Module config 

Configuration Module for Create Command

This module provides configuration Data Transfer Objects (DTOs) and validation for creating deployment environments. It sits at the boundary between external configuration sources (JSON files, CLI arguments, etc.) and the internal domain model.

Architecture

The configuration DTOs in this module are specific to the create command and are distinct from both the domain and adapter layers:

• Configuration DTOs (application::command_handlers::create::config): String-based configuration objects that deserialize from external sources (JSON, TOML, CLI)
• Domain Layer (domain::environment): Strongly-typed domain entities with business validation
• Adapter Layer (adapters::ssh): Infrastructure-specific implementations

Key Components

Value Objects

• EnvironmentCreationConfig - Top-level configuration for environment creation
• SshCredentialsConfig - SSH credentials configuration (config layer)
• EnvironmentSection - Environment-specific settings

Provider Configuration

Provider configuration is organized in the provider submodule:

• ProviderSection - Tagged enum for provider-specific settings
• LxdProviderSection - LXD provider configuration
• HetznerProviderSection - Hetzner provider configuration

Note: SshCredentialsConfig (config layer) is distinct from adapters::ssh::SshCredentials (adapter layer). The config version uses strings for paths and usernames, while the adapter version uses domain types.

Type Conversion

Configuration objects provide to_* methods that convert string-based configuration to strongly-typed domain objects:

• String environment name → EnvironmentName
• String username → Username
• String paths → PathBuf

Error Handling

All errors implement the .help() method following the project’s tiered help system pattern, providing actionable guidance for resolving issues.

Usage Example

use torrust_tracker_deployer_lib::application::command_handlers::create::config::{
    EnvironmentCreationConfig, EnvironmentSection, SshCredentialsConfig,
    ProviderSection, LxdProviderSection
};
use torrust_tracker_deployer_lib::domain::environment::EnvironmentParams;
use torrust_tracker_deployer_lib::domain::Environment;
use chrono::{TimeZone, Utc};

// Deserialize configuration from JSON
let json = r#"{
    "environment": {
        "name": "dev"
    },
    "ssh_credentials": {
        "private_key_path": "fixtures/testing_rsa",
        "public_key_path": "fixtures/testing_rsa.pub"
    },
    "provider": {
        "provider": "lxd",
        "profile_name": "torrust-profile-dev"
    },
    "tracker": {
        "core": {
            "database": {
                "driver": "sqlite3",
                "database_name": "tracker.db"
            },
            "private": false
        },
        "udp_trackers": [
            {
                "bind_address": "0.0.0.0:6969"
            }
        ],
        "http_trackers": [
            {
                "bind_address": "0.0.0.0:7070"
            }
        ],
        "http_api": {
            "bind_address": "0.0.0.0:1212",
            "admin_token": "MyAccessToken"
        }
    }
}"#;

let config: EnvironmentCreationConfig = serde_json::from_str(json)?;

// Convert to validated domain parameters using TryInto
let params: EnvironmentParams = config.try_into()?;

// Create domain entity using the factory pattern
let created_at = Utc.with_ymd_and_hms(2025, 1, 1, 0, 0, 0).unwrap();
let working_dir = std::path::Path::new("/tmp/my-env");
let environment = Environment::create(params, working_dir, created_at)?;

Validation Strategy

Validation occurs in two phases:

1. Format Validation (during conversion):

   • Environment name format (via EnvironmentName::new())
   • Username format (via Username::new())
   • Path string to PathBuf conversion

2. Business Validation (during conversion):

   • SSH key file existence
   • SSH key file accessibility
   • Domain-specific business rules

Design Principles

• Type Safety: String-based config → strongly-typed domain objects
• Single Responsibility: Config objects only handle deserialization and conversion
• Explicit Errors: All validation errors are explicit enum variants with context
• Actionable Feedback: All errors provide .help() with troubleshooting steps
• Clean Separation: Config layer is distinct from domain and adapter layers

Re-exports

pub use backup::BackupSection;

pub use builder::EnvironmentCreationConfigBuildError;

pub use builder::EnvironmentCreationConfigBuilder;

pub use environment_config::EnvironmentCreationConfig;

pub use environment_config::EnvironmentSection;

pub use errors::ConfigLoadError;

pub use errors::CreateConfigError;

pub use grafana::GrafanaSection;

pub use https::HttpsSection;

pub use prometheus::PrometheusSection;

pub use provider::HetznerProviderSection;

pub use provider::LxdProviderSection;

pub use provider::ProviderSection;

pub use ssh_credentials_config::SshCredentialsConfig;

Modules

backup

Backup Configuration DTO (Application Layer)

builder

Fluent builder for EnvironmentCreationConfig.

environment_config

Environment creation configuration value object

errors

Error types for the create-config module.

grafana

Grafana Configuration DTO (Application Layer)

https

HTTPS Configuration DTOs (Application Layer)

prometheus

Prometheus Configuration DTO (Application Layer)

provider

Provider Configuration Types (Application Layer)

ssh_credentials_config

SSH credentials configuration value object

tracker

Tracker Configuration DTOs (Application Layer)

validated_params

DTO to Domain Conversion for Environment Parameters