Terragrunt files

[nilsdebruin]

It could be interesting to include terragrunt.hcl files to the version check. Terragrunt files have the following terraform configuration block (this is an example):

terraform {
source = "git@github.com:terraform-aws-modules/terraform-aws-iam.git//modules/iam-assumable-roles?ref=v2.21.0"
}

Do you know how this could be implemented?

[sgreben]

Hi @nilsdebruin, sorry about the late response - last month was a busy one for me.. I had a look at how Terragrunt does config parsing, and it looks like it actually provides a way to parse just those terraform { source=... } blocks:

• the parse function https://github.com/gruntwork-io/terragrunt/blob/master/config/config_partial.go#L165
• the terragruntTerraformSource struct https://github.com/gruntwork-io/terragrunt/blob/master/config/config_partial.go#L50

I think we should be able to generate ModuleCall structs from these. I gave it a shot in #35 - could you have a look at that? I'm not really familiar with Terragrunt, so someone who actually uses it should definitely review that PR 😄

The meat of it is the file pkg/scan/terragrunt.go, the rest of the diff consists almost entirely of changes to vendored packages.

Here's how its output looks right now:

$ terraform-module-versions -terragrunt=true list examples 

TYPE	NAME	CONSTRAINT	VERSION	SOURCE
registry	consul	~0.7.3		hashicorp/consul/aws
local	local			./local
git	examples/terragrunt.hcl		v2.21.0	git@github.com:terraform-aws-modules/terraform-aws-iam.git//modules/iam-assumable-roles?ref=v2.21.0
git	example_git_ssh_branch		master	git::ssh://git@github.com/keilerkonzept/terraform-module-versions?ref=master
git	example_git_scp	~> 0.12	0.12.0	git::git@github.com:keilerkonzept/terraform-module-versions?ref=0.12.0
git	consul_github_ssh	~0.1.0	0.1.0	git@github.com:hashicorp/terraform-aws-consul?ref=0.1.0
git	consul_github_https_no_ref			github.com/hashicorp/terraform-aws-consul
git	consul_github_https_missing_ref	0.7.3		github.com/hashicorp/terraform-aws-consul
git	consul_github_https	0.8.0	v0.8.0	github.com/hashicorp/terraform-aws-consul?ref=v0.8.0

$ terraform-module-versions -terragrunt=true check examples 

UPDATE?	NAME	CONSTRAINT	VERSION	LATEST MATCHING	LATEST
(Y)	consul	~0.7.3		0.7.11	0.8.4
(Y)	consul_github_https	0.8.0	v0.8.0		v0.8.4
(Y)	consul_github_https_missing_ref	0.7.3		v0.7.3	v0.8.4
(Y)	consul_github_https_no_ref				v0.8.4
Y	consul_github_ssh	~0.1.0	0.1.0	v0.1.2	v0.8.4
(Y)	example_git_scp	~> 0.12	0.12.0		3.0.9
(Y)	example_git_ssh_branch		master		3.0.9
(Y)	examples/terragrunt.hcl		v2.21.0		v3.8.0

[nilsdebruin]

Hi @sgreben, don't worry, thank you for your time and effort! I am really appreciating that you are taking the time to dive into this. As I am not a Go developer, I can only look at it from a functional perspective. I checked out your code, build it, and tested it on a directory with .hcl files. I can validate that it works for this first example, really cool!

I have included a more elaborate example in the examples directory which I have submitted as a PR: #39. This is a more extended example, which is based on the following repo: https://github.com/gruntwork-io/terragrunt-infrastructure-live-example.

When I run the Terragrunt version as follows:

./binaries/osx_x86_64/terraform-module-versions -terragrunt check examples/

I get the following output:

Error: Error in function call

  on examples/terragrunt-example/terraform/terragrunt.hcl line 9, in locals:
   9:   global_vars = read_terragrunt_config(find_in_parent_folders("global.hcl"))

Call to function "find_in_parent_folders" failed: ParentFileNotFound: Could not find a global.hcl in any of the parent folders of examples. Cause: Traversed
all the way to the root..`

ERRO[0000] Encountered error while evaluating locals.   
[terraform-module-versions] read terragrunt config "examples/terragrunt-example/terraform/terragrunt.hcl": examples/terragrunt-example/terraform/terragrunt.hcl:9,40-63: Error in function call; Call to function "find_in_parent_folders" failed: ParentFileNotFound: Could not find a global.hcl in any of the parent folders of examples. Cause: Traversed all the way to the root..

I think this is due to the fact that a terragrunt function is triggerd which is present in the .hcl file, namely:

find_in_parent_folders()

I am unsure if this can turned off and that the file can be scanned / parsed as is. I can imagine that this is quite a complex problem, so I understand if you just leave it at the first iteration (which in my opinion is already very cool!)

[zen]

This would be great feature man. Let me know if I can help somehow, but my Go knowledge is near to zero :(