Ruby Sinatra web apps with background work threads

In Java-land, I have often used the pattern of writing a servlet with an init() method that starts up one or more background work threads. Then while my web application is handling HTTP requests the background threads can be doing work like fetching RSS feeds for display in the web app, perform periodic maintenance like flushing old data from a database, etc. This is a simple pattern that is robust and easy to implement with a few extra lines of Java code and an extra servlet definition in a web.xml file.

In Ruby-land this pattern is even simpler to implement:

require 'rubygems'
require 'sinatra'

$sum = 0

Thread.new do # trivial example work thread
  while true do
     sleep 0.12
     $sum += 1
  end
end

get '/' do
  "Testing background work thread: sum is #{$sum}"
end
While the main thread is waiting for HTTP requests the background thread can do any other work. This works fine with Ruby 1.8.7 or any 1.9.*, but I would run this in JRuby for a long-running production app since JRuby uses the Java Thread class.

Comments

  1. Unknown5:19 AM

    Hi Mark
    That source code is not working my source code..

    require 'sinatra'
    require 'rest_client'
    require 'data_mapper'
    require 'nokogiri'
    require 'json'
    require 'open-uri'
    require 'sinatra/flash'
    require 'will_paginate'
    require 'will_paginate/array'
    require 'date'
    require 'time'
    require 'thread'

    DataMapper::setup(:default, "sqlite3://#{File.dirname(__FILE__)}/a.db")

    class Ladder_data
    include DataMapper::Resource
    property :id, Serial
    property :time, String
    property :times2, String
    property :start_point, String
    property :ladder_type, String
    property :answer, String

    validates_uniqueness_of :times2
    end

    DataMapper.finalize
    Ladder_data.auto_upgrade!
    Thread.new do # trivial example work thread
    while true do
    $t=Time.now
    $t=$t.min
    $t=$t%2

    if $t==0

    a = JSON.parse( open("http://named.com/page/ladder/ajax/result.php").read )
    b=a['times']
    z=a['times2']
    ladder = Ladder_data.new
    ladder.time = b
    ladder.times2 = z

    c=a['start_point']
    if c == 'first'
    ladder.start_point = '왼쪽'
    else
    ladder.start_point= '오른쪽'
    end

    d=a['ladder_type']

    if d == 'type1'
    ladder.ladder_type ='3'
    else
    ladder.ladder_type = '4'
    end

    e=a['answer']
    if e == 'EVEN'
    ladder.answer='짝'
    else
    ladder.answer= '홀'
    end
    ladder.save

    end
    end
    end


    this is my source code.

    ReplyDelete

Post a Comment

Popular posts from this blog

My Dad's work with Robert Oppenheimer and Edward Teller

Robert Oppenheimer and Edward Teller facilitated my Dad getting a professorship at UC Berkeley when I was 3 years old. Oppenheimer left Berkeley but Teller was a good friend of my father and I remember him being in our home. Three weeks ago, my wife and I were just leaving to see the new Oppenheimer movie when my Dad called. He mentioned that when I was in grade school he was invited to give a talk at Princeton. After his talk Oppenheimer talked with my Dad and invited him to have dinner at his house. My Dad said Oppenheimer was not well (I think he died of throat cancer soon afterwards) but his wife Kitty carried the conversation. My Dad, Ken Watson, passed away 10 days ago on August 18, 2023.
Read more

I am moving back to the Google platform, less excited by what Apple is offering

I have been been playing with the Apple Intelligence beta’s in iPadOS and macOS and while I like the direction Apple is heading I am getting more use from Google’s Gemini, both for general analysis of very large input contexts, as well as effective integration my content in Gmail, Google Calendar, and Google Docs. While I find the latest Pixel phone to be compelling, I will stick with Apple hardware since I don’t want to take the time to move my data and general workflow to a Pixel phone. The iPhone is the strongest lock-in that Apple has on me because of the time investment to change. The main reason I am feeling less interested in the Apple ecosystem and platform is that I believe that our present day work flows are intimately wrapped up with the effective use of LLMs, and it is crazy to limit oneself to just one or two vendors. I rely on running local models on Ollama, super fast APIs from Groq (I love Groq for running most of the better open weight models), and other APIs from Mist...
Read more

Time and Attention Fragmentation in Our Digital Lives

  As humans we have evolved over a few million years to be both attentive and reactive to danger, live in social communities, and spend much of our time being in the present moment gathering and eating food and socializing. The behavior of rapidly changing short attention to content on social media, too many good short form things to watch on streaming video entertainment platforms, are all rewiring our brains in an unnatural and unhealthy way. I fight back, but in really simple ways that entail little ceremony: Almost every morning I spend 30 minutes scanning Hacker News (about 10 minutes), Apple News (about 5 minutes), and the remaining time on Twitter and Mastodon finding interesting new (mostly tech) things. I make notes in a temporary Apple Note: links of things I may want to research, try, or simply read that day. I like to get this all done at once, and then not feel like I need to interrupt my activities during the day to “catch up” on what is happening in the world. In a w...
Read more