🔍 EnvCheck

env_check is a lightweight Ruby gem to validate and document your environment variables.
It ensures critical env vars are present and properly formatted before your app boots or deploys.

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🚀 Features

• ✅ Validate required environment variables
• ⚠️ Warn on missing or invalid optional variables
• 🔒 Type checking (boolean, integer, URL, email)
• 📁 YAML-based configuration
• 🔧 Works with any Ruby or Rails app
• 🌱 Supports .env file via dotenv (optional)
• 🎯 Programmatic API for custom integrations
• 📊 Detailed validation results

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Installation

Add this line to your application's Gemfile:

gem 'env_check'

And then execute:

$ bundle install

Ruby and Rails Compatibility

Ruby Version Support

• Ruby 3.0+ - Fully supported
• Ruby 3.1+ - Fully supported
• Ruby 3.2+ - Fully supported
• Ruby 3.3+ - Fully supported
• Ruby 3.4+ - Fully supported

Rails Version Support

This gem is framework-agnostic and works with any Ruby application. For Rails applications, it supports:

Rails Version	Ruby Version	Support Status
Rails 8.0+	Ruby 3.2+	✅ Supported
Rails 7.2+	Ruby 3.1+	✅ Supported
Rails 7.1+	Ruby 3.1+	✅ Supported
Rails 7.0+	Ruby 2.7+	✅ Supported
Rails 6.1+	Ruby 2.5+	✅ Supported
Rails 6.0+	Ruby 2.5+	✅ Supported
Rails 5.x	Ruby 2.2+	⚠️ Should work but not actively tested

Note: While the gem doesn't directly depend on Rails, it's been designed to work seamlessly in Rails environments and integrates well with Rails' environment variable patterns.

Or install manually:

gem install env_check

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⚡ Quick Start

1. Generate Configuration

env_check init

This creates a configuration file using smart defaults:

• Simple projects: .env_check.yml (root level, pairs with .env)
• Rails projects: config/env_check.yml (Rails convention)

Example configuration:

# EnvCheck Configuration
# Required environment variables (must be present and non-empty)
required:
  - DATABASE_URL
  - SECRET_KEY_BASE

# Optional environment variables with type validation
optional:
  DEBUG: boolean          # true, false, 1, 0, yes, no
  PORT: integer          # numeric values only
  API_URL: url           # must start with http:// or https://
  ADMIN_EMAIL: email     # valid email format

2. Validate Environment

env_check check

Output:

✅ DATABASE_URL is set
✅ SECRET_KEY_BASE is set
⚠️  DEBUG should be a boolean, got 'maybe'
❌ Missing required ENV: API_KEY

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🛠 Usage

Command Line Interface

# Create configuration file
env_check init

# Validate environment variables
env_check check

# Show version
env_check version

Programmatic Usage

require 'env_check'

# Basic validation (returns Result object)
result = EnvCheck.verify

if result.success?
  puts "✅ All environment variables are valid!"
  puts "Valid vars: #{result.valid_vars.join(', ')}"
else
  puts "❌ Validation failed!"
  puts "Errors: #{result.errors.join(', ')}"
  puts "Warnings: #{result.warnings.join(', ')}"
end

# Validate with custom config file
result = EnvCheck.verify("path/to/custom.yml")

# Validate with inline configuration
result = EnvCheck.verify_with_config({
  "required" => ["API_KEY", "DATABASE_URL"],
  "optional" => { "DEBUG" => "boolean" }
})

# Legacy method (raises exception on failure)
begin
  EnvCheck.verify!
  puts "✅ Validation passed!"
rescue EnvCheck::Error => e
  puts "❌ #{e.message}"
  exit 1
end

Rails Integration

Add to your config/application.rb or initializer:

# config/initializers/env_check.rb
EnvCheck.verify! if Rails.env.production?

Advanced Rails Integration Patterns

1. Environment-Specific Validation

# config/initializers/env_check.rb
Rails.application.config.after_initialize do
  # Load Rails-specific config
  config_file = Rails.root.join('config', 'env_check.yml')
  
  if config_file.exist?
    result = EnvCheck.verify(config_file)
    unless result.success?
      Rails.logger.error "Environment validation failed: #{result.errors.join(', ')}"
      
      # Only raise in production
      raise EnvCheck::Error, result.errors.join(', ') if Rails.env.production?
    end
  end
end

2. Controller Integration

class ApplicationController < ActionController::Base
  before_action :validate_critical_env_vars, if: -> { Rails.env.production? }
  
  private
  
  def validate_critical_env_vars
    result = EnvCheck.verify_with_config({
      "required" => ["DATABASE_URL", "SECRET_KEY_BASE", "RAILS_MASTER_KEY"]
    })
    
    unless result.success?
      render json: { error: 'Service temporarily unavailable' }, status: 503
    end
  end
end

3. Health Check Endpoint

# config/routes.rb
Rails.application.routes.draw do
  get '/health/env', to: 'health#env_check'
end

# app/controllers/health_controller.rb
class HealthController < ApplicationController
  def env_check
    result = EnvCheck.verify
    
    if result.success?
      render json: { 
        status: 'ok', 
        valid_vars: result.valid_vars.count,
        warnings: result.warnings
      }
    else
      render json: { 
        status: 'error', 
        errors: result.errors 
      }, status: 422
    end
  end
end

4. Environment-Specific Configuration

Create your config file (.env_check.yml or config/env_check.yml):

default: &default
  optional:
    DEBUG: boolean
    LOG_LEVEL: string

development:
  <<: *default
  required:
    - DATABASE_URL
    - SECRET_KEY_BASE

test:
  <<: *default  
  required:
    - SECRET_KEY_BASE
  optional:
    DATABASE_URL: url

production:
  <<: *default
  required:
    - DATABASE_URL
    - SECRET_KEY_BASE  
    - RAILS_MASTER_KEY
    - REDIS_URL
  optional:
    MEMCACHED_URL: url
    CDN_HOST: url
    SMTP_HOST: string

Rake Integration

# In your Rakefile or Rails app
require 'env_check'

# Use the built-in rake task
rake env:check

---

🔧 Configuration

Supported Types

• boolean: true, false, 1, 0, yes, no (case-insensitive)
• integer: Positive or negative integers (123, -456)
• url: URLs starting with http:// or https://
• email: Valid email addresses
• string: Any value (default, no validation)

Configuration File

# config/env_check.yml
required:
  - DATABASE_URL
  - SECRET_KEY_BASE
  - API_KEY

optional:
  # Type validations
  DEBUG: boolean
  PORT: integer
  API_URL: url
  ADMIN_EMAIL: email
  
  # Environment-specific
  RAILS_ENV: string
  RACK_ENV: string

Smart Configuration Discovery

EnvCheck automatically discovers your configuration file using this priority:

1. .env_check.yml (root level - simple projects, pairs with .env)
2. config/env_check.yml (Rails convention - if config/ directory exists)
3. Custom path via --config flag or ENV_CHECK_CONFIG environment variable

# Auto-discovery (checks .env_check.yml, then config/env_check.yml)
env_check check

# Explicit path
env_check check --config custom/path.yml

# Via environment variable
ENV_CHECK_CONFIG=custom/path.yml env_check check

# Via Ruby API
EnvCheck.verify("custom/path.yml")

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🧪 Testing

Run the test suite:

bundle exec rspec

Run linting:

bundle exec rubocop

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🤝 Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Please make sure to update tests and run the linter before submitting.

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📄 License

The gem is available as open source under the terms of the MIT License.

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🙏 Changelog

See CHANGELOG.md for version history and changes.