Module provision 

Provision Command Module

This module implements the delivery-agnostic ProvisionCommandHandler for orchestrating infrastructure provisioning business logic.

Architecture

The ProvisionCommandHandler implements the Command Pattern and uses Dependency Injection to interact with infrastructure services through interfaces:

• Repository Pattern: Persists environment state via EnvironmentRepository
• Clock Abstraction: Provides deterministic time for testing via Clock trait
• Domain-Driven Design: Uses domain objects from domain::environment

Design Principles

• Delivery-Agnostic: Works with CLI, REST API, or any delivery mechanism
• Asynchronous: Uses async/await for network operations
• Explicit State Transitions: Type-safe state machine for environment lifecycle
• Explicit Errors: All errors implement .help() with actionable guidance

Provisioning Workflow

The command handler orchestrates a multi-step workflow:

1. Render OpenTofu templates - Generate infrastructure configuration
2. Initialize OpenTofu - Set up Terraform/OpenTofu backend
3. Validate configuration - Check syntax and consistency
4. Plan infrastructure - Preview changes
5. Apply infrastructure - Provision virtual machines
6. Get instance information - Retrieve IP address and metadata
7. Render Ansible templates - Generate configuration with runtime IP
8. Wait for SSH connectivity - Ensure VM is reachable
9. Wait for cloud-init - Ensure system is ready for configuration

State Management

The command handler integrates with the type-state pattern for environment lifecycle:

• Accepts Environment<Created> as input
• Transitions to Environment<Provisioning> at start
• Returns Environment<Provisioned> on success
• Transitions to Environment<ProvisionFailed> on error

State is persisted after each transition using the injected repository.

Re-exports

pub use errors::ProvisionCommandHandlerError;

pub use handler::ProvisionCommandHandler;

Modules

errors

Error types for the Provision command handler

handler

Provision command handler implementation