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首页 > 解决方案 > Terraform - 根据变量创建 cloudwatch 计划表达式 - 预期表达式但找到“*”

interpolation - Terraform - 根据变量创建 cloudwatch 计划表达式 - 预期表达式但找到“*”

问题描述

我正在尝试通过 terraform 创建 AWS Clouwatch 事件规则

variable "schedule_expression" {
  default = "cron(5 * * * ? *)"
  description = "the aws cloudwatch event rule scheule expression that specifies when the scheduler runs. Default is 5 minuts past the hour. for debugging use 'rate(5 minutes)'. See https://docs.aws.amazon.com/AmazonCloudWatch/latest/events/ScheduledEvents.html"
}

我想指定变量而不是 5

variable "AutoStopSchedule" {
   default = "5"
}

variable "schedule_expression" {
  default = "cron(${var.AutoStopSchedule} * * * ? *)"
  description = "the aws cloudwatch event rule scheule expression that specifies when the scheduler runs. Default is 5 minuts past the hour. for debugging use 'rate(5 minutes)'. See https://docs.aws.amazon.com/AmazonCloudWatch/latest/events/ScheduledEvents.html"
}

但得到：

Error: variable "schedule_expression": default may not contain interpolations

主文件

# Cloudwatch event rule
resource "aws_cloudwatch_event_rule" "check-scheduler-event" {
    name = "check-scheduler-event"
    description = "check-scheduler-event"
    schedule_expression = "${var.schedule_expression}"
    depends_on = ["aws_lambda_function.demo_lambda"]
}

我想根据 AutoStopSchedule 变量创建 schedule_expression，怎么做？

尝试以下：

resource "aws_cloudwatch_event_rule" "check-scheduler-event" {
    name = "check-scheduler-event"
    description = "check-scheduler-event"

    #schedule_expression = "cron(15 * * * ? *)"
    schedule_expression = "${var.AutoStopSchedule == "5" ? cron(5 * * * ? *) : cron(15 * * * ? *)}"
    depends_on = ["aws_lambda_function.demo_lambda"]
}

得到expected expression but found "*"

标签： interpolationterraformamazon-cloudwatch

解决方案

你不需要这样做。您需要做的是使用本地代替，例如：

variable "AutoStopSchedule" {
   default = "5"
}


locals{
schedule_expression= "cron(${var.AutoStopSchedule} * * * ? *)"  
}

output "schedule_expression" {
  value = "${local.schedule_expression}"
}

如果你 terraform apply 你得到：

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Outputs:

schedule_expression = cron(5 * * * ? *)

要使用它 ${local.sschedule_expression} 之前有 ${var.schedule_expression} 。

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