由于 heredoc，Cloudwatch 警报创建失败

编程问答 2022-05-01

问题描述

我正在尝试使用 terraform 创建一个复合 cloudwatch 警报。但不幸的是，我的 terraform 代码因以下错误而中断：

错误：创建 CloudWatch 复合警报时出错 (node-count-office-time-composite-alarm-DP-1474-desert): ValidationError：AlarmRule 不得包含前导或尾随 空白或为空 状态码：400，请求 ID：272b14ae-e6bd-4e65-8bb8-25372d9a5f7c

以下是我的地形代码：

resource "aws_cloudwatch_composite_alarm" "node_count_office_time_alarm" {
  depends_on = [aws_cloudwatch_metric_alarm.node_count,aws_cloudwatch_metric_alarm.office_time]
  alarm_description = "Composite alarm for node count & office time"
  alarm_name        = "node-count-office-time-composite-alarm-${local.postfix}"
  alarm_actions = [var.sns_topic_arn]
  ok_actions    = [var.sns_topic_arn]
alarm_rule =<<-EOF
ALARM(${aws_cloudwatch_metric_alarm.node_count.alarm_name}) AND
ALARM(${aws_cloudwatch_metric_alarm.office_time.alarm_name})
EOF
}

我检查了很多次，我的 alarm_rule 中没有前导或尾随空格。 AND 运算符后仅换行。我正在使用 terraform 0.15.3 版本。任何人都面临类似的问题，我该如何解决这个问题？谢谢

解决方法

我没有找到如何使 heredoc 工作的解决方案。但是我暂时使用直接字符串表达式而不是heredoc块来修复它。以下是字符串表达式：

alarm_rule        = "ALARM(${aws_cloudwatch_metric_alarm.node_count.alarm_name}) AND ALARM(${aws_cloudwatch_metric_alarm.office_time.alarm_name})"

如果其他人面临同样的问题，我希望它对他们有用。谢谢

,

截至 2021 年撰写本文时，Terraform 说明 https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/cloudwatch_composite_alarm 不准确。

alarm_rule 接受单个字符串参数，必须处理 EOF/heredoc 以创建文字字符串：

locals {
  alarm_rule_with_newlines = <<-EOF
    ALARM(${aws_cloudwatch_metric_alarm.alpha.alarm_name}) OR
    ALARM(${aws_cloudwatch_metric_alarm.bravo.alarm_name})
  EOF
}

[...]

alarm_rule = trimspace(replace(local.alarm_rule_with_newlines,"/\n+/"," "))
amazon-cloudwatchcloudwatch-alarmsheredocheredocterraform