AgentSkillsCN

terraform-azurerm-set-diff-analyzer

分析 AzureRM Provider 的 Terraform 计划 JSON 输出，区分虚假阳性差异（Set 类型属性中的仅排序变化）与实际的资源变更。当审查 Azure 资源的 Terraform 计划输出时，尤其是针对 Application Gateway、Load Balancer、Firewall、Front Door、NSG 等具有 Set 类型属性的资源——这些资源因内部排序变化而产生虚假差异时，可使用此技能。

SKILL.md
--- frontmatter
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 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

bash
# 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