Add support for terragrunt

[gercograndia]

Is your feature request related to a problem? Please describe.

No direct problem.

Describe the solution you'd like

It would be cool if we could use this for managing the terragrunt version as well. We're now using tfenv and tgswitch respectively, both behaving in a slightly different way. Harmonizing this would be great.

[kvendingoldo]

@dvaumoron how do you think, will it be difficult?

[kvendingoldo]

@gercograndia Thanks for issue! I think that we'll try to add Terragrunt support in the near future. Do you have any requirement that we need to keep in mind?

[gercograndia]

Great!!

From a requirements perspective:

• obsiously you need to be able to set the terragrunt version
• it would be great if it tenv could traverse upwards until it finds the right config that specifies the terragrunt file (something that tgswitch doesn't do ATM, but tfenv does).

In general it should behave exactly the same as for terraform and opentofu.

[dvaumoron]

Probably not very difficult with the current design, i will take a look

[dvaumoron]

The harder part will be changing the version detection part (not same kind of behaviour as OpenTofu/Terraform handling), however the last refactoring done have made that easier.

There will also be a difference on the download part, as terragrunt asset are directly binaries, not zip archive.

[dvaumoron]

There will also be subtleties to support tgswitch.toml file, .tgswitchrc file and .terragrunt-version file at the same time.

[gercograndia]

For me the .terragrunt-version would be sufficient. But hey, this is just how we are using it of course.

But also here I would not necessarily aim for feature-partity, but keep the way of working the same as for the rest of tenv.

[dvaumoron]

Done (not tested yet)

[kvendingoldo]

@dvaumoron wow! that was so quick!

[gercograndia]

And quick it was, damn! 😁

[dvaumoron]

Seem to work as expected now, i will update doc

[dvaumoron]

flat files like .opentofu-version or .terragrunt-version and other files like .tgswitch.toml or terragrunt.hcl are not handled in a consistent way. That need a rework.

[kvendingoldo]

@dvaumoron I think that we can move this part of work to another issue.

[kvendingoldo]

@dvaumoron great job!