Terraform Style Guide

作者 hashicorpf706481af9b8無授權條款890 個星標收錄於 2026年10月8日更新於 2026年10月8日儲存庫3 天前更新

Generate Terraform HCL code following HashiCorp's official style conventions and best practices. Use when writing, reviewing, or generating Terraform configurations.

僅含說明DevOps & Cloud

AI 產生的概覽

依照 HashiCorp 官方風格慣例與最佳實務產生並審查 Terraform HCL 程式碼。

功能: 提供撰寫與審查 Terraform 設定的結構化指南，涵蓋檔案組織、格式、命名慣例、變數、輸出、動態資源建立、版本固定、供應商設定與版本控制。內容包含程式碼範例與程式碼審查清單。它也指向另一份安全性文件，用於加密與敏感資料的指引。
適用情境: 適用於撰寫、審查或產生 Terraform 設定，並希望遵循 HashiCorp 官方風格慣例的情況。也適合依標準審查清單檢查現有設定。
執行需求: 不需要指令碼或套件，僅為說明性內容。若要執行其建議的驗證步驟，需安裝 Terraform CLI，並可選用 tflint、checkov 或 tfsec。

Terraform Style Guide

Generate and maintain Terraform code following HashiCorp's official style conventions and best practices.

Reference: HashiCorp Terraform Style Guide

Code Generation Strategy

When generating Terraform code:

Start with provider configuration and version constraints
Create data sources before dependent resources
Build resources in dependency order
Add outputs for key resource attributes
Use variables for all configurable values

File Organization

File	Purpose
`terraform.tf`	Terraform and provider version requirements
`providers.tf`	Provider configurations
`main.tf`	Primary resources and data sources
`variables.tf`	Input variable declarations (alphabetical)
`outputs.tf`	Output value declarations (alphabetical)
`locals.tf`	Local value declarations

Example Structure

hcl

# terraform.tfterraform {  required_version = ">= 1.14"
  required_providers {    aws = {      source  = "hashicorp/aws"      version = "~> 6.0"    }  }}
# variables.tfvariable "environment" {  description = "Target deployment environment"  type        = string
  validation {    condition     = contains(["dev", "staging", "prod"], var.environment)    error_message = "Environment must be dev, staging, or prod."  }}
# locals.tflocals {  common_tags = {    Environment = var.environment    ManagedBy   = "Terraform"  }}
# main.tfresource "aws_vpc" "main" {  cidr_block           = var.vpc_cidr  enable_dns_hostnames = true
  tags = merge(local.common_tags, {    Name = "${var.project_name}-${var.environment}-vpc"  })}
# outputs.tfoutput "vpc_id" {  description = "ID of the created VPC"  value       = aws_vpc.main.id}

# terraform.tfterraform {  required_version = ">= 1.14"
  required_providers {    aws = {      source  = "hashicorp/aws"      version = "~> 6.0"    }  }}
# variables.tfvariable "environment" {  description = "Target deployment environment"  type        = string
  validation {    condition     = contains(["dev", "staging", "prod"], var.environment)    error_message = "Environment must be dev, staging, or prod."  }}
# locals.tflocals {  common_tags = {    Environment = var.environment    ManagedBy   = "Terraform"  }}
# main.tfresource "aws_vpc" "main" {  cidr_block           = var.vpc_cidr  enable_dns_hostnames = true
  tags = merge(local.common_tags, {    Name = "${var.project_name}-${var.environment}-vpc"  })}
# outputs.tfoutput "vpc_id" {  description = "ID of the created VPC"  value       = aws_vpc.main.id}

Code Formatting

Indentation and Alignment

Use two spaces per nesting level (no tabs)
Align equals signs for consecutive arguments

hcl

resource "aws_instance" "web" {  ami           = "ami-0c55b159cbfafe1f0"  instance_type = "t2.micro"  subnet_id     = "subnet-12345678"
  tags = {    Name        = "web-server"    Environment = "production"  }}

resource "aws_instance" "web" {  ami           = "ami-0c55b159cbfafe1f0"  instance_type = "t2.micro"  subnet_id     = "subnet-12345678"
  tags = {    Name        = "web-server"    Environment = "production"  }}

Block Organization

Arguments precede blocks, with meta-arguments first:

hcl

resource "aws_instance" "example" {  # Meta-arguments  count = 3
  # Arguments  ami           = "ami-0c55b159cbfafe1f0"  instance_type = "t2.micro"
  # Blocks  root_block_device {    volume_size = 20  }
  # Lifecycle last  lifecycle {    create_before_destroy = true  }}

resource "aws_instance" "example" {  # Meta-arguments  count = 3
  # Arguments  ami           = "ami-0c55b159cbfafe1f0"  instance_type = "t2.micro"
  # Blocks  root_block_device {    volume_size = 20  }
  # Lifecycle last  lifecycle {    create_before_destroy = true  }}

Naming Conventions

Use lowercase with underscores for all names
Use descriptive nouns excluding the resource type
Be specific and meaningful
Resource names must be singular, not plural
Default to main for resources where a specific descriptive name is redundant or unavailable, provided only one instance exists

hcl

# Badresource "aws_instance" "webAPI-aws-instance" {}resource "aws_instance" "web_apis" {}variable "name" {}
# Goodresource "aws_instance" "web_api" {}resource "aws_vpc" "main" {}variable "application_name" {}

