While practicing Ruby, I decided it would be nice to have some sort of state machine gem to help me manage the application state of a basic Ruby app (not using Rails).
I didn't find one, or didn't know where to look. So I wrote one.
The gem's name is gk-application, it's on rubygems and the GitHub repo is here: https://github.com/gregkrsak/gk-application
Basically, an application is an instance of GK::Application, which can then be in one of four states: :stopped, :starting, :running or :stopping.
The application's code lives in the event handlers attached to each state. To start the app, set its state attribute to :starting.
If you have the gem installed and would prefer to have a project template built for you, simply use one of the following methods:
Using ruby:
ruby -e 'require "gk-application"' -e 'GK::Application.new.project'
Using irb:
$ irb
irb(main):001:0> require 'gk-application'
=> true
irb(main):002:0> GK::Application.new.project
=> nil
irb(main):003:0> quit
Either of which will generate a file named my_app.rb in the current directory, containing:
#!/usr/bin/env ruby
require 'gk-application'
my_app = GK::Application.new
my_app.on_starting = Proc.new do
puts 'Starting.'
my_app.state = :running
end
my_app.on_running = Proc.new do
puts 'Running.'
my_app.state = :stopping
end
my_app.on_stopping = Proc.new do
puts 'Stopping.'
my_app.state = :stopped
end
my_app.on_stopped = Proc.new do
puts 'Stopped.'
end
my_app.state = :starting
Which should get you started. Thanks for reading! Feel free to contribute to the code.
Related
I'd like to extend the default console application that is built as standard with bundle gem by applying some of the IRB config options.
Looking at the documentation, I can see that it should be possible for instance to change the prompt, and this works fine on an interactive session. For example I can play with the displayed prompt like this:
2.1.4 :001 > conf.prompt_mode=:SIMPLE
=> :SIMPLE
>>
?> conf.prompt_mode=:DEFAULT
=> :DEFAULT
irb(main):004:0>
However, I cannot find how to translate this into syntax for use in the console app. For example this script:
require 'irb'
IRB.conf[:PROMPT_MODE] = :SIMPLE
IRB.start
Just starts with the generic configured prompt:
2.1.4 :001 >
I have spent some time trying to find an example use of IRB for a custom repl without loading global defaults, but not found anything I can copy from.
I can see that the undocumented method IRB.setup has something to do with this, it is setting all the config somehow. Is my only option to write my own version of IRB.start that applies my desired config after calling IRB.setup, or is there support for what I want to do built-in but not documented in standard location?
E.g. the following works, but I feel it's a bit heavy handed extending IRB module this way (and also prone to failing if IRB internals change).
require 'irb'
def IRB.custom_start custom_conf = {}
STDOUT.sync = true
IRB.setup(nil)
custom_conf.each do |k,v|
IRB.conf[k] = v
end
if #CONF[:SCRIPT]
irb = IRB::Irb.new(nil, #CONF[:SCRIPT])
else
irb = IRB::Irb.new
end
#CONF[:IRB_RC].call(irb.context) if #CONF[:IRB_RC]
#CONF[:MAIN_CONTEXT] = irb.context
trap("SIGINT") do
irb.signal_handle
end
begin
catch(:IRB_EXIT) do
irb.eval_input
end
ensure
irb_at_exit
end
end
IRB.custom_start :PROMPT_MODE => :SIMPLE
You can apply custom configurations in two ways.
The first one is to use irbrc file. It may be tricky in building console application (calling IRB.start from the ruby file instead of irb from the console).
The second one is the approach that you have described in the post. You can write your own IRB::start method based on the original one. There are exactly the same potential issues as in using undocumented API - it can break in the future with newer versions of irb.
You should think if you really need to build a console application on the top of irb. For example you can solve this problem using Pry. It allows to define configuration before starting interactive session.
require 'irb'
IRB.conf[:PROMPT_MODE] = :SIMPLE
IRB.start
The approach above doesn't work because conf[:PROMPT_MODE] gets over-riden in a method called IRB.init_config here
When IRB.start is called, it calls IRB.setup which in turn calls the method IRB.init_config -- which over-rides conf[:PROMPT_MODE] setting.
Here is one approach which solves the problem (relies on internal knowledge of the implementation).
require 'irb'
module IRB
singleton_class.send(:alias_method, :old_setup, :setup)
def IRB.setup(ap_path)
IRB.old_setup(ap_path)
conf[:PROMPT_MODE] = :SIMPLE
end
end
IRB.start
I would like to have a clear function in my irb console, but there isn't one. Here's what I type in every time I load irb from the terminal:
def cls
system 'clear'
end
It's not real hard to type this each time a load irb, but it would certainly be nice to have this function load automatically when irb starts.
Is it possible to do this?
