Class: Interferon::DynamicLoader

Inherits:
Object
  • Object
show all
Includes:
Logging
Defined in:
lib/interferon/loaders.rb

Overview

this is a type of class that can dynamically load other classes based on a ‘type’ string

Instance Method Summary collapse

Methods included from Logging

configure_logger_for, #log, #statsd

Constructor Details

#initialize(custom_paths) ⇒ DynamicLoader

Returns a new instance of DynamicLoader.



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# File 'lib/interferon/loaders.rb', line 13

def initialize(custom_paths)
  @paths = []
  custom_paths.each do |custom_path|
    @paths << File.expand_path(custom_path)
  end

  initialize_attributes
end

Instance Method Details

#get_all(sources) ⇒ Object 



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# File 'lib/interferon/loaders.rb', line 29

def get_all(sources)
  instances = []

  sources.each_with_index do |source, idx|
    type    =   source['type']
    enabled = !!source['enabled']
    options =   source['options'] || {}

    if type.nil?
      log.warn("#{@loader_for} ##{idx} does not have a 'type' set; 'type' is required")
      next
    end

    unless enabled
      log.info("skipping #{@loader_for} #{type} because it's not enabled")
      next
    end

    instance = get_klass(type).new(options)
    instances << instance
  end

  instances
end

#get_klass(type) ⇒ Object 



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# File 'lib/interferon/loaders.rb', line 54

def get_klass(type)
  # figure out what we're getting based on the type
  filename = type.downcase
  type_parts = filename.split('_')
  class_name = type_parts.map(&:capitalize).join

  # ideally, we'll put a constant into this variable
  klass = nil

  # first, try getting from custom paths
  @paths.each do |path|
    full_path = "#{path}/#{@type_path}/#{filename}"

    begin
      require full_path
      klass = @module.const_get(class_name)
    rescue LoadError => e
      log.debug("LoadError looking for #{@loader_for} file #{type} at #{full_path}: #{e}")
    rescue NameError => e
      log.debug(
        "NameError looking for #{@loader_for} class #{class_name}  in #{full_path}: #{e}"
      )
    end

    break if klass
  end

  # if that doesn't work, try getting from this repo via require_relative
  if klass.nil?
    begin
      relative_filename = "./#{@type_path}/#{filename}"

      require_relative relative_filename
      klass = @module.const_get(class_name)
    rescue LoadError => e
      raise ArgumentError,\
            "Loading Error; interferon does not define #{@loader_for} #{type}: #{e}"
    rescue NameError => e
      raise ArgumentError,\
            "Name Error; class #{class_name} is not defined in #{relative_filename}: #{e}"
    end
  end

  klass
end

#initialize_attributes ⇒ Object

this should be overridden in specific loaders



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# File 'lib/interferon/loaders.rb', line 23

def initialize_attributes
  @loader_for = 'class'
  @type_path  = ''
  @module     = ::Interferon
end