Class: Nugrant::Config

Inherits:
Object
  • Object
show all
Defined in:
lib/nugrant/config.rb

Constant Summary collapse

DEFAULT_ARRAY_MERGE_STRATEGY = 
:replace
DEFAULT_PARAMS_FILENAME = 
".nuparams"
DEFAULT_PARAMS_FORMAT = 
:yaml
SUPPORTED_ARRAY_MERGE_STRATEGIES = 
[:concat, :extend, :replace]
SUPPORTED_PARAMS_FORMATS = 
[:json, :yaml]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Config

Creates a new config object that is used to configure an instance of Nugrant::Parameters. See the list of options and how they interact with Nugrant::Parameters.

| Options

* +:params_filename+ - The filename used to fetch parameters from. This
                       will be appended to various default locations.
                       Location are system, project and current that
                       can be tweaked individually by using the options
                       below.
                         Defaults => ".nuparams"
* +:params_format+   - The format in which parameters are to be parsed.
                       Presently supporting :yaml and :json.
                         Defaults => :yaml
* +:current_path+    - The current path has the highest precedence over
                       any other location. It can be be used for many purposes
                       depending on your usage.
                        * A path from where to read project parameters
                        * A path from where to read overriding parameters for a cli tool
                        * A path from where to read user specific settings not to be committed in a VCS
                         Defaults => "./#{@params_filename}"
* +:user_path+       - The user path is the location where the user
                       parameters should resides. The parameters loaded from this
                       location have the second highest precedence.
                         Defaults => "~/#{@params_filename}"
* +:system_path+     - The system path is the location where system wide
                       parameters should resides. The parameters loaded from this
                       location have the third highest precedence.
                         Defaults => Default system path depending on OS + @params_filename
* +:array_merge_strategy+  - This option controls how array values are merged together when merging
                             two Bag instances. Possible values are:
                               * :replace => Replace current values by new ones
                               * :extend => Merge current values with new ones
                               * :concat => Append new values to current ones
                              Defaults => The strategy :replace.
* +:key_error+     - A callback method receiving one argument, the key as a symbol, and that
                     deal with the error. If the callable does not
                     raise an exception, the result of it's execution is returned.
                       Defaults => A callable that throws a KeyError exception.
* +:parse_error+   - A callback method receiving two arguments, the offending filename and
                     the error object, that deal with the error. If the callable does not
                     raise an exception, the result of it's execution is returned.
                       Defaults => A callable that returns the empty hash.



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# File 'lib/nugrant/config.rb', line 131

def initialize(options = {})
  @params_filename = options[:params_filename] || DEFAULT_PARAMS_FILENAME
  @params_format = options[:params_format] || DEFAULT_PARAMS_FORMAT

  @current_path = Config.fixup_path(options[:current_path], ".", @params_filename)
  @user_path = Config.fixup_path(options[:user_path], Config.default_user_path(), @params_filename)
  @system_path = Config.fixup_path(options[:system_path], Config.default_system_path(), @params_filename)

  @array_merge_strategy = options[:array_merge_strategy] || :replace

  @key_error = options[:key_error] || Proc.new do |key|
    raise KeyError, "Undefined parameter '#{key}'"
  end

  @parse_error = options[:parse_error] || Proc.new do |filename, error|
    {}
  end

  validate()
end

Instance Attribute Details

#array_merge_strategy ⇒ Object

Returns the value of attribute array_merge_strategy.



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# File 'lib/nugrant/config.rb', line 12

def array_merge_strategy
  @array_merge_strategy
end

#current_path ⇒ Object (readonly)

Returns the value of attribute current_path.



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# File 'lib/nugrant/config.rb', line 12

def current_path
  @current_path
end

#key_error ⇒ Object (readonly)

Returns the value of attribute key_error.



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# File 'lib/nugrant/config.rb', line 12

def key_error
  @key_error
end

#params_filename ⇒ Object (readonly)

Returns the value of attribute params_filename.



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# File 'lib/nugrant/config.rb', line 12

def params_filename
  @params_filename
end

#params_format ⇒ Object (readonly)

Returns the value of attribute params_format.



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# File 'lib/nugrant/config.rb', line 12

def params_format
  @params_format
end

#parse_error ⇒ Object (readonly)

Returns the value of attribute parse_error.