# Badresource "aws_instance" "webAPI-aws-instance" {}resource "aws_instance" "web_apis" {}variable "name" {}
# Goodresource "aws_instance" "web_api" {}resource "aws_vpc" "main" {}variable "application_name" {}

Variables

Every variable must include type and description:

hcl

variable "instance_type" {  description = "EC2 instance type for the web server"  type        = string  default     = "t2.micro"
  validation {    condition     = contains(["t2.micro", "t2.small", "t2.medium"], var.instance_type)    error_message = "Instance type must be t2.micro, t2.small, or t2.medium."  }}
variable "database_password" {  description = "Password for the database admin user"  type        = string  sensitive   = true}

variable "instance_type" {  description = "EC2 instance type for the web server"  type        = string  default     = "t2.micro"
  validation {    condition     = contains(["t2.micro", "t2.small", "t2.medium"], var.instance_type)    error_message = "Instance type must be t2.micro, t2.small, or t2.medium."  }}
variable "database_password" {  description = "Password for the database admin user"  type        = string  sensitive   = true}

Outputs

Every output must include description:

hcl

output "instance_id" {  description = "ID of the EC2 instance"  value       = aws_instance.web.id}
output "database_password" {  description = "Database administrator password"  value       = aws_db_instance.main.password  sensitive   = true}

output "instance_id" {  description = "ID of the EC2 instance"  value       = aws_instance.web.id}
output "database_password" {  description = "Database administrator password"  value       = aws_db_instance.main.password  sensitive   = true}

Dynamic Resource Creation

Prefer for_each over count

hcl

# Bad - count for multiple resourcesresource "aws_instance" "web" {  count = var.instance_count  tags  = { Name = "web-${count.index}" }}
# Good - for_each with named instancesvariable "instance_names" {  type    = set(string)  default = ["web-1", "web-2", "web-3"]}
resource "aws_instance" "web" {  for_each = var.instance_names  tags     = { Name = each.key }}

# Bad - count for multiple resourcesresource "aws_instance" "web" {  count = var.instance_count  tags  = { Name = "web-${count.index}" }}
# Good - for_each with named instancesvariable "instance_names" {  type    = set(string)  default = ["web-1", "web-2", "web-3"]}
resource "aws_instance" "web" {  for_each = var.instance_names  tags     = { Name = each.key }}

count for Conditional Creation

hcl

resource "aws_cloudwatch_metric_alarm" "cpu" {  count = var.enable_monitoring ? 1 : 0
  alarm_name = "high-cpu-usage"  threshold  = 80}

resource "aws_cloudwatch_metric_alarm" "cpu" {  count = var.enable_monitoring ? 1 : 0
  alarm_name = "high-cpu-usage"  threshold  = 80}

Security Best Practices

Refer to SECURITY.md. It includes guidance on encrypting resources, preventing sensitive data in state, and secure configurations.

Version Pinning

hcl

terraform {  required_version = ">= 1.14"
  required_providers {    aws = {      source  = "hashicorp/aws"      version = "~> 6.0"    }  }}

terraform {  required_version = ">= 1.14"
  required_providers {    aws = {      source  = "hashicorp/aws"      version = "~> 6.0"    }  }}

Use the latest major version of each provider and the latest minor version of Terraform, unless otherwise constrained by a dependency lock file or by other modules used by the configuration.

Version constraint operators:

= 1.0.0 - Exact version
>= 1.0.0 - Greater than or equal
~> 1.0 - Allow rightmost component to increment
>= 1.0, < 2.0 - Version range

Provider Configuration

hcl

provider "aws" {  region = "us-west-2"
  default_tags {    tags = {      ManagedBy = "Terraform"      Project   = var.project_name    }  }}
# Aliased provider for multi-regionprovider "aws" {  alias  = "east"  region = "us-east-1"}

provider "aws" {  region = "us-west-2"
  default_tags {    tags = {      ManagedBy = "Terraform"      Project   = var.project_name    }  }}
# Aliased provider for multi-regionprovider "aws" {  alias  = "east"  region = "us-east-1"}

Version Control

Never commit:

terraform.tfstate, terraform.tfstate.backup
.terraform/ directory
*.tfplan
.tfvars files with sensitive data

Always commit:

All .tf configuration files
.terraform.lock.hcl (dependency lock file)

Validation Tools

Run before committing:

Additional tools:

tflint - Linting and best practices
checkov / tfsec - Security scanning

Code Review Checklist

Based on: HashiCorp Terraform Style Guide

來源與署名

來源：hashicorp/agent-skills位於plugins/terraform/skills/terraform-style-guide提交f706481

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檢舉或申請下架

Terraform Style Guide

Terraform Style Guide

Code Generation Strategy

File Organization

Example Structure

Code Formatting

Indentation and Alignment

Block Organization

Naming Conventions

Variables

Outputs

Dynamic Resource Creation

Prefer for_each over count

count for Conditional Creation

Security Best Practices

Version Pinning

Provider Configuration

Version Control

Validation Tools

Code Review Checklist

來源與署名

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