variables

Variables Best Practices – Terraform

Demonstrates Terraform variable templatization covering:

• Variable types: string, number, bool, list, map, object, tuple
• Input validation with validation blocks
• Sensitive variables for secrets
• locals for computed/derived values
• Conditional expressions and for expressions
• Variable grouping with object types
• terraform.tfvars and .auto.tfvars patterns
• Environment-specific overrides

Files

File	Description
main.tf	Example showing variable usage patterns
variables.tf	Comprehensive variable definitions
locals.tf	Local value computations
terraform.tfvars.example	Example variable file
environments/dev.tfvars	Dev environment overrides
environments/prod.tfvars	Prod environment overrides

Usage

# Dev environment
terraform plan -var-file="environments/dev.tfvars"

# Prod environment
terraform plan -var-file="environments/prod.tfvars"

# Override single variable
terraform plan -var="instance_count=3"

# Sensitive variable via environment variable (avoids storing in files)
export TF_VAR_db_password="my-secret-password"
terraform plan