Random UUID

The random_uuid resource generates universally unique identifiers (UUIDs) following the RFC 4122 standard. It provides deterministic UUID generation that remains consistent across multiple runs.

Use Cases

As a lab author, you can use random_uuid resources to:

• Unique Identifiers: Generate globally unique resource identifiers that never conflict across lab instances
• Database Keys: Create unique primary keys, foreign keys, or correlation IDs for database operations

Random UUID resources provide RFC 4122 compliant UUIDs with guaranteed uniqueness and consistent generation.

HCL Syntax

Basic Syntax

resource "random_uuid" "name" {}

Full Syntax

resource "random_uuid" "name" {}

Fields

This resource takes no input parameters. UUIDs are generated automatically.

Computed Attributes

These attributes are set by the system after UUID generation:

Field	Type	Description
value	string	The generated UUID in standard format (e.g., "550e8400-e29b-41d4-a716-446655440000")

Validation Rules

• UUIDs follow the RFC 4122 standard format
• Generated values remain constant across multiple runs (idempotent)
• UUIDs are globally unique with extremely low collision probability
• Standard format includes hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Examples

Simple UUID Generation

resource "random_uuid" "session_id" {}

output "session_id" {
  value = resource.random_uuid.session_id.value  # e.g., "550e8400-e29b-41d4-a716-446655440000"
}

Database Record ID

resource "random_uuid" "user_id" {}

resource "template" "user_record" {
  source = <<-EOF
    INSERT INTO users (id, name, email) VALUES (
      '${resource.random_uuid.user_id.value}',  -- e.g., 'a1b2c3d4-e5f6-4321-9876-123456789abc'
      'John Doe',
      'john@example.com'
    );
  EOF

  destination = "./init_user.sql"
}

Container Naming

resource "random_uuid" "container_id" {}

resource "container" "app" {
  image {
    name = "myapp:latest"
  }

  environment = {
    INSTANCE_ID = resource.random_uuid.container_id.value  # e.g., "550e8400-e29b-41d4-a716-446655440000"
  }
}

API Correlation IDs

resource "random_uuid" "correlation_id" {}

resource "http" "api_request" {
  method = "POST"
  url = "https://api.example.com/data"

  headers = {
    "Content-Type" = "application/json"
    "X-Correlation-ID" = resource.random_uuid.correlation_id.value  # e.g., "a1b2c3d4-e5f6-4321-9876-123456789abc"
  }

  payload = jsonencode({
    request_id = resource.random_uuid.correlation_id.value  # e.g., "a1b2c3d4-e5f6-4321-9876-123456789abc"
    data = "lab_data"
  })
}

Multiple UUID Usage

resource "random_uuid" "lab_instance_id" {}
resource "random_uuid" "transaction_id" {}
resource "random_uuid" "session_token" {}

resource "template" "lab_config" {
  source = <<-EOF
    lab:
      instance_id: ${resource.random_uuid.lab_instance_id.value}      # e.g., "123e4567-e89b-12d3-a456-426614174000"
      transaction_id: ${resource.random_uuid.transaction_id.value}    # e.g., "987fcdeb-51a2-43d1-9b77-332168459012"
      session_token: ${resource.random_uuid.session_token.value}      # e.g., "456789ab-cdef-1234-5678-90abcdef1234"

    database:
      connection_id: ${resource.random_uuid.lab_instance_id.value}

    logging:
      trace_id: ${resource.random_uuid.transaction_id.value}
  EOF

  destination = "./lab-config.yaml"
}

Message Queue Integration

resource "random_uuid" "queue_id" {}
resource "random_uuid" "consumer_id" {}

resource "container" "message_producer" {
  image {
    name = "rabbitmq:management"
  }

  environment = {
    RABBITMQ_DEFAULT_QUEUE = "lab-queue-${substr(resource.random_uuid.queue_id.value, 0, 8)}"  # e.g., "lab-queue-abc12345"
    CONSUMER_ID = resource.random_uuid.consumer_id.value  # e.g., "def67890-1234-5678-9abc-def123456789"
  }
}

Cloud Resource Naming

resource "random_uuid" "resource_suffix" {}

resource "terraform" "aws_resources" {
  source = "./terraform"

  variables = {
    # Use UUID for globally unique resource names
    bucket_name = "lab-bucket-${substr(resource.random_uuid.resource_suffix.value, 0, 12)}"     # e.g., "lab-bucket-550e8400e29b"
    vpc_name = "lab-vpc-${substr(resource.random_uuid.resource_suffix.value, 24, 8)}"           # e.g., "lab-vpc-44665544"
    cluster_id = resource.random_uuid.resource_suffix.value                                      # e.g., "550e8400-e29b-41d4-a716-446655440000"
  }
}

Best Practices

1. Global Uniqueness: Use UUIDs when you need guaranteed global uniqueness
2. Substring Usage: Extract portions of UUIDs for shorter identifiers when full UUID isn’t needed
3. Consistent Format: Use standard UUID format (with hyphens) for maximum compatibility
4. Resource Naming: Combine UUIDs with descriptive prefixes for readable resource names
5. Database Design: Use UUIDs as primary keys for distributed systems
6. Logging: Include UUIDs in logs for correlation and tracing
7. Documentation: Document UUID usage and purpose in your lab configuration