Developing a Rails app in Netbeans/JRuby but deploying to Ruby (C)

Question

I'm using Netbeans and JRuby to develop a Rails web application.

But for deployment, I will be using Heroku.

Since Heroku uses the Ruby-C implementation, I was wondering my use of JRuby can cause problems? Is this approach a safe thing to do?

Answer 1

Hi Zabba,

funny thing: I stumbled in your question while looking for a tool chain to do it the other way round (developing in MRI Ruby, deploying with JRuby). Of course you can not use any Java classes and internals, but this for sure is obvious to you. According to my results thus far you shouldn't encounter any process structural issues, because MRI Ruby adheres to the shared nothing principle whereas your requests in the development app share the VM at least. Maybe to be shure you should hae a look at http://kenai.com/projects/jruby/pages/DifferencesBetweenMriAndJruby and read it in a reverse sense, especially the "Native Endian is Big Endian" paragraph when un-/packing Strings or Arrays.

Answer 2

You can develop in NetBeans and use C-Ruby (aka MRI Ruby). Just install Ruby separately, go to Ruby Platforms, and select it. I highly recommend you install a separate Ruby anyway, whether or not it is MRI Ruby, because if you use the built-in NetBeans version of JRuby (which is often not the latest) and then upgrade NetBeans, you'll lose all the gems you've installed. Installing Ruby/JRuby outside of NetBeans helps you to better manage the versions and gems.

Now to answer your questions: Likely you will not encounter problems with basic Rails applications. If you ever have the need to use non-native libraries you may run into issues. Some gems (e.g. Nokogiri) have a C version and a Java version so you'd be OK, but if you wanted to use a plugin that relied on RMagick, for example, you'd struggle, as you'd probably go a different route if you were developing and deploying with JRuby.

Bottom line: I wouldn't recommend it. I'd recommend using the same platform for both. But you can use MRI Ruby in NetBeans.

Answer 3

You will save yourself a lot of trouble if you develop on the same platform as you deploy. This goes for OS as well, especially Windows then deploying on Linux, less so with OSX, but still sometimes an issue. You will be troubleshooting on your deployment system and that just isn't the same as catching something as you code it in development. I recently started using JRuby for a project and there are quite a few differences and different gems altogether in some cases.

As for loosing installed gems etc. take a look at using Bundle while you are at it, that will also save you some trouble down the line with gem versions out of sync.