whenever + delayed_job with cron job in starting worker

问题

I am learning cron job and delayed job, and I want to send emails using background job; for that I'm using the delayed_job gem. I don't want to start the worker manually by running the rake jobs:work command, but I want to set this rake in cron job so whenever an user login into the dashboard this command is fired and a mail is sent to his address. Following is my code:

Sending mail method

def dashboard      
    @user = User.find(params[:id])      
    UserMailer.delay.initial_email(@user)      
end      

UserMailer

def initial_email(user)      
    @user = user     
    mail(:to => user.email,:subject => "Welcome to my website!")       
end      

For the cron job I am using "whenever" Gem, so what should I write in my schedule.rb file so that when I login into the dashboard I get a mail without running worker manually?

回答1:

DelayedJob is supposed to be running all the time in the background so it doesn't need to be fired up. The worker agent checks the queue to see if any tasks need to be performed, and runs them. It's pretty much like a 2nd instance of your application that runs in the background checking for tasks that need to run.

So you should start the worker agent with script/delayed_job start and let it run all the time. You can use a separate tool like monit or god to monitoring your worker agent to make sure it is always running.

来源：https://stackoverflow.com/questions/10256331/whenever-delayed-job-with-cron-job-in-starting-worker