feat: Add terraform_validate support to init modules and providers if needed

[jgrumboe]

Put an x into the box if that apply:

• This PR introduces breaking change.
• This PR fixes a bug.
• This PR adds new functionality.
• This PR enhances existing functionality.

Description of your changes

This PR adds logic to terraform_validate to detect if module initialization is needed and run it. It's also possible now to force an initialization and/or provider upgrade by just adding the documented init-args to the hook call.

The new logic works as follows:
terraform providers is called on every run and used to detect if all needed modules are initialized correctly. If it succeeds it will pass -get=false to the terraform init call, which prevents modules to be re-downloaded. On the other hand, if terraform providers fails, this means modules or providers are not initialized and -get=truewill be passed to terraform init - a full initialization will happen.

Since terraform init will be called every time, the already existing --init-args feature will give us to additional benefits:

• --init-args=-get=true will result in a forced initialization on every run
• --init-args=-upgrade will allow to upgrade providers in addition to the modules if needed

Fixes #224

How has this code been tested

1. You need to have terraform code which references modules and providers.
2. Delete .terraform folder if present
3. Change a module version in your code to some other existing version and stage the commit
4. run pre-commit run terraform_validate and you see that it will initialize the .terraform folder newly and validate your code.
5. Every re-run of pre-commit run terraform_validate will be faster, as long as no module version changes happen
6. Again change a module version in your code to some other existing version and stage the commit
7. run pre-commit run terraform_validate and you see that it will reinitialize for the new module

Repeat the above steps with changing provider version and setting the --init-args=-upgrade argument. You will notice that only providers or both are initialized if needed.

[antonbabenko]

Looks pretty good. Let's see what @yermulnik or @MaxymVlasov have to say after they test it locally.

[yermulnik]

Nice catch on using terraform providers to validate modules installation.
Code looks good to me.

[MaxymVlasov]

You should return that check and add check that checks that any --init-args provided.

Because, time execution increased up to 80-90% for:

repos:
- repo: [email protected]:jgrumboe/pre-commit-terraform.git
  rev: '4086982'
  hooks:
  - id: terraform_validate

compare with:

repos:
- repo: https://github.com/antonbabenko/pre-commit-terraform
  rev: v1.62.0
  hooks:
 - id: terraform_validate

[MaxymVlasov]

No need to run terraform init each time if it is not specified by arguments.
Or need to explicitly provide force-init: true etc. for that.

For now, it just looks like no needed speed violation.

[jgrumboe]

Thanks for your input.
I will try to come up with a better solution, which is fast as now when no modules/providers version changes were made in the code and still eliminates the need for manual deletion of the .terraform folder in case modules/providers version changes are made.

[MaxymVlasov]

Hi @jgrumboe
Any updates? Do you need any help?

[jgrumboe]

Hi @MaxymVlasov
Sorry, this one slipped out of my mind. I will have a look next week.
Thanks for the reminder.

[MaxymVlasov]

Close as too outdated. Simpler to create a new branch with specified changes than try to resolve conflicts