How to use multi-threading in rails 3?

Question

I am sending mail to the users using actionmailer through postmark. This is my code in controller:

@users = User.where(some condition)
@product = Product.find_by_name(some name).first
for user in @users
  UserMailer.new_product_arrival(user, @product, home_url).deliver
end

and this my user_mailer.rb

def new_product_arrival(user,product,home_url)
  @from         = Settings.mailer_from_address
  @recipients   = user.login
  @sent_on      = Time.now
  @user = user
  @product = product
  @content_type = "text/html"
  @home_url = home_url
end

The problem is that if there are more than 10 users it takes a very long time because of the for loop. I need to know if we can handle this by using multi-threading or background job. I don't want to use background job, but can anyone tell me how to implement the above using multi-threading.

I am using ruby 1.8.7 and rails 3.0.7

Audacity

I'm not at all a ruby expert (yet) but postmark does support sending batch emails, so if you're emailing a large group of users, it might be easier for you to use that rather than an api call for each one. – Capello

Answer 1

There basically two ways to wrap your loop in order to get "multi-threading":

1. Spwan a thread for each delivery and join them back to the main thread

   threads = []
   for user in @users
      threads << Thread.new do
        UserMailer.new_product_arrival(user, @product, home_url).deliver
      end
   end
   threads.each(&:join)
   

2. fork over the entire rails app ( pretty messy but the rails app serving the request will respond immediately ) and have the process detached:

   process = fork do
     for user in @users
       UserMailer.new_product_arrival(user, @product, home_url).deliver
     end
     Process.kill("HUP") 
     #sends the kill signal to current Process, which is the Rails App sending your emails 
   end
   Process.detach(process)
   

Hope that helps

Arteriole

Will try this in my application. – Audacity

When using threads you might want to add at the end of the Thread block: ActiveRecord::Base.connection.close (if the threads have DB calls, which they should have in your example). – Altorelievo

Answer 2

our developer Artem recently made a major update to the Postmark gem

which allows you to send emails easily in batches, which should allow you to send emails faster. Check it out.

Sabbatarian

Answer 3

Try delayed_job gem. This is a database-based background job gem. We used it in an e-commerce website, for example, sending order confirmation emails to users.

These tasks can happen asynchronously in the background, because your Rails app doesn't need them executed immediately.

Maestas

"I don't want to use background job" -OP – Stickle

Answer 4

um im a rails student from nairobi dev school kenya ..and i think you can give this a try ,..soo what you are having there is the delayed response due to the number of users ..you can try long polling an example

poll = function (){
  s.ajax{
       url:/'chat.json'
       data: { last_time: get last_time () }
     }}.done(function(data) {
     // handle data
     setTimeout(poll,1000);
     });
}

try that in your ow way ..this is useful for a real time application..o you can use even action controller:: live ..i think youre farmiliar with threading with rails .also .the above exmples will hep you ,,hopefuly \

Toole