[Feature Suggestion] Lock on terraform plan

[mechastorm]

Great tool here! Helps solves my team's issue with state conflicts while we figure out our long term solution.

I was wondering if it makes sense to optionally lock at the "terraform plan" stage instead of apply? From what I understood in terragrunt, the locking is only at the "apply" stage (which is great).

The terraform workflow I've been following is

1. terraform plan and output a plan file
2. Get a peer review on the plan and approve it if needed
3. terraform apply against the plan file

So in general, we always ran "terraform apply" against a plan file.

At a previous organisation, we had a bespoke solution where we locked the state file when we begin "plan" stage. That meant that

• no one can change (apply) the infrastructure until that plan has been applied or the user released the lock for that plan.
• other users can still run plan but when they apply their changes on a locked state, they will be prompetd to wait for that other plan to be run and re-run their plan against the new changes
• the user's plan is going to be applied against a state that did not change during the peer review period. There is no chance between the "plan" and "apply" stage that the infrastructure got changed by someone else.

Any thoughts?

[brikis98]

We've had a few requests for long-term locks. Probably the best way to handle it is with a terragrunt lock command. It should be pretty easy to add. Are you interested in submitting a PR?

In the meantime, I'm going to close this issue in favor of #19, since it's more or less a dupe, and I'd like to consolidate the conversation in one place.