Terraform：遍历复杂对象列表

Question

我想遍历一个包含两个警报对象的列表，配置如下 - 问题是如何通过循环每个警报指标列表来动态生成 metric_query 块..

   locals{
    prefix = terraform.workspace

    alarm_WithExpression = [
        { "name" : "XXX",
          "expression" : "m1/m2",
          "metrics" : [
            { "id" : "m1", "name" : "YYYY", "statistic" : "Sum", "period" : 21600 },
            { "id" : "m2", "name" : "ZZZZZ" ,"statistic" : "Sum", "period" : 21600 }
          ],
          "threshold" : 0.2,
          "comparison_operator" : "LessThanThreshold",
          "period" : 21600,
          "data_points" : 2,
          "treat_missing_data" : "notBreaching"
        },
        { "name" : "AAAA",
          "expression" : "m1/(m2-m3)",
          "metrics" : [
            { "id" : "m1", "name" : "BBBB", "statistic" : "Sum", "period" : 21600 },
            { "id" : "m2", "name" : "CCCC", "statistic" : "Sum", "period" : 21600 },
            { "id" : "m3", "name" : "DDDD", "statistic" : "Sum", "period" : 21600 }
          ],
          "threshold" : "0.2",
          "comparison_operator" : "LessThanThreshold",
          "period" : 21600,
          "data_points" : 2,
          "treat_missing_data" : "notBreaching"
        }
      ]
    }

这是指标警报声明：

resource "aws_cloudwatch_metric_alarm" "metrics-withExpression_alarm" {
  for_each            = local.prefix == "production" ? {} : {for index,m in local.alarm_WithExpression : index => m}
  alarm_name          = "${local.prefix}-${each.value.name}"
  comparison_operator = each.value.comparison_operator
  evaluation_periods  = each.value.period
  threshold           = each.value.threshold
  treat_missing_data  = each.value.treat_missing_data
  datapoints_to_alarm = each.value.data_points

  metric_query {
    id          = "e"
    expression  = each.value.expression
    return_data = "true"
  }

  # loop inside list of metrics ??
  dynamic "metric_query" {
    for_each = {for index,k in local.alarm_WithExpression.metrics : index => k}
    content {
      id = each.value.id

      metric {
        metric_name = each.value.name
        namespace   = "${local.prefix}-metrics"
        period      = each.value.period
        stat        = each.value.statistic
      }
    }
  }
}

我收到此计划错误：

╷
│ Error: Unsupported attribute
│ 
│   on cloudwatch-alarms.tf line 177, in resource "aws_cloudwatch_metric_alarm" "metrics-withExpression_alarm":
│  177:     for_each = {for index,k in local.alarm_WithExpression.metrics : index => k}
│     ├────────────────
│     │ local.alarm_WithExpression is tuple with 2 elements
│ 
│ This value does not have any attributes.
╵
ERROR: 1

如何遍历每个警报指标列表？

Answer 1

你的问题在于这部分：

local.alarm_WithExpression.metrics

给你一些背景。 local.alarm_WithExpression 是一个列表。该列表没有metrics 属性，因此.metrics 没有给您想要的。

我相信您的目标可以使用他们所谓的splat expressions 来实现，即

local.alarm_WithExpression[*].metrics

用简单的英语可以理解为：

对于local.alarm_withExpression 中的每个对象，获取其metrics 属性

Answer 2

你可以像下面这样实现这个

  dynamic "metric_query" {
    for_each = each.value.metrics
    content {
      id = metrics.value["id"]

      metric {
        metric_name = metrics.value["name"]
        namespace   = "${local.prefix}-metrics"
        period      = metrics.value["period"]
        stat        = metrics.value["statistic"]
      }
    }
  }