When irb is starting up, it looks for the file .irbrc in your home directory. If the file exists, it evaluates it. So this file is the perfect place to add some generic stuff to irb...
For inspiration, mine looks like this:
require 'rubygems'
require 'pp'
require 'irb/ext/save-history'
# add $HOME/lib to the load path
$: << '~/lib'
IRB.conf[:AUTO_INDENT] = true
IRB.conf[:SAVE_HISTORY] = 1000
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb_history"
def real_instance_methods_of(klass)
klass.instance_methods - ((klass.ancestors - [klass]).map(&:instance_methods).flatten)
end
class Class
def instance_methods_defined_here
real_instance_methods_of self
end
end
# more stuff...
# ...
EDIT: I just noticed the comment by Dave Newton now; he already pointed out the .irbrc solution...
on a mac just hit CMD + K to clear the screen
I have a Rakefile which, on my own-built Ruby 1.9.3 installation, correctly outputs the Unix shell equivalent when I use a FileUtils method such as cp, mkdir etc.
However, on the stock Ruby that ships with Mac OS X (specifically 10.5), which is version 1.8.6, they don't do this.
I'd like them to output the commands as they're performed. Is there a way to enable this in OS X's 1.8.6 Ruby, short of adding :verbose => true to every call? (Which may not even work.)
The Rakefile in question is: https://github.com/dpkendal/tools-osx/blob/master/Rakefile
That doesn't make sense. 1.9.3 should not do :verbose unless explicitly told to do so. You can look at the implementation of mkdir in the 1.9.3 lib for example:
def mkdir(list, options = {})
fu_check_options options, OPT_TABLE['mkdir']
list = fu_list(list)
fu_output_message "mkdir #{options[:mode] ? ('-m %03o ' % options[:mode]) : ''}#{list.join ' '}" if options[:verbose]
return if options[:noop]
list.each do |dir|
fu_mkdir dir, options[:mode]
end
end
There you can see that the message is not generated unless the :verbose option is explicitly supplied.
However to enable :verbose across all FileUtils methods you can simply include FileUtils::Verbose into your namespace. This works in both 1.8 and 1.9 ruby:
irb(main):001:0> RUBY_VERSION
=> "1.8.7"
irb(main):002:0> include FileUtils::Verbose
=> Object
irb(main):003:0> mkdir 'fooof'
mkdir fooof
=> ["fooof"]
BTW, it might be that Rake already does this in 1.9.3, which would explain why it does what it does in 1.9.3 and not in 1.8.6. I did not check this, but that's the only explanation I can think of.
Rake provides its own FileUtils extension called Rake::FileUtilsExt. This module has a verbose flag. To activate it simply add this to the top of the Rakefile:
Rake::FileUtilsExt.verbose(true)
It seems that in Sinatra all route handlers are being written into a single file, if I understand right it acts as a one large/small controller. Is there any way to split it into separate independent files, so when let's say somebody calls "/" - one action is executed, and if smth like "/posts/2" is received then another action - similar logic that is applied in PHP?
Here is a basic template for Sinatra apps that I use. (My larger apps have 200+ files broken out like this, not counting vendor'd gems, covering 75-100 explicit routes. Some of these routes are Regexp routes covering an additional 50+ route patterns.) When using Thin, you run an app like this using:
thin -R config.ru start
Edit: I'm now maintaining my own Monk skeleton based on the below called Riblits. To use it to copy my template as the basis for your own projects:
# Before creating your project
monk add riblits git://github.com/Phrogz/riblits.git
# Inside your empty project directory
monk init -s riblits
File Layout:
config.ru
app.rb
helpers/
init.rb
partials.rb
models/
init.rb
user.rb
routes/
init.rb
login.rb
main.rb
views/
layout.haml
login.haml
main.haml
config.ru
root = ::File.dirname(__FILE__)
require ::File.join( root, 'app' )
run MyApp.new
app.rb
# encoding: utf-8
require 'sinatra'
require 'haml'
