = var.cdn_frontdoor_rule_name
  cdn_frontdoor_rule_set_id = var.cdn_frontdoor_rule_set_id
  order                     = var.cdn_frontdoor_rule_order
  behavior_on_match         = var.cdn_frontdoor_rule_behavior_on_match

  dynamic "conditions" {
    for_each = var.conditions_settings
    content {
      host_name_condition {
        operator         = conditions.value["host_name_operator"]
        negate_condition = conditions.value["host_name_negate_condition"]
        match_values     = conditions.value["host_name_match_values"]
        transforms       = conditions.value["host_name_transforms"]
      }
    }
  }
}

但现在我想添加其他内容:

resource "azurerm_cdn_frontdoor_rule" "main" {
  name                      = var.cdn_frontdoor_rule_name
  cdn_frontdoor_rule_set_id = var.cdn_frontdoor_rule_set_id
  order                     = var.cdn_frontdoor_rule_order
  behavior_on_match         = var.cdn_frontdoor_rule_behavior_on_match

  dynamic "conditions" {
    for_each = var.conditions_settings
    content {
      host_name_condition {
        operator         = conditions.value["host_name_operator"]
        negate_condition = conditions.value["host_name_negate_condition"]
        match_values     = conditions.value["host_name_match_values"]
        transforms       = conditions.value["host_name_transforms"]
      }
      is_device_condition {
        operator         = conditions.value["is_device_operator"]
        negate_condition = conditions.value["is_device_negate_condition"]
        match_values     = conditions.value["is_device_match_values"]
      }
      post_args_condition {
        post_args_name = conditions.value["post_args_name"]
        operator       = conditions.value["post_args_operator"]
        match_values   = conditions.value["post_args_match_values"]
        transforms     = conditions.value["post_args_transforms"]
      }
    }
  }
}

但是当我运行这个时，我收到以下错误:

╷
│ Error: Missing required argument
│ 
│   with module.cdn_frontdoor_rule_set_spa_rule_1.azurerm_cdn_frontdoor_rule.main,
│   on ../../../modules/azure/cdn-frontdoor-rule/main.tf line 1, in resource "azurerm_cdn_frontdoor_rule" "main":
│    1: resource "azurerm_cdn_frontdoor_rule" "main" {
│ 
│ The argument "conditions.0.post_args_condition.0.post_args_name" is required, but no definition was found.
╵
╷
│ Error: Missing required argument
│ 
│   with module.cdn_frontdoor_rule_set_spa_rule_1.azurerm_cdn_frontdoor_rule.main,
│   on ../../../modules/azure/cdn-frontdoor-rule/main.tf line 1, in resource "azurerm_cdn_frontdoor_rule" "main":
│    1: resource "azurerm_cdn_frontdoor_rule" "main" {
│ 
│ The argument "conditions.0.post_args_condition.0.operator" is required, but no definition was found.
╵
╷
│ Error: Missing required argument
│ 
│   with module.cdn_frontdoor_rule_set_spa_rule_1.azurerm_cdn_frontdoor_rule.main,
│   on ../../../modules/azure/cdn-frontdoor-rule/main.tf line 1, in resource "azurerm_cdn_frontdoor_rule" "main":
│    1: resource "azurerm_cdn_frontdoor_rule" "main" {
│ 
│ The argument "conditions.0.url_filename_condition.0.operator" is required, but no definition was found.

我也尝试过这个:

resource "azurerm_cdn_frontdoor_rule" "main" {
  name                      = var.cdn_frontdoor_rule_name
  cdn_frontdoor_rule_set_id = var.cdn_frontdoor_rule_set_id
  order                     = var.cdn_frontdoor_rule_order
  behavior_on_match         = var.cdn_frontdoor_rule_behavior_on_match

  dynamic "conditions" {
    for_each = var.conditions_settings
    content {
      host_name_condition {
        operator         = conditions.value["host_name_operator"]
        negate_condition = conditions.value["host_name_negate_condition"]
        match_values     = conditions.value["host_name_match_values"]
        transforms       = conditions.value["host_name_transforms"]
      }
    }
    content {
      is_device_condition {
        operator         = conditions.value["is_device_operator"]
        negate_condition = conditions.value["is_device_negate_condition"]
        match_values     = conditions.value["is_device_match_values"]
      }
    }
    content {
      post_args_condition {
        post_args_name = conditions.value["post_args_name"]
        operator       = conditions.value["post_args_operator"]
        match_values   = conditions.value["post_args_match_values"]
        transforms     = conditions.value["post_args_transforms"]
      }
    }
  }
}

但我也收到以下错误:

│ Error: Extraneous dynamic content block
│ 
│   on ../../../modules/azure/cdn-frontdoor-rule/main.tf line 50, in resource "azurerm_cdn_frontdoor_rule" "main":
│   50:     content {
│ 
│ Only one nested content block is allowed for each dynamic block.

