I have a ruby script that connects to an Amazon S3 bucket and downloads the latest production backup. I have tested the script (which is very simple) and it works fine.
However, when I schedule this script to be run as a cron job it seems to fail when it loads the Amazon (aws-s3) gem.
The first few lines of my script looks like this:
#!/usr/bin/env ruby
require 'aws/s3'
As I said, when I run this script manually, it works fine. When I run it via a scheduled cron job, it fails when it tries to load the gem:
`require’: no such file to load — aws/s3 (LoadError)
The crontab for this script looks like this:
0 3 * * * ~/Downloader/download.rb > ~/Downloader/output.log 2>&1
I originally thought it might be because cron is running as a different user, but when I do a ‘whoami’ at the start of my ruby script it tells me it’s running as the same user I always use.
I have also done a bundle init and added the gem to my gemfile, but this doesn’t seem to have any affect.
Why does cron fail to load the gem? I am running Ubuntu.
If you’re running it manually and it works you’re probably in a different shell environment than cron is executing in. Since you mention you’re on Ubuntu, the cron jobs probably execute under /bin/sh, and you’re manually running them under /bin/bash if you haven’t changed anything.
You can debug your environment problems or you can change the shell that your job runs under.
To debug, There are several ways to figure out what shell your cron jobs are using. It can be defined in
or you can make a cron job to dump your shell and environment information, as has been mentioned in this SO answer: How to simulate the environment cron executes a script with?
To switch to that shell and see the actual errors causing your job to fail, do
Then running your script you should see what the errors are and be able to fix them (rubygems?).
Option 2 is to switch shells. You can always try something like:
To force your job into bash. That might also clear things up.