I'm having some trouble understanding how to clone/duplicate a config object that uses ActiveSupport::Configurable. I'm using the ActiveSupport::Configurable module to create a simple configuration object. In some automated tests, I want to set aside the current configuration, and create a new config object with different value. I have a method called remember_config which just does
module App
class Config
include ActiveSupport::Configurable
def self.remember_config
#previous_config = #config
#config = #config.clone
end
end
end
The trouble occurs when I use it.
App.config.foo = 1
App.config.foo # Returns 1
App.previous_config # Returns nil
App.remember_config
App.config.foo # Still returns 1
App.previous_config.foo # eturns 1
App.config.foo = 2
App.config.foo # Returns 2
App.config.previous_config.foo # Also returns 2, but I'd like it to return 1!
Why does the last line return 2 instead of 1? The #previous_config and config objects have different object_ids. Maybe it's not a clone problem. Maybe it's an issue with the way the ActiveSupport::Configurable magic works.
Try using dup function rather then the clone function.
module App
class Config
include ActiveSupport::Configurable
def self.remember_config
#previous_config = #config
#config = #config.dup
end
end
end
But you can not use class as singleton class.
Related
So far I always used "puts" to add custom logging infos to my code. But now it is kind of a pain. When I run rspec for exemple I'm not interested in all the verbose that I added with puts. So I installed the "logging and logging-rails gem" because its installation is real fast and satisfying.
It works well when I call logger from models and controller, but not when I'm using logger inside libraries. I get that error : NameError - undefined local variable or method `logger' for CustomLib:Class.
The easiest thing I succeeded is to call 'Rails.logger' instead of just 'logger'. But in that way in my logfile, the class referring to that line will be 'Rails' but I want 'CustomLib'. For models and controller the right classname is displayed without any intervention from myself.
# config/environnement/test.rb
# Set the logging destination(s)
config.log_to = %w[stdout]
config.log_level = :info
# Show the logging configuration on STDOUT
config.show_log_configuration = false
# lib/custom_lib.rb
class CustomLib
def initialize
Rails.logger.info 'foo'
end
end
When I will use or test my customlib class I'll get :
[2019-06-21T16:26:41] INFO Rails : foo
Instead I would like to see :
[2019-06-21T16:26:41] INFO CustomLib : foo
I'm a bit lost in all that log management in rails, I have no idea what to try next to reach that goal...
Edit
When I put a byebug just before the "logger.info 'foo' " line and enter into it via 'step', I got two different results if whether I'm in a model/controller or a custom lib.
# In custom lib, step enters this file "gems/logging-2.2.2/lib/logging/logger.rb"
# And Rails.logger returns an object like this one beloow
Logging::Logger:0x000055a2182f8f40
#name="Rails",
#parent=#<Logging::RootLogger:0x000055a2182e7ee8
#name="root",
#level=1>,
# In model/controller, step enters this file "gems/logging-rails-0.6.0/lib/logging/rails/mixin.rb"
# And Rails.logger returns an object like this one beloow
Logging::Logger:0x0000557aed75d7b8
#name="Controller",
#parent=#<Logging::RootLogger:0x0000557aedfcf630
#name="root",
#level=0>,
At the end I found a better way, I just need to include Logging.globally on top of the module where I want that behavior:
# lib/custom_lib.rb
class CustomLib
include Logging.globally
def initialize
logger.info 'foo'
end
end
The Rails in the log line is the progname of the logger. You could create a new logger that sets the progname to 'CustomLib'with (say) Rails.logger.clone.tap {|l| l.progname = 'CustomLib' }, but that isn't really the purpose of progname, which is to specify the name of the program, not the name of a class.
