Terraform Azurerm Set Diff Analyzer: Install, Source and Security | FunnelSlayer
FunnelSlayer
Book a call

Terraform Azurerm Set Diff Analyzer

Published by github in awesome-copilot

Review recommended8.9k installs

What this skill does

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.

Add Terraform Azurerm Set Diff Analyzer to your agent

Review the source and files first. When you are ready, copy the prompt instruction or use the CLI command supported by your environment.

Install with a prompt

Paste this into a compatible coding agent:

add this skill "terraform-azurerm-set-diff-analyzer" from https://github.com/github/awesome-copilot

Install with the CLI

Run this command in a controlled environment after reviewing the repository:

npx skills add https://github.com/github/awesome-copilot --skill terraform-azurerm-set-diff-analyzer

Skill instructions

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 plan shows 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: Use python3 instead, or install Python
  • ModuleNotFoundError: Script uses only standard library; ensure Python 3.8+

Detailed Documentation

Files included

  • references/azurerm_set_attributes.json
  • references/azurerm_set_attributes.md
  • scripts/.gitignore
  • scripts/analyze_plan.py
  • scripts/README.md
  • SKILL.md