Terraform是否支持条件属性?我只想根据变量的值使用属性。
示例:
resource "aws_ebs_volume" "my_volume" {
availability_zone = "xyz"
size = 30
if ${var.staging_mode} == true:
snapshot_id = "a_specific_snapshot_id"
endif
}
我正在寻找上面包含属性if
的{{1}}语句。 Terraform是否基于变量的值支持这种属性包含。
答案 0 :(得分:4)
我不知道这样的功能,但是,如果您的案例不太复杂,则可以对此建模。由于布尔值exec sp_executesql N'SET NOCOUNT ON;
INSERT INTO [Items] ([Name])
VALUES (@p0);
SELECT [ID], [Code]
FROM [Items]
WHERE @@ROWCOUNT = 1 AND [ID] = scope_identity();
',N'@p0 nvarchar(50)',@p0=N'Item1'
和Code
被认为是true
和false
,因此您可以在计数内使用它们。所以你可以使用
1
由于具有0
属性,因此只能创建两种资源之一。
您必须使用provider "null" {}
resource "null_resource" "test1" {
count= ${var.condition ? 1 : 0}
}
resource "null_resource" "test2" {
count = ${var.condition ? 0 : 1}
}
output "out" {
value = "${var.condition ? join(",",null_resource.test1.*.id) : join(",",null_resource.test2.*.id) }"
}
作为值,因为这似乎可以很好地处理两个值之一的不存在。
感谢ydaetskcor在their answer中指出了变量处理方面的改进。
答案 1 :(得分:3)
Terraform 0.12(尚未发布)还将带来support for HCL2,它使您可以将可空参数用于类似这样的事情:
resource "aws_ebs_volume" "my_volume" {
availability_zone = "xyz"
size = 30
snapshot_id = "staging_mode ? a_specific_snapshot_id : null"
}
可空参数包含在this 0.12 preview guide中。
就目前而言,{0.1}之前的Markus的answer可能是您最好的选择,尽管我会更明确地使用count
这样的东西:
resource "aws_ebs_volume" "staging_volume" {
count=${var.staging_mode ? 1 : 0}
availability_zone = "xyz"
size = 30
snapshot_id = "a_specific_snapshot_id"
}
resource "aws_ebs_volume" "non_staging_volume" {
count=${var.staging_mode ? 0 : 1}
availability_zone = "xyz"
size = 30
}
请注意,资源名称必须唯一,否则Terraform将抱怨。然后,如果您需要引用EBS卷(例如使用pre 0.12 the ternary expression is not lazy中的aws_volume_attachment
),则会引起问题,因此这样的操作不起作用:
resource "aws_volume_attachment" "ebs_att" {
device_name = "/dev/sdh"
volume_id = "${var.staging_mode ? aws_ebs_volume.staging_volume.id : aws_ebs_volume.non_staging_volume.id}"
instance_id = "${aws_instance.web.id}"
}
因为它将尝试评估三进制的两边,其中在任一点上只有一个有效。在Terraform 0.12中,情况将不再如此,但是显然,您可以使用可为空的参数来更轻松地解决它。
答案 2 :(得分:2)
现在已发布Terraform v0.12和相应的HCL2,只需将默认变量值设置为“ null”就可以实现。在Terraform网站上查看以下示例:
variable "override_private_ip" {
type = string
default = null
}
resource "aws_instance" "example" {
# ... (other aws_instance arguments) ...
private_ip = var.override_private_ip
}
更多信息在这里:
https://www.hashicorp.com/blog/terraform-0-12-conditional-operator-improvements
答案 3 :(得分:0)
仅是帮助,一个更复杂的示例:
data "aws_subnet" "private_subnet" {
count = var.sk_count
vpc_id = data.aws_vpc.vpc.id
availability_zone = element(sort(data.aws_availability_zones.available.names), count.index)
tags = {
Name = var.old_cluster_fqdn != "" ? "${var.old_cluster_fqdn}-prv-subnet-${count.index}" : "${var.cluster_fqdn}-prv-subnet-${count.index}"
}
}
答案 4 :(得分:0)
Terraform 0.15 有一项新的实验性功能:defaults
可与 optional
配合使用。
defaults 函数是一个专门用于输入变量的函数,输入变量的类型约束是对象类型或包含可选属性的对象类型集合。
来自文档:
terraform {
# Optional attributes and the defaults function are
# both experimental, so we must opt in to the experiment.
experiments = [module_variable_optional_attrs]
}
variable "storage" {
type = object({
name = string
enabled = optional(bool)
website = object({
index_document = optional(string)
error_document = optional(string)
})
documents = map(
object({
source_file = string
content_type = optional(string)
})
)
})
}
locals {
storage = defaults(var.storage, {
# If "enabled" isn't set then it will default
# to true.
enabled = true
# The "website" attribute is required, but
# it's here to provide defaults for the
# optional attributes inside.
website = {
index_document = "index.html"
error_document = "error.html"
}
# The "documents" attribute has a map type,
# so the default value represents defaults
# to be applied to all of the elements in
# the map, not for the map itself. Therefore
# it's a single object matching the map
# element type, not a map itself.
documents = {
# If _any_ of the map elements omit
# content_type then this default will be
# used instead.
content_type = "application/octet-stream"
}
})
}