Question

I’ve got a legacy Rails 2.3.2 application which has some functionality that allows a user to access some of the rake tasks via the browser. Just recently, the application stopped showing the list of available tasks (which it gets by running a shell command) in the browser.

On my development machine it works perfectly. It also works perfectly for a bunch of other production servers. However, any new production server I create this stops working.

Now here is the frustrating part. If I test the code in the console, it works perfectly even on the problematic production servers. I’ve even tested it by making calls via app.get in the console and it always works. I’ve tested this on both development and production environments in the console. Again, it only seems to fail in the browser.

Can anybody please suggest any strategies for figuring this thing out? Why would the response via the browser and via the console be any different?

Answer 1

It took a bit of digging but I figured this out so I thought I’d share what I found in case anybody else runs across a similar problem.

The answer lies in two aspects of the setup of our production server.

1. We use Phusion Passenger on our production servers (excellent system btw!) and as part of the config of Passenger it runs under a different user to the one I was accessing via the console. Normally, this is not an issue as the two users (the server user and the console user) have virtually the same permissions.

2. During the setup of the production server a mistake was made and one of the gems (in my case a fairly important one – i18n) was installed in the wrong location. Basically, when it was installed the sudo was missed at the start of the command. Thus, this one gem was installed in the console user’s home folder instead of the system gems folder.

Normally this particular situation is not an issue as all of the application runs normally. Its only when you try to run a shell command that requires access to that gem that it gives you grief.

Incidentally, this did not trigger an exception in the log even when I tried to access execute the rake tasks. It gave me the usual 500 internal server error but nothing was written to the log (which strikes me as kind of odd)

If you need to check something like this out, they way I eventually figured it out was to log in to the console as the server user and then try to run the shell command. As soon as I did it gave me an error saying it couldn’t find the required gem. I then checked the location of the gem using gem which command and saw that it had been installed in the wrong location.

I hope that someone finds this helpful and that it saves them time as I spent several days trying to figure this out.