Specify a module version when using terraform init -from-module and a private registry module source

[bminahan73]

Terraform Version

1.9.8

Use Cases

I want to fully automate creation of new terraform configurations, starting from a module in a private module registry, saving developers time with initial project setup in a scaled org.

Attempted Solutions

-from-module seemed like the best way to do this, as I could simply run terraform init -from-module=<my module> in a new git repo as a starting point for a new configuration. I was also evaluating terragrunt scaffold for this automation use case, but would like to stick with Terraform only if possible.

-from-module works great for my modules in a private module registry (gitlab), but ONLY for the latest version of the module. If I wanted to deploy a previous module version, I don't think there is a way to do that.

Proposal

terraform init -from-module="gitlab.com/foo/my-module/local"

works, but pulls only latest version of the module.

Add a version specification:

terraform init -from-module="gitlab.com/foo/my-module/local?version=1.0.1"

Currently this gives an Invalid module source address error. Instead it should pull version 1.0.1 of the module.

References

terragrunt scaffold

[crw]

Thanks for this feature request! If you are viewing this issue and would like to indicate your interest, please use the 👍 reaction on the issue description to upvote this issue. We also welcome additional use case descriptions. Thanks again!

[dbanck]

Hi @bminahan73!

The ?ref query parameter should allow you to specify a git commit or tag. The argument to -from-module is similar to a regular module source attribute.

For example you can run this to install a specific commit:

terraform init --from-module='git@github.com:hashicorp-education/terraform-aws-redis-ec2.git?ref=308bd13baf8c42114f924fff699378b8a77002c3

I hope this helps!

[bminahan73]

Hi @dbanck, thank you for looking into this! the ref is for git module sources. I am wanting to pull from a private terraform module registry.

[bminahan73]

or even the public module registry. For example, try to pull the iam module here, but NOT the latest version: https://registry.terraform.io/modules/terraform-aws-modules/iam/aws/latest

This is the result:

$ terraform init -from-module=terraform-aws-modules/iam/aws?version=6.2.0
Copying configuration from "terraform-aws-modules/iam/aws?version=6.2.0"...
╷
│ Error: Invalid module source address
│
│ Failed to parse module source address: Terraform cannot detect a supported external module source type for
│ terraform-aws-modules/iam/aws?version=6.2.0

where I would want something like this, but for the 6.2.0 (older) version of the module:

$ terraform init -from-module=terraform-aws-modules/iam/aws
Copying configuration from "terraform-aws-modules/iam/aws"...

Terraform initialized in an empty directory!

The directory has no Terraform configuration files. You may begin working
with Terraform immediately by creating Terraform configuration files.

just to be sure ref did not work:

$ terraform init -from-module=terraform-aws-modules/iam/aws?ref=6.2.0
Copying configuration from "terraform-aws-modules/iam/aws?ref=6.2.0"...
╷
│ Error: Invalid module source address
│
│ Failed to parse module source address: Terraform cannot detect a supported external module source type for
│ terraform-aws-modules/iam/aws?ref=6.2.0
╵

[dbanck]

Ah, sorry. I assumed that GitLab would allow modules to be fetched via Git.

Currently, it is not possible to specify a version for registry modules (public or private)

[bminahan73]

fetching via git is possible, but requires extra permissions granted to consumers so is not optimal. Plus you don't get the benefits of module version constraints that come from pulling from a module registry (ex: version ~> 5)