CODEWITHSUNDEEP
ruby-on-railsruby
Cannon Moyer
Cannon Moyer

Reputation: 3164

Kill Background Thread - Ruby on Rails

I've created a module that starts a Thread which sends out emails ever 5 minutes. I start the thread by running a rake task once which loads in a module which starts the thread like this: 

require "#{Rails.root}/app/lib/Cron.rb"

namespace :cron_starter do
   desc "TODO"
   task start: :environment do
      Cron.run
   end

end

The code Cron.run calls my module method that starts the thread which runs an infinite loop. All of this works fine, but what do I do if I need to kill the thread? Is there a way to attach to the thread via another rake task and kill it? I could always write to a basic txt file and kill it that way based on flag, but that doesn't seem very elegant. Thanks in advance.

UPDATE

I tried 

ps aux | grep cron_starter:start

the output I got was 

root     11358  0.0  0.0  12944  1088 pts/0    S+   14:30   0:00 grep --color=auto cron_starter:start

I'm not real sure if any of the numbers are process ids, so I attempted to run

kill -9 11358

kill -9 12944

The CLI responded with No such process

UPDATE 2

I've tried printing Thread.current.object_id to a log file and I've attempted to kill the thread from this ID as well but again I get the same error as above.

Upvotes: 0

Views: 718

Answers (3)

Cannon Moyer
Cannon Moyer

Reputation: 3164

So I figured it out finally. The problem was that I was launching a new Thread and not a new Process

I fixed the issue by creating a new process like this:

Process.fork do
   #my code here that loops forever
   logProcess(Process.pid) #this function is an external function that I created that writes the parameter to a file. 
   #you can use the id from Process.id to kill the process from the CLI.

end

You can kill the process by getting the value of Process.id and running 

kill -9 process_id_goes_here

Upvotes: 0

kojha31
kojha31

Reputation: 11

You can do:

ps aux | grep #rake_task_name
kill -9 pid

Upvotes: 1

sakurashinken
sakurashinken

Reputation: 4080

I would install and use sidekiq for this. It comes with a dashboard and you can configure cron via the gem sidekiq-scheduler. You can then quiet or kill the job queue from the dashboard, which will stop the emails. Honestly, if you have cron jobs on ROR you should have an active job extension like sidekiq anyways.

Baring that, I would indeed write the pid to a text file and kill via the pid.

Upvotes: 0

Related Questions