anyway-config-coder

Anyway Config Coder

Never use ENV directly or Rails credentials. Wrap all configuration in typed anyway_config classes.

# WRONG
api_key = ENV["GEMINI_API_KEY"]

# RIGHT
class GeminiConfig < Anyway::Config
  attr_config :api_key, timeout: 30
  required :api_key
end
GeminiConfig.new.api_key

Configuration Class Pattern

# config/configs/gemini_config.rb
class GeminiConfig < Anyway::Config
  attr_config :api_key, model: "gemini-pro", timeout: 30, max_retries: 3
  required :api_key

  def configured? = api_key.present?
end

ENV auto-mapping: GeminiConfig -> GEMINI_API_KEY, GEMINI_MODEL, etc. Override prefix with config_name :payment.

Nested config uses hash defaults, accessed via dot notation: AppConfig.new.database.host.

Singleton Pattern (Recommended)

class GeminiConfig < Anyway::Config
  attr_config :api_key, :model

  class << self
    def instance = @instance ||= new
  end
end

GeminiConfig.instance.api_key

Directory Structure

config/
├── configs/          # Ruby config classes
│   ├── gemini_config.rb
│   └── stripe_config.rb
└── settings/         # YAML overrides (optional)
    └── gemini.yml

YAML files use default: &default with environment-specific overrides (development:, test:, production:).

Validation

class StorageConfig < Anyway::Config
  attr_config :bucket, :region, :access_key_id, :secret_access_key
  required :bucket, :region
  required :access_key_id, :secret_access_key, env: :production  # Conditional

  def validate!
    super
    raise_validation_error("Invalid region") unless %w[us-east-1 us-west-2 eu-west-1].include?(region)
  end
end

Type Coercion

class ApiConfig < Anyway::Config
  # Automatic coercion
  attr_config timeout: 30       # Integer
  attr_config enabled: true     # Boolean
  attr_config rate: 1.5         # Float

  # Coerce arrays from comma-separated strings
  coerce_types allowed_origins: {
    type: :string,
    array: true
  }
  # ALLOWED_ORIGINS="example.com,other.com" => ["example.com", "other.com"]
end

Testing Configurations

Test defaults, required validations, and computed methods. Override in tests with with_env:

RSpec.describe GeminiConfig do
  it "requires api_key" do
    expect { described_class.new(api_key: nil) }.to raise_error(Anyway::Config::ValidationError)
  end
end

# spec/support/anyway_config.rb - global override
RSpec.configure do |config|
  config.around(:each) do |example|
    with_env("GEMINI_API_KEY" => "test-key") { example.run }
  end
end

Common Patterns

API Client Config

Add client_options helper to build connection hashes:

class OpenAIConfig < Anyway::Config
  attr_config :api_key, :organization_id, model: "gpt-4", max_tokens: 1000
  required :api_key

  def client_options = { access_token: api_key, organization_id: }.compact
end

Multi-Provider Config

Use predicate methods and case for provider-specific options:

class StorageConfig < Anyway::Config
  attr_config provider: "local", bucket: nil, endpoint: nil

  def s3? = provider == "s3"
  def local? = provider == "local"
  def service_options = case provider when "s3" then s3_options else local_options end
end

Anti-Patterns

Anti-Pattern	Problem	Solution
Direct ENV["KEY"]	No type safety, scattered	Config class
ENV.fetch everywhere	Duplication, no validation	Centralized config
Rails credentials	Complex, hard to test	anyway_config classes
Hardcoded secrets	Security risk	Environment variables
Magic strings	Typos, no IDE support	Config constants

Detailed References

• references/advanced-patterns.md - Dynamic configs, callbacks, inheritance