class MyApp < Sinatra::Application
enable :sessions
configure :production do
set :haml, { :ugly=>true }
set :clean_trace, true
end
configure :development do
# ...
end
helpers do
include Rack::Utils
alias_method :h, :escape_html
end
end
require_relative 'models/init'
require_relative 'helpers/init'
require_relative 'routes/init'
helpers/init.rb
# encoding: utf-8
require_relative 'partials'
MyApp.helpers PartialPartials
require_relative 'nicebytes'
MyApp.helpers NiceBytes
helpers/partials.rb
# encoding: utf-8
module PartialPartials
def spoof_request(uri,env_modifications={})
call(env.merge("PATH_INFO" => uri).merge(env_modifications)).last.join
end
def partial( page, variables={} )
haml page, {layout:false}, variables
end
end
helpers/nicebytes.rb
# encoding: utf-8
module NiceBytes
K = 2.0**10
M = 2.0**20
G = 2.0**30
T = 2.0**40
def nice_bytes( bytes, max_digits=3 )
value, suffix, precision = case bytes
when 0...K
[ bytes, 'B', 0 ]
else
value, suffix = case bytes
when K...M then [ bytes / K, 'kiB' ]
when M...G then [ bytes / M, 'MiB' ]
when G...T then [ bytes / G, 'GiB' ]
else [ bytes / T, 'TiB' ]
end
used_digits = case value
when 0...10 then 1
when 10...100 then 2
when 100...1000 then 3
else 4
end
leftover_digits = max_digits - used_digits
[ value, suffix, leftover_digits > 0 ? leftover_digits : 0 ]
end
"%.#{precision}f#{suffix}" % value
end
module_function :nice_bytes # Allow NiceBytes.nice_bytes outside of Sinatra
end
models/init.rb
# encoding: utf-8
require 'sequel'
DB = Sequel.postgres 'dbname', user:'bduser', password:'dbpass', host:'localhost'
DB << "SET CLIENT_ENCODING TO 'UTF8';"
require_relative 'users'
models/user.rb
# encoding: utf-8
class User < Sequel::Model
# ...
end
routes/init.rb
# encoding: utf-8
require_relative 'login'
require_relative 'main'
routes/login.rb
# encoding: utf-8
class MyApp < Sinatra::Application
get "/login" do
#title = "Login"
haml :login
end
post "/login" do
# Define your own check_login
if user = check_login
session[ :user ] = user.pk
redirect '/'
else
redirect '/login'
end
end
get "/logout" do
session[:user] = session[:pass] = nil
redirect '/'
end
end
routes/main.rb
# encoding: utf-8
class MyApp < Sinatra::Application
get "/" do
#title = "Welcome to MyApp"
haml :main
end
end
views/layout.haml
!!! XML
!!! 1.1
%html(xmlns="http://www.w3.org/1999/xhtml")
%head
%title= #title
%link(rel="icon" type="image/png" href="/favicon.png")
%meta(http-equiv="X-UA-Compatible" content="IE=8")
%meta(http-equiv="Content-Script-Type" content="text/javascript" )
%meta(http-equiv="Content-Style-Type" content="text/css" )
%meta(http-equiv="Content-Type" content="text/html; charset=utf-8" )
%meta(http-equiv="expires" content="0" )
%meta(name="author" content="MeWho")
%body{id:#action}
%h1= #title
#content= yield
Absolutely. To see an example of this I recommend downloading the Monk gem, described here:
https://github.com/monkrb/monk
You can 'gem install' it via rubygems.org. Once you have the gem, generate a sample app using the instructions linked above.
Note that you don't have to use Monk for your actual development unless you want to (in fact I think it may not be current). The point is to see how you can easily structure your app in the MVC style (with separate controller-like route files) if you want to.
It's pretty simple if you look at how Monk handles it, mostly a matter of requiring files in separate directories, something like (you'll have to define root_path):
Dir[root_path("app/**/*.rb")].each do |file|
require file
end
Do a Google search for "Sinatra boilerplate" to get some ideas for how others are laying out their Sinatra applications. From that you can probably find one that suits your needs or simply make your own. It's not too hard to do. As you develop more Sinatra apps, you can add to your boilerplate.
Here's what I made and use for all of my projects:
https://github.com/rziehl/sinatra-boilerplate
I know this is an old query but I still can't believe no one mentioned Padrino You can use it as a framework on top of Sinatra, or piecemeal adding only the gems that interest you. It kicks ten buttloads of ass!
The key for modularity on Sinatra for larger projects is learning to use the underlying tools.
SitePoint has a very good tutorial from where you can see modular Sinatra apps and helpers. However you should pay special attention to one important detail. You keep multiple Sinatra apps and mount them with Rackup. Once you know how to write a basic app look at the config.ru file of that tutorial and observe how they mount independent Sinatra apps.
Once you learn to run Sinatra with Rack a whole new world of modularity strategies will open up. This obviously invites to try something really useful: now you can rely on having individual Gems for each sub application, what might enable you to easily version your modules.
Do not underestimate the power of using gem-modules for your app. You can easily test experimental changes in a well delimited environment and easily deploy them. Equally easy to revert back if something goes wrong.
There are a thousand ways to organize your code, so it would not hurt trying to get a layout similar to Rails. However there are also some great posts about how to customize your own structure. That post covers other frequent needs of most web developers.
If you have the time, I encourage you to learn more about Rack, the common ground for any Ruby based web application. It might have a far lesser impact in how you do your work, but there are always certain tasks that most people do on their apps that fits better as a Rack middleware.
