Implement a DevOps-specific custom ruleset plugin

Summary

We want to implement a custom TFLint ruleset to enforce DevOps-specific Terraform linting standards that are not covered by existing community rulesets such as tflint-ruleset-terraform or tflint-ruleset-google.

Scope

This issue tracks the creation of a custom TFLint plugin, integration into our Docker infrastructure, and adoption in the standard Terraform CI pipeline.

Details

• Custom Ruleset Plugin
  We'll create a new TFLint plugin dedicated to checks relevant to our DevOps practices.

• Initial Rule
  The first rule to be included will enforce version constraint formatting:

  • Root modules must use the ~> major.minor format.
  • Reusable/shared modules must use the >= version format.

• Docker Integration
  The custom plugin will be included in a new Docker image built and maintained in our dockerimages repository.

• CI Pipeline Update
  The tflint job in our standard Terraform pipeline will be updated to use this new Docker image, ensuring the new rule is automatically enforced during CI.

Acceptance Criteria

• A new TFLint plugin project exists with the initial rule implemented and tested.
• The plugin is packaged into a custom Docker image in the dockerimages repo.
• CI templates are modified to use the new image.
• Repository pipelines are updated to use the CI templates.
• Documentation is added for how to maintain and extend the ruleset.