Support resolving terraform version from config

[dkirrane]

I'm looking for a feature similar to actions/setup-go@v5 https://github.com/actions/setup-go?tab=readme-ov-file#getting-go-version-from-the-gomod-file

If we could pass a terraform-version-file that takes a path to a .tf file containing the terraform block with required_version e.g.

versions.tf

terraform {
  required_version = "1.3.6"
}

action

uses: hashicorp/setup-terraform@v3
with:
    terraform-version-file: 'path/to/versions.tf'

Or better still just automatically find the .tf file with required_version config

[vsamofal]

I do use this action to get a version dflook/terraform-version@v1 (cool to have it built in, but at least some workaround)

[guitarrapc]

FYI, I've written bash 1 liner to retrieve required_version and use it with setup-terraform. If you are using simple version string, "= 1.8.4" and ~> 1.8.0, it works fine. Complex versioning is out of scope.

https://gist.github.com/guitarrapc/371018c583e409990daba76df7f062f5

[antm-pp]

I don't think this does work as the true terraform required_version block is not semver (which setup_terraform uses)

required_version = "~> 1.8"

In terraform init that's read as only allow changes to rightmost value, so in current builds 1.9.3 etc would be valid. Things like tfswitch read it the same way as terraform and pull the correct version.

In setup_terraform this gets read as semver allow any patch value not exceeding 1.8 eg 1.8.5 and not 1.9.x. Therefore you will get inconsistent results.

Not sure if that's what was meant about the 'complex versioning' limitation in the above comment. But really these things should all work consistently.