Terraform: Is there a way to ignore whitepace changes when generating a plan? - terraform

Question

I wanted to ask if there is a way to ignore whitespace changes when creating a terraform plan.
This question is related to this one, I created a new one because I wanted to give a new example of the issue.
Terraform shows unnecessary changes due to whitespace
For example, when running
terraform plan
I get the following change for a helm provider resource
# helm_release.cert-manager will be updated in-place
~ resource "helm_release" "cert-manager" {
id = "cert-manager"
name = "cert-manager"
~ values = [
- <<-EOT
installCRDs: true
EOT,
+ <<-EOT
installCRDs: true
EOT,
]
# (27 unchanged attributes hidden)
}
I found out that the change was due to line endings. Deployed was CRLF and my local source file had LF as line ending.
Is there an option to ignore whitespaces and/or line ending characters?

Answer 1

It's typically the responsibility of the provider itself to determine whether the prior value and the new value are equivalent despite not being exactly equal, and so making this work automatically would require a change to the provider itself to notice that this argument is defined as being YAML and YAML doesn't ascribe any meaning to the decision between CRLF and just LF. The provider would ideally perform this check itself and thus avoid you needing to worry about it, and I would suggest opening a feature request with the provider developer to see if they would be interested in handling that.
However, if a provider isn't performing that job correctly itself then you can potentially work around it by doing your own normalization of the value using Terraform language features, so that the value passed to the provider is always the same when the meaning is the same.
One straightforward way to achieve that in this case would be to round-trip the value through both yamldecode and yamlencode, thereby normalizing the input to be in the style that yamlencode produces:
values = [yamlencode(yamldecode(var.something))]
If you want to be more surgical about it and only normalize the line endings, you could use replace to remove the CR character from any CRLF pair:
values = [replace(var.something, "\r\n", "\n")]
The above solution assumes that the difference in whitespace is being caused by something in your module, such as if you're storing your Terraform configuration in a misconfigured Git repository that's rewriting LF to CRLF when you clone it on a Windows system. This config-based normalization can undo that sort of transformation so that the provider will always see the value in the same way.
This solution cannot address problems that are caused by the provider itself misbehaving. Unfortunately some providers have bugs where they will silently rewrite the stored values for some arguments during the "refresh" step, regardless of how you wrote it in the configuration. In that case the only recourse is to fix the provider, because that incorrect value is originating inside the provider itself and isn't under the control of the module author.