How to template file in cdktf

Terraform CDK for Terraform
1

Hello,

How would I go about templating a file using cdktf? I’m working through doing AWS fargate deployments and I’d like to template my container definitions.

2

You can use Fn.templatefile(path, vars) for this, it synthesises to the templatefile function.

3

Is there a working example I could look at?

4

Hi @kingemn :wave:

Which language are you using? If those container definitions are e.g. a string containing JSON you could also construct that JSON object in your language and pass that to Fn.jsonencode.
In TypeScript that could look something like this:

import * as aws from "./.gen/providers/aws";
new aws.ecs.EcsTaskDefinition(this, "service", {
  containerDefinitions: Fn.jsonencode([{ name: "app", image: "nginx", ... }])
});

You can also use variables and refer attributes of other resources instead of "nginx" for example. You don’t need a template when using CDKTF the way you if you were writing HCL.

So the answer depends a bit on your exact templating needs :slightly_smiling_face:

5

I was able to solve it, so I will leave it as a memo.
The second argument can specify a variable for interpolation.

import { Fn } from 'cdktf'

const tmpFile = Fn.templatefile(join(__dirname, './workflows/test.yaml'), {})