Module: ConstConf::EnvDirExtension

Includes:
FilePlugin
Defined in:
lib/const_conf/env_dir_extension.rb

Overview

An extension that enables loading environment variable values from files in a directory structure, where each file’s basename becomes an environment variable name.

This extension is particularly useful for implementing a pattern, where each environment variable is stored in its own file with the same name as the variable. For example:

./env/DATABASE_URL    # contains: postgresql://localhost/myapp
./env/API_KEY         # contains: sk-1234567890abcdef1234567890abcdef

Usage:

module AppConfig
  include ConstConf

  description 'Application Configuration'

  module EnvDir
    extend ConstConf::EnvDirExtension

    description 'All variables loaded from .env directory'

    # Load all environment variables from .env/*
    load_dotenv_dir('.env/*') {}
  end
end

The loaded settings are automatically:

  • Marked as sensitive (since they might contain secrets)

  • Required (files must exist to be loaded)

  • Chomped to remove trailing whitespace

  • Named using the file basename in uppercase and without a prefix.

This extension works well alongside manually-defined settings, if you put it into a nested module at the end of your ConstConf config. Settings defined explicitly with ‘set do` blocks before this module take precedence over auto-loaded ones, allowing for a hybrid approach where critical configuration is documented and validated, while additional environment variables can be loaded automatically from files.

The loaded settings appear in AppConfig.view() with proper descriptions showing their source file locations, making it easy to see what configuration is being used.

Instance Method Summary collapse

Methods included from FilePlugin

#file

Instance Method Details

#load_dotenv_dir(*globs) {|binding| ... } ⇒ Object

Loads environment variable values from dotenv-style files into configuration constants.

This method processes glob patterns to find files, reads their content using the FilePlugin, and defines configuration settings for each file’s content. It automatically creates constants with uppercase names based on the filename and configures them as required and sensitive settings with chomped values.

environment variables the correct context

Parameters:

  • globs (Array<String>) —

    glob patterns to match files containing

Yields:

  • (binding) —

    yields the binding of the caller to allow evaluation in

Yield Parameters:

  • binding (Binding) —

    the binding to evaluate constants in



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# File 'lib/const_conf/env_dir_extension.rb', line 61

def load_dotenv_dir(*globs, &block)
  block or raise ArgumentError, '&block argument is required'
  globs.each do |glob|
    Dir[glob].each do |path|
      my_file = file(path, required: true)
      eval('self', block.__send__(:binding)).class_eval do
      name = File.basename(path).upcase
      const_set(
        name,
        set do
          prefix ''
          description "Value of #{name.inspect} from #{File.dirname(path).inspect}"
          default my_file
          decode(&:chomp)
          required true
          sensitive true
        end
      )
      rescue ConstConf::SettingAlreadyDefined
      end
    end
  end
  self
end