Administrative task in Rails

Rails
1

I have an administrative task that I need to run once a day: I need
to iterate through each user in the User table in the database, do
some calculation involving some other models, and update each user
record in the database.

I am thinking about just doing it at the console (env=production).
But I don’t want to type all the statements again each time I carry
out this task. Is there a way to put this in a script and just run
the script?

Eventually, I’d like to schedule the task to run automatically every
day, and have some sort of progress display when the task is run.

Thanks,

Vincent.

2

On Tue, Jan 26, 2010 at 8:47 PM, Vincent P [email protected] wrote:

Eventually, I’d like to schedule the task to run automatically every
day, and have some sort of progress display when the task is run.

Thanks,

Vincent.

Vincent, you might want to consider the whenver gem and you
can view Ryan’s screencast here:

http://media.railscasts.com/videos/164_cron_in_ruby.mov

Good luck,

-Conrad

3

You want to write a rake task that runs as a cron task every day.

lib/tasks/my_task.rake

task :touch_every_user => :environment do
User.find_each {|user| user.touch }

perform some other heavy calculation and save it back to the user

end

For the cron task:
go to server, type “crontab -e”
15 0* * * /path/to/rails/root rake touch_every_user
RAILS_ENV=production

4

On Tue, Jan 26, 2010 at 9:06 PM, Conrad T. [email protected]
wrote:

the script?
can view Ryan’s screencast here:

http://media.railscasts.com/videos/164_cron_in_ruby.mov

Good luck,

-Conrad

Vincent, you’ll install the gem as follows:

sudo gem install whenever

-Conrad

5

Thank you! This is exactly what I need.

6

On Tue, Jan 26, 2010 at 9:07 PM, David [email protected] wrote:

go to server, type “crontab -e”
15 0* * * /path/to/rails/root rake touch_every_user
RAILS_ENV=production

The Ruby way would be to do the following:

every :day , :at => “6:00 pm” do
runner “User.all.each { |user| <do_some_work> }”
end

Good luck,

-Conrad

7

Hi Vincent,

To answer your initial idea, … Yes, you can create a script, using
the same calls you would make in console, and run them using ./script/
runner. I do this all the time for various scripting tasks for
projects. One of the great features of rails.

You could do something like:

create the script to perform the updates:

$ cat ./script/update_users.runnable
puts “begin updating users: env=#{RAILS_ENV}”
begin
User.transaction do
User.find(:all).each do |u|
# perform calcs, update u, …
end
end
puts “done.”
rescue Exception=>e
#…
end

to run it against your dev env for testing:

$ ./script/runner ./script/update_users.runnable
begin updating users: env=development
…

to run it against your prod env:

$ ./script/runner -e production ./script/update_users.runnable
begin updating users: env=production
…

As for scheduling the task, you could use cron (or the windows equiv
if running under windows) to run the script at some particular
scheduled time/interval.

As for progress, you can always add logging calls in your script (and
likely a command-line arg as to whether or not to show debug info to
stdout, like the puts call in example above), either to the env’s
existing log, or depending on your needs/wants, to a separate log file
for the particular task at hand (ie ./log/
development_update_users.log ?), that you could check to see how the
process is going, how it went, errors encountered, etc.

Jeff

8

Learn by Doing wrote:

Thank you! This is exactly what I need.

(Please quote properly when replying.)

You will also want to use ar-extensions so that you’re not doing a
separate query for each User you update.

Best,
–Â
Marnen Laibow-Koser
http://www.marnen.org
[email protected]