terraform: Terraform module for GCP

[elchead]

Context

This PR builds on top of #2503 to add the module for GCP.

Proposed change(s)

• add GCP module

Additional info

• AB#3520
• successful GCP E2E run
• AWS E2E run

Checklist

• Update docs
• Add labels (e.g., for changelog category)
• Is PR title adequate for changelog?
• Link to Milestone

[msanft]

Let's put this on hold until #2503 is merged.

[msanft]

LGTM from a high level. Will give this a more thorough review once the AWS module is merged.

[msanft]

Regarding release pipeline changes, @malt3 should review that.

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[elchead]

Rebased and incorporated feedback. Would you test it also locally on Mac to see if it works as expected for you @msanft?

[msanft]

Rebased and incorporated feedback. Would you test it also locally on Mac to see if it works as expected for you @msanft?

I don't have a MacOS machine set up for development right now unfortunately

[msanft]

TF specific changes LGTM except the comment. Didn't look at release pipeline or Go upgrade. Just ping me once ready for final review

[malt3]

Only reviewed the changes made to the pipeline. They look good to me.
Apologies for the delay in reviewing from my side.

[msanft]

One thing that is broken here, but that will be addressed in #2566:

We cannot default to a latest version when downloading the CLI. This will break for users that have an outdated Terraform module, say of v2.12.0, and try to apply it at a point where v2.13.0 is already released. latest will then point to v2.13.0. If the v2.13.0 CLI is incompatible with the v2.12.0 module, this won't work.

We should rather let the user set the CLI version through a variable in the constellation-cluster module and set it during packaging of the module. I will take care of that in #2566.

[elchead]

One thing that is broken here, but that will be addressed in #2566:

We cannot default to a latest version when downloading the CLI. This will break for users that have an outdated Terraform module, say of v2.12.0, and try to apply it at a point where v2.13.0 is already released. latest will then point to v2.13.0. If the v2.13.0 CLI is incompatible with the v2.12.0 module, this won't work.

We should rather let the user set the CLI version through a variable in the constellation-cluster module and set it during packaging of the module. I will take care of that in #2566.

This is already fixed, Thomas and I decided to inject the version during the release process:

constellation/dev-docs/workflows/release.md

Lines 34 to 35 in cea6204

	Update the `version` inside `terraform/constellation-cluster/install-constellation.sh` to the new release.

We didn't want to expose it as variable to the user, since the user should not need to care about the CLI version and which one is compatible with which TF module.