在 Terraform 变量中使用 JSON 格式的字符串

Question

我正在 Terraform 版本 0.14.15 上使用 for_each 方法创建一些资源。该资源有一个属性 input_parameters，它将 JSON 格式的字符串作为其值。我正在使用单独的对象在地图变量中定义这个值。我指定为 JSON 格式的字符串的值，执行时出现错误，我需要声明一个字符串。任何有关修复此错误的见解都会有所帮助。下面是我声明资源和变量的方式。

资源

resource "aws_config_config_rule" "managed_rules" {
  for_each         = var.managed_rules
  name             = each.value.name
  description      = each.value.description
  input_parameters = each.value.input_parameters

  source {
    owner             = each.value.owner
    source_identifier = each.value.source_identifier
  }

  depends_on = [aws_config_configuration_recorder.config_recorder]
}

变量

variable "managed_rules" {
  type = map(object({
    name              = string
    description       = string
    owner             = string
    source_identifier = string
# Is there a variable for strings in JSON format?
    input_parameters  = string
  }))
  default = {
    "1" = {
      name              = "alb-http-to-https-redirection-check"
      description       = "Checks whether HTTP to HTTPS redirection is configured on all HTTP listeners of Application Load Balancers. The rule is NON_COMPLIANT if one or more HTTP listeners of Application Load Balancer do not have HTTP to HTTPS redirection configured."
      owner             = "AWS"
      source_identifier = "ALB_HTTP_TO_HTTPS_REDIRECTION_CHECK"
      input_parameters = {
        "MaximumExecutionFrequency" : "TwentyFour_Hours",
      }
  }

错误

This default value is not compatible with the variable's type constraint:
element "2": attribute "input_parameters": string required.

使用 jsonencode 函数更新代码并将 input_parameters 更改为 any 后，这是错误：

    This default value is not compatible with the variable's type constraint:
collection elements cannot be unified.

Answer 1

这里发生了一些事情：

1. 资源要求 input_parameters 是 JSON 编码的字符串
2. 变量类型为字符串
3. 您将对象类型传递给仅接受字符串类型的变量

所以 (2) 和 (3) 是冲突的。在某些时候，您必须将对象转换为 JSON 字符串。您可以在将其作为输入变量传递之前执行此操作，也可以将输入变量更改为接受对象并将对象提供给资源时将其转换为 JSON。

我会选择第二个选项，因为将对象而不是字符串传递到模块中更直观。所以，试试这个：

resource "aws_config_config_rule" "managed_rules" {
  for_each         = var.managed_rules
  name             = each.value.name
  description      = each.value.description
  input_parameters = jsonencode(each.value.input_parameters)

  source {
    owner             = each.value.owner
    source_identifier = each.value.source_identifier
  }

  depends_on = [aws_config_configuration_recorder.config_recorder]
}


variable "managed_rules" {
  type = map(object({
    name              = string
    description       = string
    owner             = string
    source_identifier = string
# Is there a variable for strings in JSON format?
    input_parameters  = any
  }))
  default = {
    "1" = {
      name              = "alb-http-to-https-redirection-check"
      description       = "Checks whether HTTP to HTTPS redirection is configured on all HTTP listeners of Application Load Balancers. The rule is NON_COMPLIANT if one or more HTTP listeners of Application Load Balancer do not have HTTP to HTTPS redirection configured."
      owner             = "AWS"
      source_identifier = "ALB_HTTP_TO_HTTPS_REDIRECTION_CHECK"
      input_parameters = {
        "MaximumExecutionFrequency" : "TwentyFour_Hours",
      }
  }

请注意，我在资源的input_parameters 中使用了jsonencode，并将该字段的变量类型更改为any（因此它将接受任何结构的对象）。

Answer 2

您可以按如下方式创建 json 字符串：

variable "managed_rules" {

  type = map(object({
    name              = string
    description       = string
    owner             = string
    source_identifier = string
# Is there a variable for strings in JSON format?
    input_parameters  = string
  }))
  
  default = {
    "1" = {
      name              = "alb-http-to-https-redirection-check"
      description       = "Checks whether HTTP to HTTPS redirection is configured on all HTTP listeners of Application Load Balancers. The rule is NON_COMPLIANT if one or more HTTP listeners of Application Load Balancer do not have HTTP to HTTPS redirection configured."
      owner             = "AWS"
      source_identifier = "ALB_HTTP_TO_HTTPS_REDIRECTION_CHECK"
      input_parameters = <<EOL
      {
        "MaximumExecutionFrequency" : "TwentyFour_Hours",
      }
EOL
  }
 } 
}  

但是如果你想解析这个字符串，你必须使用jsondecode。你不能在变量中使用函数，所以必须稍后再做。

Answer 3

input_parameters = {
    "MaximumExecutionFrequency" : "TwentyFour_Hours",
  }

这必须是字符串而不是对象，因为您将其定义为字符串