Terraform 中如何使用数据源? [英] How are data sources used in Terraform?

问题描述

Terraform 数据源文档告诉我什么是数据源，但我不太明白.有人可以给我一个数据源的用例吗?它和使用变量配置有什么区别?

The Terraform Data Sources documentation tells me what a data source is, but I do not quite understand it. Can somebody give me a use case of data source? What is the difference between it and configuring something using variables?

推荐答案

可以使用数据源的原因有很多；但他们的目标是做某事，然后给你数据.

Data sources can be used for a number of reasons; but their goal is to do something and then give you data.

让我们以他们的文档为例:

# Find the latest available AMI that is tagged with Component = web
data "aws_ami" "web" {
  filter {
    name   = "state"
    values = ["available"]
  }

  filter {
    name   = "tag:Component"
    values = ["web"]
  }

  most_recent = true
}

这使用 aws_ami 数据源 - 这是不同的比资源！相反，它只会为您提供信息，而不是创建任何东西.此示例将特别调用 describe-images AWS API 调用，传入一些指定的 --filter 选项，并返回一个您可以获取信息的对象来自 - 看看这些 属性！

This uses the aws_ami data source - this is different than a resource! It will instead just give you information, and not create anything. This example in particular will call out to the describe-images AWS API call, pass in a few --filter options as specified, and return an object that you can get information from - take a look at these attributes!

• 姓名
• owner_id
• 说明
• image_id

... 名单还在继续.如果我是这样的话，这真的很有用，比方说 - 总是想提取与某些标签匹配的最新 AMI，并保持启动配置是最新的.我可以使用此数据提供程序，而不必总是更新变量或对 ID 进行硬编码.

... The list goes on. This is really useful if I were, let's say - always wanting to pull the latest AMI matching some tags, and keep a launch configuration up to date with it. I could use this data provider rather than always have to update a variable or hard-code the ID.

数据源也可以用于其他原因；我最喜欢的一个是 模板提供程序.

Data source can be used for other reasons as well; one of my favorites is the template provider.

祝你好运！

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