Plan: read change representation format

[prelegalwonder]

I've been looking into ways to add the ability to see specific changes for resources to be updated / created and it seems like terraform plan -json output doesn't provide the change representation of before/after.

https://developer.hashicorp.com/terraform/internals/json-format#change-representation

You have to resort to terraform plan -out=tfplan && terraform show -json tfplan > plan.json

Would you be willing to accept a PR to read this json format so support could be added for viewing change details?

[magodo]

@prelegalwonder Thank you to bring this interesting idea! I assume it is meant to be used for:

$ terraform apply -json -auto-approve plan.json | pipeform --plan plan.json

Whilst, it can cause confusion for other cases since pipeform has no knowledge about what command is being run at the other end of the pipe, e.g.

• terraform apply -json -auto-approve | pipeform --plan plan.json
• terraform apply -json -auto-approve plan2.json | pipeform --plan plan.json
• terraform plan -json | pipeform --plan plan.json

On the other hand, given the time that the "plan" stage stays visible is quite short. It seems not too useful to enrich it.

Given the fact that the before/after state can be complicated (multi-lines), what's your idea to render it in the current table structure?

[prelegalwonder]

My use-case was to view the detailed changes in the plan in large change sets prior to applying.

I didn't see a way to represent that cleanly in the current table, so I propose an added a pop-up with scroll-buffer and tried to implement this but ran into the issue where I don't have the detailed change info because its not provided by Terraform.

pipeform-view-changes.mp4

To clarify further, the above scenario is just terraform plan -json | pipeform

Since the data isn't provided in the json plan, accommodations would have to be made to read the different structure that does provide that data from terraform plan -out=tfplan && terraform show -json tfplan

I can assist in providing that functionality but I didn't know if it aligned with your vision for the project :)

[magodo]

@prelegalwonder Your implementation of a new pop up view totally aligns with my assumption! Whilst, providing a out of band input as "plan.json" might cause inconsistency issues in some cases and I'm hesitating to accept this...

I think a better thing here is to try to extend the Terraform machine-readable UI to include that part, as it seems less of a breaking change. Then we can support that in this tool more intuitively.

[prelegalwonder]

I agree 💯 that the better approach is getting these events added to the machine-readable output. Unfortunately thats a long path as I've seen feature requests sit in the TF backlog for years.

I'll give it a shot though and open one for OpenTofu as well and report back here with the issue #'s