terraform-azurerm-set-diff-analyzer
github/awesome-copilot
Spot real Terraform AzureRM changes by filtering out noisy Set-attribute reorder diffs.
What is terraform-azurerm-set-diff-analyzer?
This skill analyzes Terraform plan JSON output for AzureRM Provider resources to identify false-positive diffs caused by Set-type attribute reordering, separating them from genuine resource changes. Use it when terraform plan shows excessive 'changed' elements for resources like Application Gateway, Load Balancer, Firewall, Front Door, or NSG after only a small actual modification.
- Parses Terraform plan JSON output for AzureRM resources
- Identifies Set-type attributes prone to order-based false-positive diffs
- Distinguishes order-only changes from actual resource changes
- Provides exit codes and output formats suitable for CI/CD integration
How to install terraform-azurerm-set-diff-analyzer
npx skills add https://github.com/github/awesome-copilot --skill terraform-azurerm-set-diff-analyzer- Python 3.8+ installed
- Terraform CLI to generate plan and plan JSON output
How to use terraform-azurerm-set-diff-analyzer
- 1.Generate a Terraform plan and save it: terraform plan -out=plan.tfplan
- 2.Convert the plan to JSON: terraform show -json plan.tfplan > plan.json
- 3.Run the analyzer: python scripts/analyze_plan.py plan.json
- 4.Review the output to see which diffs are false-positive (order-only) vs actual changes
- 5.Optionally integrate the script into CI/CD to auto-filter false-positive diffs
Use cases
- Reviewing a large terraform plan diff to confirm only one element was actually added/removed from a Set attribute
- Investigating why an Application Gateway or Load Balancer shows all elements as changed after a minor config tweak
- Filtering false-positive diffs automatically in a CI/CD pipeline before requiring manual approval
- Auditing NSG, Firewall, or Front Door plan output for genuine security or routing changes vs ordering noise
- Terraform/DevOps engineers managing Azure infrastructure
- Platform teams reviewing pull requests with terraform plan output
- CI/CD pipeline maintainers wanting automated diff filtering for AzureRM resources
terraform-azurerm-set-diff-analyzer FAQ
Terraform's Set type compares elements by position rather than by key, so adding or removing an element shifts positions and makes all elements appear as 'changed' even though they aren't.
No. It only analyzes the JSON output of terraform plan to distinguish false-positive ordering diffs from real changes; it does not apply or modify anything.
Resources with Set-type attributes such as Application Gateway, Load Balancer, Firewall, Front Door, and NSG, where internal ordering changes cause spurious diffs.
Python 3.8+ (standard library only, no extra modules needed).
Full instructions (SKILL.md)
Source of truth, from github/awesome-copilot.
name: terraform-azurerm-set-diff-analyzer description: Analyze Terraform plan JSON output for AzureRM Provider to distinguish between false-positive diffs (order-only changes in Set-type attributes) and actual resource changes. Use when reviewing terraform plan output for Azure resources like Application Gateway, Load Balancer, Firewall, Front Door, NSG, and other resources with Set-type attributes that cause spurious diffs due to internal ordering changes. license: MIT
Terraform AzureRM Set Diff Analyzer
A skill to identify "false-positive diffs" in Terraform plans caused by AzureRM Provider's Set-type attributes and distinguish them from actual changes.
When to Use
terraform planshows many changes, but you only added/removed a single element- Application Gateway, Load Balancer, NSG, etc. show "all elements changed"
- You want to automatically filter false-positive diffs in CI/CD
Background
Terraform's Set type compares by position rather than by key, so when adding or removing elements, all elements appear as "changed". This is a general Terraform issue, but it's particularly noticeable with AzureRM resources that heavily use Set-type attributes like Application Gateway, Load Balancer, and NSG.
These "false-positive diffs" don't actually affect the resources, but they make reviewing terraform plan output difficult.
Prerequisites
- Python 3.8+
If Python is unavailable, install via your package manager (e.g., apt install python3, brew install python3) or from python.org.
Basic Usage
# 1. Generate plan JSON output
terraform plan -out=plan.tfplan
terraform show -json plan.tfplan > plan.json
# 2. Analyze
python scripts/analyze_plan.py plan.json
Troubleshooting
python: command not found: Usepython3instead, or install PythonModuleNotFoundError: Script uses only standard library; ensure Python 3.8+
Detailed Documentation
- scripts/README.md - All options, output formats, exit codes, CI/CD examples
- references/azurerm_set_attributes.md - Supported resources and attributes
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