从JSON加载数据到Terraform Map时merge函数报错求助

我尝试将JSON文件中的外部数据加载到Terraform中，合并至appSettings map，但数据加载后为tuple类型，无论进行何种转换都无法得到map，报错信息如下：

Call to function "merge" failed: arguments must be maps or objects, got "tuple".

JSON文件内容 #

[
  {
    "appCode": "value",
    "containerName": "value",
    "databaseName": "value",
    "referer": "bvalue",
    "shortCode": "value",
    "user": "value"
  },
  {
    "appCode": "value",
    "containerName": "value",
    "databaseName": "value",
    "referer": "value",
    "shortCode": "value",
    "user": "value"
  }
]

原Locals代码 #

customerSettings = jsondecode(file("vars/${var.environment}.json"))

customerAppSettingsFromJson = {
  for index, externalCustomer in local.customerSettings :
  externalCustomer => {
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__AppCode"       = "${externalCustomer.appCode}"
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__ContainerName" = "${externalCustomer.containerName}"
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__DatabaseName"  = "${externalCustomer.databaseName}"
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__Referer"       = "${externalCustomer.databaseName}"
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__ShortCode"     = "${externalCustomer.shortCode}"
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__User"          = "${externalCustomer.user}"
  }
}

原Main.tf中appSettings块 #

app_settings = merge({}, var.app_settings, local.customerAppSettingsFromJson)

解决方案 #

问题根源在于你用externalCustomer（一个对象）作为map的key，Terraform不允许用对象作为map键，这会导致customerAppSettingsFromJson被隐式转为tuple而非预期的单层map。

修改Locals代码，生成单层map后再合并：

customerSettings = jsondecode(file("vars/${var.environment}.json"))

customerAppSettingsFromJson = merge([
  for index, externalCustomer in local.customerSettings : {
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__AppCode"       = externalCustomer.appCode
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__ContainerName" = externalCustomer.containerName
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__DatabaseName"  = externalCustomer.databaseName
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__Referer"       = externalCustomer.referer
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__ShortCode"     = externalCustomer.shortCode
    "DynamicCosmosDbSettings__CosmosHostSettings__${index}__User"          = externalCustomer.user
  }
]...)

关键说明 #

1. 通过列表推导式生成多个独立的小map，每个对应一个客户的配置项
2. 使用merge([...])...的展开语法，将列表内的所有map合并为一个单层map
3. 修正了原代码中的笔误：Referer字段的值误写为databaseName，现已改为referer

修改后customerAppSettingsFromJson为标准map，merge函数可正常执行，将其与var.app_settings合并为最终的app_settings。

内容的提问来源于stack exchange，提问作者Stuart.Sklinar