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# File 'lib/nugrant/config.rb', line 12

def parse_error
  @parse_error
end

#system_path ⇒ Object (readonly)

Returns the value of attribute system_path.



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# File 'lib/nugrant/config.rb', line 12

def system_path
  @system_path
end

#user_path ⇒ Object (readonly)

Returns the value of attribute user_path.



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# File 'lib/nugrant/config.rb', line 12

def user_path
  @user_path
end

Class Method Details

.convert(config = {}) ⇒ Object

Convenience method to easily accept either a hash that will be converted to a Nugrant::Config object or directly a config object.



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# File 'lib/nugrant/config.rb', line 23

def self.convert(config = {})
  return config.kind_of?(Nugrant::Config) ? config : Nugrant::Config.new(config)
end

.default_system_path ⇒ Object

Return the fully expanded path of the system parameters default location that is used in the constructor.



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# File 'lib/nugrant/config.rb', line 39

def self.default_system_path()
  if Config.on_windows?
    return File.expand_path(ENV['PROGRAMDATA'] || ENV['ALLUSERSPROFILE'])
  end

  "/etc"
end

.default_user_path ⇒ Object

Return the fully expanded path of the user parameters default location that is used in the constructor.



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# File 'lib/nugrant/config.rb', line 31

def self.default_user_path()
  File.expand_path("~")
end

.fixup_path(path, default, params_filename) ⇒ Object

Method to fix-up a received path. The fix-up do the follows the following rules:

  1. If the path is callable, call it to get the value.

  2. If value is nil, return default value.

  3. If value is a directory, return path + params_filename to it.

  4. Otherwise, return value

Parameters:

  • path —

    The path parameter received.

  • default —

    The default path to use, can be a directory.

  • params_filename —

    The params filename to append if path is a directory

Returns:

  • The fix-up path following rules defined above.



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# File 'lib/nugrant/config.rb', line 62

def self.fixup_path(path, default, params_filename)
  path = path.call if path.respond_to?(:call)

  path = File.expand_path(path || default)
  path = "#{path}/#{params_filename}" if ::File.directory?(path)

  path
end

.on_windows? ⇒ Boolean

Return true if we are currently on a Windows platform.

Returns:

  • (Boolean) 


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# File 'lib/nugrant/config.rb', line 82

def self.on_windows?()
  (RbConfig::CONFIG['host_os'].downcase =~ /mswin|mingw|cygwin/) != nil
end

.supported_array_merge_strategy(strategy) ⇒ Object 



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# File 'lib/nugrant/config.rb', line 71

def self.supported_array_merge_strategy(strategy)
  SUPPORTED_ARRAY_MERGE_STRATEGIES.include?(strategy)
end

.supported_params_format(format) ⇒ Object 



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# File 'lib/nugrant/config.rb', line 75

def self.supported_params_format(format)
  SUPPORTED_PARAMS_FORMATS.include?(format)
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/nugrant/config.rb', line 152

def ==(other)
  self.class.equal?(other.class) &&
  instance_variables.all? do |variable|
    instance_variable_get(variable) == other.instance_variable_get(variable)
  end
end

#[](key) ⇒ Object 



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# File 'lib/nugrant/config.rb', line 159

def [](key)
  instance_variable_get("@#{key}")
rescue
  nil
end

#merge(other) ⇒ Object 



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# File 'lib/nugrant/config.rb', line 165

def merge(other)
  result = dup()
  result.merge!(other)
end

#merge!(other) ⇒ Object 



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# File 'lib/nugrant/config.rb', line 170

def merge!(other)
  other.instance_variables.each do |variable|
    instance_variable_set(variable, other.instance_variable_get(variable)) if instance_variables.include?(variable)
  end

  self
end

#to_h ⇒ Object Also known as: to_hash 



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# File 'lib/nugrant/config.rb', line 178

def to_h()
  Hash[instance_variables.map do |variable|
    [variable[1..-1].to_sym, instance_variable_get(variable)]
  end]
end

#validate ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/nugrant/config.rb', line 186

def validate()
  raise ArgumentError,
    "Invalid value for :params_format. \
     The format [#{@params_format}] is currently not supported." if not Config.supported_params_format(@params_format)

  raise ArgumentError,
      "Invalid value for :array_merge_strategy. \
       The array merge strategy [#{@array_merge_strategy}] is currently not supported." if not Config.supported_array_merge_strategy(@array_merge_strategy)
end