You could instead include the class name in the log line:
Rails.logger.info "[#{self.class}] - some message"
Or, for a bit more effort, you could define your own formatter. Here's one with a convenience method for wrapping an existing logger:
class ClassNameFormatter
def self.wrap_logger(klass, logger)
logger.clone.tap { |l| l.formatter = new(klass, logger.formatter) }
end
def initialize(klass, formatter=nil)
#klass = klass
#formatter = formatter ||= Logger::Formatter.new
end
def call(severity, timestamp, progname, msg)
#formatter.call severity, timestamp, progname, "[#{#klass.name}] - #{msg}"
end
end
To use it:
class CustomLib
def initialize
#logger = ClassNameFormatter.wrap_logger self.class, Rails.logger
end
def call
#logger.info 'test log please ignore'
end
end
Suppose I need to parse some configuration to instanciate some Service Singletons (that could be used with or without Rails).
A sample code example:
#services/my_service.rb
module MyService
#config = nil
def self.load_config(config)
#config = config
end
When using with Rail (or Capistrano, SInatra, etc.) I would use an initializer to boot up the service
#initializers/svc.rb
MyService.load_config(Rails.application.secrets.my_service.credentials)
But when used specifically with Rails, on every rails console restart!, this #config variable is cleared which is a problem...
Are there
after-reload! hooks that I could use to re-run the initializer ?
other types of variables that would be preserved during a restart!
that I could use here ?
You could define config method as:
def config
#config ||= Rails.application.secrets.my_service.credentials
end
And call this method instead of #config, so when the config variable is unset, it will be set again, otherwise it will return the value.
Seeing that people are still reading this, here is implementation I ended up with
# config/initializers/0_service_activation.rb
# Activation done at the end of file
module ServiceActivation
def self.with_reload
ActiveSupport::Reloader.to_prepare do
yield
end
end
module Slack
def self.service
::SlackConnector
end
def self.should_be_activated?
Utility.production? ||
Utility.staging? ||
(
Utility.development? &&
ENV['ENABLE_SLACK'] == 'true'
)
end
def self.activate
slack = service
slack.webhook = Rails.application.secrets.slack&.dig(:slack_webhooks)
Rails.application.secrets&.dig(:slack, :intercept_channel).try do |channel|
slack.intercept_channel = channel if channel.present?
end
slack.activate
slack
end
end
[
ServiceActivation::Intercom,
ServiceActivation::Slack,
ServiceActivation::Google
] .each do |activator|
ServiceActivation.with_reload do
activator.activate if activator.should_be_activated?
activator.service.status_report
end
end
I am not showing my connector class SlackConnector, but basically you can probably guess the interface from the way it is called. You need to set the webhook url, and do other stuff. The implementation is decoupled, so it's possible to use the same SlackConnector in Rails and in Capistrano for deployment, so it's basically in the lib/ folder
I'm trying to create a module that will be included in many different classes. It needs to record the caller's path to the class file
so I can reference the path in later code. This code tries to add a method to the calling class, but fails because it just returns the current value of ##x.
# /home/eric/FindMe.rb
class FindMe
include GladeGUI
end
# /home/eric/GladeGUI.rb
module GladeGUI
def self.included(obj)
##x, = caller[0].partition(":") # this works ##x = "/home/eric/FindMe.rb"
obj.class_eval do
def my_class_file_path
return ????? # I want to return "/home/eric/FindMe.rb"
end
end
end
end
The GladeGUI module will be "included" in many different classes, so I can't just add code to the calling class. I need a way to make ##x compile into a constant value, so the method stored in the class looks like this:
def my_class_file_path
return "/home/eric/FindMe.rb"
end
How do I convert a variable to a constant in code?
Thanks.
It seems like you don't actually need it to be a "constant" - you just need some way to make the method return the correct value all the time and not allow other code to come along and change the value (with the current ##x solution, someone can just modify ##x and it will break)
The solution is to store the data in a local variable instead of a class or instance variable, and then access that local variable via a closure.
No other code will have scope to 'see' the local variable and thus it cannot be changed.
