dnet-whois/lib/config.rb

# Class that reads the configuration file and validates and provides the values in it.
class Config
  require 'psych'

  def initialize(args)
    # Ensure data types of arguments
    raise ArgumentError, 'Wrong argument format' unless args.is_a? Hash
    raise ArgumentError, 'Configuration file must be a string' unless args[:configuration_file].is_a? String

    @config_file = args[:configuration_file]
  end

  # Reads the configuration file
  def read
    # If the configuration file is read twice, there is
    # a logic error somewhere.
    # The program should not be executed any further.
    raise 'Configuration file already readed.' if @config

    # Ensure that the file exists and is readable.
    raise ArgumentError, 'Configuration file does not exist.' unless File.file? @config_file
    raise ArgumentError, 'Configuration file is not readable.' unless File.readable? @config_file

    # Read file and try to load it.
    file_cnt = File.read @config_file
    config = Psych.safe_load file_cnt

    raise 'Failed to parse configuration file' unless config.is_a? Hash

    # Check whether the configuration is valid - that is, whether the required
    # values have been specified and whether they are of the correct type.

    # Section Registry
    raise 'Configuration file has no key "registry"' unless config.key? 'registry'
    raise '"registry" must be of type hash' unless config['registry'].is_a? Hash

    ## Section Registry Directory
    raise 'Configuration file has no key "directory"' unless config['registry'].key? 'directory'
    raise '"directory" must be of type string' unless config['registry']['directory'].is_a? String

    ## Section Registry Reload Interval
    raise 'Configuration file has no key "reload_interval"' unless config['registry'].key? 'reload_interval'
    raise '"reload_interval" must be of type integer' unless config['registry']['reload_interval'].is_a? Integer

    # Section whoisd
    raise 'Configuration file has no key "whoisd"' unless config.key? 'whoisd'
    raise '"whoisd" must be of type hash' unless config['whoisd'].is_a? Hash

    ## Section whoisd host
    raise 'Configuration file has no key "host"' unless config['whoisd'].key? 'host'
    raise '"host" must be of type string' unless config['whoisd']['host'].is_a? String

    ## Section whoisd port
    raise 'Configuration file has no key "port"' unless config['whoisd'].key? 'port'
    raise '"port" must be of type integer' unless config['whoisd']['port'].is_a? Integer

    ## Section Logging
    raise 'Configuration file has no key "logging"' unless config.key? 'logging'
    raise '"logging" must be of type string' unless config['logging'].is_a? String

    # Removing accidental whitespaces
    config['registry']['directory'].strip!
    config['whoisd']['host'].strip!
    config['logging'].strip!
    config['logging'].downcase!
    config['registry']['directory'] = File.absolute_path(config['registry']['directory'])

    # After reading the configuration should
    # not be changed anymore
    config.freeze

    @config = config

    return self
  end

  # Returns the registry directory path.
  # If the configuration was not read, a RuntimeError is raised.
  #
  # @return [String]
  def registry_directory
    raise 'Configuration file not readed' unless @config

    return @config['registry']['directory']
  end

  # Returns the registry reload interval.
  # If the configuration was not read, a RuntimeError is raised.
  #
  # @return [String]
  def registry_reload_interval
    raise 'Configuration file not readed' unless @config

    return @config['registry']['reload_interval']
  end

  # Returns the whois endpoint as array.
  # If the configuration was not read, a RuntimeError is raised.
  #
  # @return [Array] [Host, Port]
  def whois_endpoint
    raise 'Configuration file not readed' unless @config

    return @config['whoisd']['host'], @config['whoisd']['port']
  end

  # Returns the logging level.
  # If the configuration was not read, a RuntimeError is raised.
  #
  # @return [String]
  def logging_level
    raise 'Configuration file not readed' unless @config

    return @config['logging']
  end
end