Cron Job Rails 3 - Loading system ruby not RVM ruby - ruby-on-rails-3

Question

I'm trying to set up a cron job with the following command:
crontab -l
Begin Whenever generated tasks for: myapp
* * * * * /bin/bash -l -c 'cd /Users/boris/projects/myapp && script/rails runner "Resque.enqueue(MyModel)"'
I get the following error; in which I see its loading Ruby 1.8. The problem is I'm using RVM with ruby 1.9.2. How do I specify the correct RVM path in CRON?
Subject: Cron <boris#jz> /bin/bash -l -c cd /Users/boris/projects/myapp && script/rails runner "Resque.enqueue(Place)"
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=boris>
X-Cron-Env: <USER=boris>
X-Cron-Env: <HOME=/Users/boris>
Message-Id: <20110523022400.A5B242C608D#jz.local>
Date: Sun, 22 May 2011 19:24:00 -0700 (PDT)
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- bundler/setup (LoadError)
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
from /Users/boris/projects/myapp/config/boot.rb:6
from script/rails:5:in `require'
from script/rails:5
How do I specify the correct RVM path in CRON?
Thanks in advance
Ruby path with which ruby:
/Users/boris/.rvm/rubies/ruby-1.9.2-p180/bin/ruby

Answer 1

Please do not use the -l switch in cron jobs. The --login switch instructs bash to run as a login shell. Therefore, it will load your environment, and things might appear to work. However, cron jobs are by nature non-interactive, non-login shells. Invoking them as if they were is just bad practice. Also, when bash starts a login shell, it first loads the system environment (/etc/profile), and if in that file something needs to print to the screen (like motd), your cron job will report nasty errors like this:
stty: TIOCGETD: Inappropriate ioctl for device
You don't need to write a cron runner neither (following that logic, you might as well write a cron runner runner). Please keep things simple. All you need to do is configure your cron job to launch a bash shell, and make that bash shell load your environment.
The shebang line in your script should not refer directly to a ruby executable, but to rvm's ruby:
#!/usr/bin/env ruby
This instructs the script to load the environment and run ruby as we would on the command line with rvm loaded.
On many UNIX derived systems, crontabs can have a configuration section before the actual lines that define the jobs to be run. If this is the case, you would then specify:
SHELL=/path/to/bash
This will ensure that the cron job will be spawned from bash. Still, your environment is missing, so to instruct bash to load your environment, you will want to add to the configuration section the following:
BASH_ENV=/path/to/environment (typically .bash_profile or .bashrc)
HOME is automatically derived from the /etc/passwd line of the crontab owner, but you can override it.
HOME=/path/to/home
After this, a cron job might look like this:
15 14 1 * * $HOME/rvm_script.rb
What if your crontab doesn't support the configuration section. Well, you will have to give all the environment directives in one line, with the job itself. For example,
15 14 1 * * export BASH_ENV=/path/to/environment && /full/path/to/bash -c '/full/path/to/rvm_script.rb'
Full blog post on the subject

Answer 2

Your problem is that you're executing two commands but not as you expect. The two commands are:
/bin/bash -l -c cd /Users/boris/projects/myapp
script/rails runner "Resque.enqueue(MyModel)"
With the second only executing if the first succeeded. I think you just need some quotes:
* * * * * /bin/bash -l -c 'cd /Users/boris/projects/myapp && script/rails runner "Resque.enqueue(MyModel)"'
Those single quotes will feed your cd ... && script/rails ... pair to /bin/bash as a single command and that should change the current working directory to what you want when script/rails is executed.

Answer 3

Easiest solution is to use this command instead:
Begin Whenever generated tasks for: myapp
* * * * * /bin/bash -l -c 'cd /Users/boris/projects/myapp && ./script/rails runner "Resque.enqueue(MyModel)"'