I’ve been working on a pet project using Sinatra and Unicorn (doing some long-polling stuff, so I needed to support multiple connections even in dev). Unfortunately, this combination makes code reloading tricky to tackle, as it rules out shotgun entirely, and seems to also bust Sinatra::Reloader.

After a couple hours of HUPping unicorns manually, I decided that I needed a more robust solution. Some digging led me to the FSSM gem by ttilley. This library will watch your file system for events and runs a registered callback when they occur. A few minutes of hacking and my reloading woes are solved!

#!/usr/bin/env ruby -wKU

require 'rubygems'
require 'fssm'

puts "Monitoring #{File.expand_path(File.dirname(__FILE__))} for changes..."
FSSM.monitor(File.dirname(__FILE__), ['**/*.rb', '**/*.ru', '**/*.yml']) do
  update { system "kill -HUP `cat pids/unicorn.pid`" }
end

exit 0

My project revolved around data collection, and I pretty quickly ran into the need to see what I was actually shoving into the database. After 10 minutes and only ~50 lines, I came up with a Sinatra backed Redis viewer. See the code below, or check out my gist on Github!

# app.rb
require 'rubygems'
require 'haml'
require 'sinatra'
require 'redis'

helpers do
  def redis
    @redis ||= Redis.new
  end
end

get "/" do
  @keys = redis.keys("*")
  haml :index
end

get "/:key" do
  @key = params[:key]
  @data = case redis.type(@key)
  when "string"
    Array(redis[@key])
  when "list"
    redis.lrange(@key, 0, -1)
  when "set"
    redis.set_members(@key)
  else
    []
  end
  haml :show
end

# views/index.haml
%html
%body
  %h1 Current Keys
  %ul
    - @keys.each do |key|
      %li
        %a{:href => "/#{key}"}= key

# views/show.haml
%html
%body
  %h1= "Data stored in '#{@key}'"
  %ul
    -@data.each do |data|
      %li
        %p= data