My approach to host different projects on the same site is to use sinatra/namespace in such way:
server.rb
require "sinatra"
require "sinatra/namespace"
if [ENV["LOGNAME"], ENV["USER"]] == [nil, "naki"]
require "sinatra/reloader"
register Sinatra::Reloader
set :port, 8719
else
set :environment, :production
end
for server in Dir.glob "server_*.rb"
require_relative server
end
get "/" do
"this route is useless"
end
server_someproject.rb
module SomeProject
def self.foo bar
...
end
...
end
namespace "/someproject" do
set :views, settings.root
get "" do
redirect request.env["REQUEST_PATH"] + "/"
end
get "/" do
haml :view_someproject
end
post "/foo" do
...
SomeProject.foo ...
end
end
view_someproject.haml
!!!
%html
...
Another detail about subprojects I used was to add their names, description and routes to some kind of global variable, that is used by "/" to make a guide homepage, but I don't have a snippet right now.
Reading the docs here:
Sinatra Extensions
It appears that Sinatra allows you to decompose your application into Ruby Modules, which can be pulled in through the Sinatra "register" method or "helpers" methods, like so:
helpers.rb
require 'sinatra/base'
module Sinatra
module Sample
module Helpers
def require_logged_in()
redirect('/login') unless session[:authenticated]
end
end
end
end
routing/foos.rb
require 'sinatra/base'
module Sinatra
module Sample
module Routing
module Foos
def self.registered(app)
app.get '/foos/:id' do
# invoke a helper
require_logged_in
# load a foo, or whatever
erb :foos_view, :locals => { :foo => some_loaded_foo }
end
end
end
end
end
end
app.rb
#!/usr/bin/env ruby
require 'sinatra'
require_relative 'routing/foos'
class SampleApp < Sinatra::Base
helpers Sinatra::Sample::Helpers
register Sinatra::Sample::Routing::Foos
end
When Monk didn't work for me, I started working on templates myself.
If you think about it, there is nothing special about tying up a set of files. The monk philosophy was explained to me early in 2011 during RedDotRubyConf and they have specifically told me that it's really optional to use it especially now that it's hardly maintained.
This is a good start for those who want to use ActiveRecord:
Simple Sinatra MVC
https://github.com/katgironpe/simple-sinatra-mvc
Can I drop to an IRB prompt from a running Ruby script?
I want to run a script, but then have it give me an IRB prompt at a point in the program with the current state of the program, but not just by running rdebug and having a breakpoint.
Pry (an IRB alternative) also lets you do this, in fact it was designed from the ground up for exactly this use case :)
It's as easy as putting binding.pry at the point you want to start the session:
require 'pry'
x = 10
binding.pry
And inside the session:
pry(main)> puts x
=> 10
Check out the website: http://pry.github.com
Pry let's you:
drop into a session at any point in your code
view method source code
view method documentation (not using RI so you dont have to pre-generate it)
pop in and out of different contexts
syntax highlighting
gist integration
view and replay history
open editors to edit methods using edit obj.my_method syntax
A tonne more great and original features
you can use ruby-debug to get access to irb
require 'rubygems'
require 'ruby-debug'
x = 23
puts "welcome"
debugger
puts "end"
when program reaches debugger you will get access to irb.
apparently it requires a chunk of code to drop into irb.
Here's the link (seems to work well).
http://jameskilton.com/2009/04/02/embedding-irb-into-your-ruby-application
require 'irb'
module IRB
def self.start_session(binding) # call this method to drop into irb
unless #__initialized
args = ARGV
ARGV.replace(ARGV.dup)
IRB.setup(nil)
ARGV.replace(args)
#__initialized = true
end
workspace = WorkSpace.new(binding)
irb = Irb.new(workspace)
#CONF[:IRB_RC].call(irb.context) if #CONF[:IRB_RC]
#CONF[:MAIN_CONTEXT] = irb.context
catch(:IRB_EXIT) do
irb.eval_input
end
end
end
This feature is available from Ruby 2.4. You can just use binding.irb
E.g.
require 'irb'
a = 10
binding.irb
puts a
If you run above code, you will get irb console, so that you can inspect values of local variables and anything else that is in scope.
Source: http://blog.redpanthers.co/new-binding-irb-introduced-ruby-2-4/
Ruby commit: https://github.com/ruby/ruby/commit/493e48897421d176a8faf0f0820323d79ecdf94a
Just add this line to where you want the breakpoint:
require 'ruby-debug';debugger
but i suggest use pry instead of irb, which is super handy, insert the following line instead:
require 'pry'; binding.pry
I'm quite late to the game but if you're loading a script from within irb/pry already, a simple raise also works to pop you back out to the irb/pry prompt. I use this quite often when writing one off scripts within the rails console.