But then the problem becomes that when you use def inside a class_eval, the scope of the caller isn't captured, so the code can't see your local variable. You can use define_method instead
Here's an example
# /home/eric/GladeGUI.rb
module GladeGUI
def self.included(obj)
caller_file_path = caller[0].split(":").first
obj.class_eval do
define_method :my_class_file_path do
return caller_file_path
end
end
end
end
# /home/eric/FindMe.rb
class FindMe
include GladeGUI
end
puts FindMe.new.my_class_file_path # prints the correct path
But - what if you want my_class_file_path to be a class method rather than an instance method - use define_singleton_method instead:
module GladeGUI
def self.included(obj)
caller_file_path = caller[0].split(":").first
obj.class_eval do
define_singleton_method :my_class_file_path do
return caller_file_path
end
end
end
end
...
puts FindMe.my_class_file_path
Interesting side note: This is how you can fake "private variables" in javascript :-)
I have a setup in the lib directory like so:
lib/
copy_process.rb
copy_process/
processor.rb
The copy_process.rb and processor.rb contain the module definition CopyProcess. The copy_process.rb defines the CopyFile class as well:
module CopyProcess
class CopyFile
end
end
The processor.rb is structured like so:
module CopyProcess
class Processer
end
end
In one of its methods, it creates a new copy file object:
def append_file_if_valid(file_contents, headers, files, file_name)
unless headers
raise "Headers not found"
else
files << CopyProcess::CopyFile.new()
end
end
When I used these files as part of a command line ruby program, it worked fine. However, i started putting it into a rails app, and I have written cucumber/capybara tests to hit the buttons and so forth where this is used. I initialize a Processor object from one of my AR models, and call the above method a few times. It cannot seem to find the CopyFile class, even though I have the following code in my application.rb
config.autoload_paths += %W(#{config.root}/lib)
config.autoload_paths += Dir["#{config.root}/lib/**/"]
Any ideas?
===============================================================
Edit Above was solved by extracting the copy file class into it's own file under lib.
I now have another issue:
The CopyFile class refers to module-level helper methods that sit in lib/copy_process.rb, like so:
module CopyProcess
# Gets the index of a value inside an array of the given array
def get_inner_index(value, arr)
idx = nil
arr.each_with_index do |e, i|
if e[0] == value
idx = i
end
end
return idx
end
def includes_inner?(value, arr)
bool = false
arr.each { |e| bool = true if e[0] == value }
return bool
end
# Encloses the string in double quotes, in case it contains a comma
# #param [String] - the string to enclose
# #return [String]
def enclose(string)
string = string.gsub(/\u2019/, '’')
if string.index(',')
return "\"#{string}\""
else
return string
end
end
end
When I run my cucumber tests, i get the following error:
undefined method `includes_inner?' for CopyProcess:Module (NoMethodError)
./lib/copy_process/copy_file.rb:64:in `set_element_name_and_counter'
Which refers to this method here:
def set_element_name_and_counter(element_names, name)
if !CopyProcess::includes_inner?(name, element_names)
element_names << [name, 1]
else
# if it's in the array already, find it and increment the counter
current_element = element_names[CopyProcess::get_inner_index(name, element_names)]
element_names[CopyProcess::get_inner_index(name, element_names)] = [current_element[0], current_element[1]+1]
end
element_names
end
I also tried moving the copy_file.rb and other files in the lib/copy_process/ directory up a level into the lib directory. I then received the following error:
Expected /Users/aaronmcleod/Documents/work/copy_process/lib/copy_file.rb to define CopyFile (LoadError)
./lib/processor.rb:48:in `append_file_if_valid'
The line that the error states creates an instance of CopyFile. I guess rails doesn't like loading the files in that fashion, and for the former setup, I think the copy_file.rb is having issues loading the rest of the module. I tried requiring it and so forth, but no luck. You can also find my most recent code here: https://github.com/agmcleod/Copy-Process/tree/rails
First config.autoload_paths += %W(#{config.root}/lib) should be sufficient. This tells rails to start looking for properly structured files at /lib.
Second, I think that you're running into issues because CopyFile isn't where rails expects it to be. As far as I know your setup 'should' work but have you tried seperating CopyFile out into its own file under the copy_process folder? My guess is that since the copy_process folder exists, it is expecting all CopyProcess::* classes to be defined there instead of the copy_process.rb.
EDIT: You may consider opening another question, but the second half of your question is a different problem entirely.
