Terraform 基础知识 - 变量
变量 (var)
为了使代码更DRY化和可配置化,terraform允许用户定义输入变量。
输入变量、输出变量
变量语法
varible "NAME" {
[CONFIG ...]
}
变量声明包含3个参数:
description
描述参数用来说明如何使用这个变量
default
有多种方法可以为变量赋值,包含
命令行(-var)
terraform plan -var "server_port = 8080"
文件(-var-file)
环境变量(TF_VAR_<variable_name>)
export TF_VAR_server_port = 8080
type
允许对用户输入的变量类型进行强制约束;
包含string、number、bool、list、map、set、object、tuple、any(默认约束类型为any)
string
字符串
variable "map_example" {
description = "an example of a map in terrform"
type = map(string)
default = {
key1 = "value1"
key2 = "value2"
key3 = "value3"
}
}
number
数字
variable "number_example" {
description = "an example of a number variable in terraform"
type = number
default =2
}
list
列表为字符串
variable "list_example" {
description = "an example of a list in terraform"
type = list
default = ["a","b","c"]
}
列表为数字
variable "list_number_example" {
description = "an example of a number list in terraform"
type = list(number)
default = [1,2,3]
}
更加复杂的对象和元祖结构类型
variable "object_example" {
description = "an example of a structural type in terraform"
type = object({
name = string
age = number
tags = list(string)
enabled = bool
})
default = {
name = "value"
age = 18
tags = ["a","b","c"]
enabled = true
}
}
注意:如果变量设置的与类型约束不匹配的值,terraform会报错
name为字符串
age为数字
tags为字符串列表
enabled为布尔值
例如在某个配置文件需要配置一个端口的变量
variable "server_port" {
description = "The port the server will use for HTTP requests"
type = number
}
如果没有输入默认的变量,执行plan或者apply会显示下面提示
# terraform plan
var.server_port
The port the server will use for HTTP requests
Enter a value:
如果不想每次处理交互式提示,可以通过命令的形式为变量提供初始化
# export TF_VAR_server_port=8080
# terraform plan
直接设定一个默认值
variable "server_port" {
description = "The port the server will use for HTTP requests"
type = number
default = 8080
}
变量引用
语法如下
var.<VARIABLE_NAME>
具体配置
resource "aws_security_group" "instance" {
name = "terraform-example-instance"
ingress {
cidr_blocks = [ "0.0.0.0/0" ]
description = "mono"
from_port = var.server_port
protocol = "TCP"
to_port = var.server_port
}
}
输出变量
语法
output "<NAME>" {
value = <VALUE>
[CONFIG]
}
output "public_ip" {
value = aws_instance.example.public_ip
description = "public ip"
}
注意 你要执行apply执行才会显示IP,如果执行plan会显示下面信息
Changes to Outputs:
+ public_ip = (known after apply)
正确output输入
Apply complete! Resources: 2 added, 0 changed, 0 destroyed.
Outputs:
public_ip = "18.183.127.183"
可以将新创建的服务器的IP地址作为变量输出在命令行上,而不必跟以前一样,登录AWS控制台查看IP地址
或者
# terraform output public_ip
18.183.127.183