Added templatestring function similar to templatefile

[sanskruti-shahu]

Objective

The objective of this issue is to address a limitation in Terraform, where the templatefile() function requires a file to be present on disk, thus restricting the dynamism of template usage. The goal is to introduce a new function named templatestring() to enable template usage directly from a string, eliminating the need for a file and enhancing flexibility in generating dynamic templates.

Changes

• Implemented the MakeTemplateStringFunc() function inside string.go, containing the execution logic for the templatestring() function.
• Created a new file, render_template.go, to house the common renderTemplate() function used by both templatestring() and templatefile().
• Added comprehensive tests in string_test.go to validate the implementation of the templatestring() function and renderTemplate() function in render_template_test.go.
• Created templatestring.mdx, a documentation file outlining the usage of the templatestring() function, to be displayed on the opentofu website.
• Updated language-nav-data.json and description.go files to include information about the templatestring() function.
• Updated CHANGELOG.md to reflect the addition of the templatestring() function.

Resolves #301

Target Release

1.7.0

[github-actions]

Reminder for the PR assignee: If this is a user-visible change, please update the changelog as part of the PR.

[Yantrio]

Hi @sanskruti-shahu , thanks for submitting this. I've left some feedback in comments.

[sanskruti-shahu]

@Yantrio I'll work upon the changes that you requested.

[Yantrio]

I've discussed this with the core team, and we believe that in situations where you pass in either

• A sensitive template
• OR any senstive variables

The resultant templated string should be sensitive.

This is in line with other functionality in OpenTofu.

Would you mind implementing it this way please instead of having it error? Thanks!

Please reach out with any questions you have before beginning any other implementations to avoid re-doing some work!

[sanskruti-shahu]

Hey @Yantrio , I've replied to your comments. Could you please check it once? Also, could you review the code changes again to let me know if there are any further changes needed?

[Yantrio]

Hi @sanskruti-shahu , we discussed it in one of the conversations that the sensitive value should be propogated throughout instead of erroring.

Would you mind implementing this please? I do not see this in the current code.

[sanskruti-shahu]

Hey @Yantrio , I've implemented the changes you mentioned. Could you please review them?

[Yantrio]

Apart from the one tiny tiny nitpick, everything is looking good to me. I've requested that @janosdebugs also looks so that I have a second set of eyes on this, just to be safe.

I've been running things locally and i can confirm the sensitive flag is propagated properly as per the tests.

[janosdebugs]

I'm sorry to jump in this late into the PR, but there's a large chunk of copy-pasted code and there's no good reason to maintain two copies of the code. Everything else, including the tests is fine, but this should not be merged as is. Please do not copy-paste this much code.

[sanskruti-shahu]

@janosdebugs , I have implemented the changes you mentioned. Could you please review them?

[cam72cam]

Two small changes @sanskruti-shahu requested, but it's looking good !

[janosdebugs]

Thanks @sanskruti-shahu great job! Tiny nitpick, but I'll approve since these don't change much.