Class: Dacs::AppConfig

Inherits:
Hash
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/dacs/app_config.rb

Overview

This configuration system is for deployment-specific values, such as AWS keys and API URLs.

Configuration values can be accessed anywhere in the app using the AppConfig class, which behaves like a Hash.

Note that all keys are strings - not symbols.

Configuration keys can be set at three levels: hardcoded defaults, in config/<APPNAME>.yml, or in the environment.

  1. Defaults are set below, in the initializer.

  2. Defaults will be overridden by config/<APPNAME>.yml. This file is broken into per-environment sections just like database.yml, so to configure for the development environment, you’d use something like the following in config/<APPNAME>.yml:

    development:

    api_base_uri: http://localhost:4567
authenticate: false
aws_access_key: 'XXX...'
aws_secret_key: 'XXX...'
simpledb_domain: 'my_sandbox_domain'

  3. Values in <APPNAME>.yml will be overidden by <APPNAME>_* environment variables. For instance, to set key ‘foo’ = ‘bar’, set APPNAME_FOO=‘bar’ in the process environment.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ AppConfig

Returns a new instance of AppConfig.



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# File 'lib/dacs/app_config.rb', line 94

def initialize
  raise "You must initialize with Dacs::AppConfig.init!()" unless @@options
  @app_name     = @@options[:app_name]
  @config_path  = @@options[:config_path]
  @logger       = @@options[:logger]
  @environment  = @@options[:environment]
  @defaults     = self.class.schema.defaults 
  find_or_create_config_file!

  defaults_source = DefaultSource.new(@defaults)
  file_source     = FileSource.new(config_path, @environment)
  env_source      = EnvironmentSource.new(@app_name)

  load_values!(self.class.schema, env_source, file_source, defaults_source)
end

Instance Attribute Details

#app_name ⇒ Object (readonly)

Returns the value of attribute app_name.



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# File 'lib/dacs/app_config.rb', line 89

def app_name
  @app_name
end

#config_path ⇒ Object (readonly)

Returns the value of attribute config_path.



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# File 'lib/dacs/app_config.rb', line 91

def config_path
  @config_path
end

#environment ⇒ Object (readonly)

Returns the value of attribute environment.



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# File 'lib/dacs/app_config.rb', line 92

def environment
  @environment
end

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/dacs/app_config.rb', line 90

def logger
  @logger
end

Class Method Details

.environment ⇒ Object 



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# File 'lib/dacs/app_config.rb', line 85

def self.environment
  @@options[:environment]
end

.init!(app_name, options = {}) ⇒ Object

Usage:

Dacs::AppConfig.init!('example', 
  :environment => 'development',
  :logger      => Logger.new($stdout)) do |config|

  config.key 'foo', :default => 'default_foo'
  config.key 'bar', :default => 'default_bar'
  config.key 'baz', :default => 'default_baz'
end



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# File 'lib/dacs/app_config.rb', line 59

def self.init!(app_name, options={})
  @instance = nil
  @@options = options.merge(:app_name => app_name)
  @@options[:app_root]     ||= Pathname(Dir.pwd)
  @@options[:config_path]  ||= @@options[:app_root] + 'config' + "#{app_name}.yml"
  @@options[:logger]       ||= ::Logger.new($stderr)
  @@options[:environment]  ||= :development
  @@options[:defaults]     ||= {}
  if block_given?
    schema = Schema.new
    yield(schema)
    @@schema = schema
  else
    @@schema = PermissiveSchema.new(@@options[:defaults])
  end
  self.instance
end

.instance ⇒ Object 



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# File 'lib/dacs/app_config.rb', line 77

def self.instance
  @instance ||= new
end

.schema ⇒ Object 



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# File 'lib/dacs/app_config.rb', line 81

def self.schema
  @@schema
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/dacs/app_config.rb', line 117

def [](key)
  super(key).value
end

#dump ⇒ Object 



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# File 'lib/dacs/app_config.rb', line 128

def dump
  table = Table(%w[Key Value Source])
  each_pair do |key, configured_value|
    table << [key, configured_value.value, configured_value.source.to_s]
  end
  table.as(:text)
end

#fetch(key, &block) ⇒ Object 



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# File 'lib/dacs/app_config.rb', line 121

def fetch(key, &block)
  case result = super(key, &block)
  when ConfiguredValue then result.value
  else result
  end
end

#source(key) ⇒ Object 



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# File 'lib/dacs/app_config.rb', line 110

def source(key)
  configured_value = Hash.instance_method(:fetch).bind(self).call(key.to_s) do
    raise ConfigurationError, "No such key '#{key}'"
  end
  configured_value.source.to_s
end