aws_codebuild_project: cache config does not stick when cache type set to "NO_CACHE"

[ebarault]

I've been trying to build a aws_codebuild_project module where cache can be enabled/disabled conditionally.

Although not officially documented, cache.type can be set to NO_CACHE, which rather intuitively made me thing i could use this value to indicate cache should not be enabled, just like the artifacts.type = NO_ARTIFACTS config, which it does.

The caveat is that this value does not stick and reapplying the module causes terraform to plan modifications on this value over and over.

Terraform Version

0.11.6

AWS provider version

1.14.0

Affected Resource(s)

aws_codebuild_project

Terraform Configuration Files

resource "aws_codebuild_project" "codebuild_project" {
  # ...
  cache {
    type = "NO_CACHE"
    location = ""
  }
}

Expected Behavior

Once applied, a new terraform apply should not trigger any modification

Actual Behavior

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  ~ aws_codebuild_project.codebuild_project
      cache.0.type: "" => "NO_CACHE"

Reference:

I traced the discussion here
https://github.com/terraform-providers/terraform-provider-aws/pull/2860/files#r160149934

and while i get the rationale that drove to this behavior, I do think the NO_CACHE value should be available to users in a way that would stick, so that modules could conditionally enable caching, just like it's already possible to do with artifacts, using type = NO_ARTIFACTS.

Also, when cache.type is set to NO_CACHE, it should be possible not to define cache.location.

cc: @kaofelix, @bflad

[catsby]

Hey! I agree with your thoughts there, I think NO_CACHE should be valid. Another example usage is a system that was using cache but no longer wants to... with cache being optional and computed, removing the attribute from configuration will not then make the cache become disabled, it just won't be tracked anymore (if I read the code correctly).

[ebarault]

yes, you have a good example too. The discussion in there points this out, if i read correctly too

[catsby]

Unfortunately I'm not sure the Terraform team will be able to address this in the near future, but I've added a comment to #2860 (comment) explaining what we've found here, hopefully someone can pick it up!

From what I can tell, we need to apply a default of NO_CACHE here for cache.

[bflad]

Followup PR submitted: #4134

[bflad]

The fix for this has been merged into master and will release with v1.14.1 of the AWS provider, likely later today.

[bflad]

This has been released in version 1.14.1 of the AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ebarault]

@bflad : just tested this. It works like a charm. Many thanks for fixing this so quickly. 👍

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!