You define methods in your module like so,
module X
def method_one
puts "hi"
end
end
Methods of this form are instance methods on the module, and they have very special restrictions. For instance, you can not access them from outside the module definition (I'm skeptical how these worked previously). Executing the above gives
> X::method_one
NoMethodError: undefined method `method_one' for X:Module
If you want to access these methods from other scopes you have a few options.
Use Class Methods
module X
def self.method_one
puts "hi"
end
end
X::hi #=> "hi"
Use Mixins
module X
module Helpers
def method_one
puts "hi"
end
end
end
class CopyFile
include X::Helpers
def some_method
method_one #=> "hi"
self.method_one #=> "hi"
end
end
i am trying to create my first rails plugin, and i want it to be configurable, that is to say, i want to be able to set a variable in the environment.rb file or something.
UPDATE: i'm trying to do something like what's done here: http://soakedandsoaped.com/articles/read/exception-notifier-ruby-on-rails-plugin. i have tried mimicking their code, but i can't get it working.
i have the plugin working with the value hard-coded, but everything i have tried so far for making it configurable hasn't worked.
Here's some of the code:
#vendor/plugin/markup/lib/markup_helper.rb
module MarkupHelper
def stylesheet_cache_link_tag(*sources)
cache = assests_cache_dir ? assests_cache_dir : ""
options = sources.extract_options!.stringify_keys
cached_name = options.delete("cached_name")
stylesheet_link_tag(sources, :cache=> File.join(cache, cached_name))
end
def javascript_cache_include_tag(*sources)
cache = assests_cache_dir ? assests_cache_dir : ""
options = sources.extract_options!.stringify_keys
cached_name = options.delete("cached_name")
javascript_include_tag(sources, :cache=> File.join(cache, cached_name))
end
end
#something like the following in config/environment.rb or probably config/environments/production.rb
MarkupConfig.assests_cache_dir = "cache"
i want assests_cache_dir to default to "cache" but be able to set in an environment config file. i have googled a long time on this, and can't find anything discussing this. How can i accomplish this?
module MarkupHelper
mattr_accessor :assets_cache_dir
self.assets_cache_dir = "cache"
def assets_cache_dir
MarkupHelper.assets_cache_dir
end
end
Then in environment.rb (or development.rb/test.rb/production.rb if you want different values for each environment):
MarkupHelper.assets_cache_dir = "my-value"
Although the approach used by tomafro is quite easy to use, another approach is to use a database.yml-style configuration file that can be split according to environments:
module MyPlugin
class Configuration
# == Constants ==========================================================
CONFIG_FILES = [
"#{RAILS_ROOT}/config/myplugin.yml",
"#{RAILS_ROOT}/config/myplugin.yaml"
].freeze
DEFAULT_CONFIGURATION = {
:url => DEFAULT_HOSTNAME
}.freeze
# == Class Methods ======================================================
# :nodoc:
def self.config_file_found
CONFIG_FILES.find do |path|
File.exist?(path)
end
end
# Returns the default path to the configuration file
def self.default_path
config_file_found or CONFIG_FILES.first
end
# == Instance Methods ===================================================
# Creates a new MyPlugin::Configuration instance by reading from the
# configuration file.
# +env+ The Rails environment to load
def initialize(env)
config_file = self.class.config_file_found
#env_config = DEFAULT_CONFIGURATION
if (#config = (config_file and YAML.load(File.open(config_file))))
[ #config['defaults'], #config[env] ].each do |options|
if (options)
#env_config = #env_config.merge(options.symbolize_keys)
end
end
end
end
# Will return +true+ if a configuration file was found and loaded, or
# +false+ otherwise.
def exists?
#env_config != DEFAULT_CONFIGURATION
end
# Returns a particular configuration option.
def [](key)
#env_config[key.to_sym]
end
end
def self.config
#config ||= Configuration.new(Rails.env)
end
end
You would use this as:
settting = MyPlugin.config[:param_name]
You can also write utility methods to fetch particular values, or use OpenStruct instead of a configuration Hash. This is posted merely as an example of another design pattern.