如何修复动态 block 内容，使其具有条件性，从而允许有条件地选择内容？

Answer 1

来自引用the documentation for this resource type似乎可以在 conditions block 中使用条件类型 block 的任意组合，但如果您包含任何特定的 block 类型，则必须在其中填充某些参数。

考虑到该结构，我建议使用嵌套结构，其中输入变量反射(reflect)与资源类型的配置架构使用的类似层次结构:

variable "conditions" {
  type = object({
    host_name = optional(set(object({
      operator         = string
      match_values     = optional(list(string))
      transforms       = optional(list(string))
      negate_condition = optional(bool)
    })), [])
    is_device = optional(set(object({
      operator         = string
      match_values     = optional(list(string))
      negate_condition = optional(bool)
    })), [])
  })
  default = {}
}

上面的声明要求一个对象类型，每个条件类型都有一个属性，所有这些都是可选的。如果未设置，Terraform 将使用空集作为其默认值。整个变量的默认值是一个具有所有属性默认值的对象，因此默认情况下它们都是空集。

从资源类型文档中并不清楚内部根本没有嵌套 block 的 condition block 是否有效。以防万一，您可以导出所有类型的所有条件的总数，用作是否包含 conditions block 的条件:

locals {
  total_conditions_count = sum([
    for s in var.conditions : length(s)
  ]...)
}

这使用 sum与 for expression首先计算每个集合中元素的数量，然后将所有这些元素加在一起以找到总数。因此，如果 var.conditions 中没有指定条件，则该值将为零。

有了这些支持声明，您就可以声明资源本身:

resource "azurerm_cdn_frontdoor_rule" "main" {
  name                      = var.cdn_frontdoor_rule_name
  cdn_frontdoor_rule_set_id = var.cdn_frontdoor_rule_set_id
  order                     = var.cdn_frontdoor_rule_order
  behavior_on_match         = var.cdn_frontdoor_rule_behavior_on_match

  dynamic "conditions" {
    for_each = local.total_conditions_count > 0 ? [var.conditions] : []
    content {
      dynamic "host_name_condition" {
        for_each = conditions.value.host_name
        content {
          operator         = host_name_condition.value.operator
          negate_condition = host_name_condition.value.negate_condition
          match_values     = host_name_condition.value.match_values
          transforms       = host_name_condition.value.transforms
        }
      }
      dynamic "is_device_condition" {
        for_each = conditions.value.is_device
        content {
          operator         = is_device_condition.value.operator
          negate_condition = is_device_condition.value.negate_condition
          match_values     = is_device_condition.value.match_values
        }
      }
    }
  }
}

现在使用两级动态 block 。 动态“conditions” block 声明，如果 var.conditions 中至少给出了一个条件，则应该只有一个 conditions block 。如果该条件通过，则每个嵌套动态 block 都会生成每个受支持条件类型的零个或多个 block 。重要的是，如果没有特定类型的条件，那么它将生成零个该类型的 block ，从而避免在存在 block 后需要某些参数时遇到的错误。

调用此模块时，您的用户会将条件指定为嵌套数据结构。例如:

module "example" {
  source = "../example"

  conditions = {
    host_name = [
      {
        operator = "Equal"
        match_values = [
          "www.contoso.com",
          "images.contoso.com",
          "video.contoso.com",
        ]
        transforms = ["Lowercase", "Trim"]
      },
    ]
    is_device = [
      {
        operator     = "Equal"
        match_values = ["Mobile"]
      },
    ]
  }
}

这种嵌套结构的主要优点是变量的类型约束反射(reflect)了与底层资源类型相同的必需和可选参数，因此类型约束确保用户输入始终对资源类型有效，包括生成如果有人在调用模块时定义条件时忘记设置运算符，则会出现与您在模块内部看到的类似错误。