terraform 中是否有 AND/OR 条件运算符? [英] Is there a way AND/OR conditional operator in terraform?

问题描述

有没有办法在 Terraform 中使用类似的东西?

Is there a way to use something like this in Terraform?

count = "${var.I_am_true}"&&"${var.I_am_false}"

count = "${var.I_am_true}"&&"${var.I_am_false}"

推荐答案

deniszh 的答案非常接近，但我想我会澄清一下并清理语法.

The answer by deniszh is pretty close, but I thought I'd clarify it a bit and clean up the syntax.

在 Terraform 中，布尔值 true 被转换为 1，布尔值 false 被转换为 0.因此，如果您有两个布尔变量，var.foo 和 var.bar，您可以使用简单的乘法表示 AND:

In Terraform, a boolean true is converted to a 1 and a boolean false is converted to a 0. So if you have two boolean variables, var.foo and var.bar, you can represent AND using simple multiplication:

count = "${var.foo * var.bar}"

在上面的代码中，只有当 var.foo AND var.bar 都为 truecount 才会为 1code>，因为 1 * 1 是 1.在所有其他情况下 (1 * 0, 0 * 1, 0 * 0)，你得到 0.

In the code above, count will be 1 only if var.foo AND var.bar are both true, as 1 * 1 is 1. In all other cases (1 * 0, 0 * 1, 0 * 0), you get 0.

要表示 OR，您可以利用函数 signum(x)，如果你传入的 x 是正数则返回 1，如果 x 为 0 则返回 0，如果 x 则返回 -1是一个负数.考虑到这一点，这里是 OR:

To represent OR, you can take advantage of the function signum(x), which returns 1 if the x you pass in is a positive number, 0 if x is 0, and -1 if x is a negative number. Taking this into account, here is OR:

count = "${signum(var.foo + var.bar)}"

在上面的代码中，如果 var.foo 或 var.bar 为 truecount 将为 1> 和 0 仅当两者都是 false (signum(1 + 1) = 1, signum(1 + 0) = 1, signum(0 + 1) = 1, signum(0 + 0) = 0).

In the code above, count will be 1 if either var.foo OR var.bar is true and 0 only if both are false (signum(1 + 1) = 1, signum(1 + 0) = 1, signum(0 + 1) = 1, signum(0 + 0) = 0).

请注意，要使用上述技术，您必须注意将变量设置为布尔值而不是字符串.你想要这个:

Note that to use the techniques above, you must take care to set the variables to a boolean and NOT a string. You want this:

variable "foo" {
  # Proper boolean usage
  default = true
}

不是这个:

variable "foo" {
  # THIS WILL NOT WORK!
  default = "true"
}

有关如何执行各种 Terraform 条件的更多信息，请查看 Terraform 提示 &技巧:循环、if 语句和陷阱 和 Terraform: Up &正在运行.

For more info on how to do a variety of Terraform conditionals, check out Terraform tips & tricks: loops, if-statements, and gotchas and Terraform: Up & Running.

这篇关于terraform 中是否有 AND/OR 条件运算符?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！