Taking the output of templatefile() as in input to be interpolated

Terraform
1

Hi,

I have a question about whether its possible to build a terraform data type (specifically a ‘set of objects’) using the rendered output of the templatefile() function …and then use this output as an input value to be passed into a module? …I cant seem to get it to work

So to explain , I have a pipelines.tmpl file that looks like this

pipelines_rendered = [
%{~ for p in pipelines  ~}
  {
    name                  = "${p.name}"
    project               = "blah"
    version               = "${p.ver}"
    branch                =  "something"
    description           =  "blah"
    ...
    ...
  },
%{~ endfor ~}
]

This is fed from local.pipelines that looks like this

locals {
  pipelines = [
    { name = "foo", ver = "1" },
    { name = "bar", ver = "1" },
	...
  ]
}

The final rendered output of this templatefile() forms, what looks exactly like, the ‘set of objects’ structure that I need . I now want to feed this resultant ‘set of objects’ created by the template into a module as an input (to be interpolated) … Specifically, as the value of a variable called ‘pipelines_in’ (this variable is declared as type ‘set of objects’ in the target module)

So as you can see below, when calling the module, I am invoking the templatefile() function to return the rendered output (set of objects) … to form the value of the 'pipelines_in` variable

module "build_pipelines" {
  source        = "somewhere:/mymodule"
  pipelines_in     = templatefile("${path.module}/pipelines.tmpl", { pipelines = local.pipelines })
}

But whatever I try here, I seem to get the same error when running a plan

│ Error: Invalid value for input variable
│ 
│ The given value is not suitable for module.mymodule.var.pipelines
│ declared at
│ .terraform/modules/mymodule/terraform/variables.tf:35,1-21: set of
│ object required.

Is there is an issue when taking the output of templatefile() as in input to be interpolated ?

Is there another way i should be doing this (the brief is to remove the need for developers to have to build a full ‘set of objects’ , but instead just add a few variables and let the template build the full set of objects

2

Maybe a dumb question, but should the pipelines_rendered = part be in the template? Could the variable being getting passed in as foo = {...} vs as {}? Also maybe could be issues with newlines or spacing?

If the input is a local var vs. some kind of external source, would it work to use a map comprehension vs a template file?