As an offshoot on another thread someone asked for some feedback on development with Rails. They pointed out that there are plenty of pro-Rails resources on the net but were curious to hear some of the other side of experience with Rails.

This post is an edited version of the private reply I sent. To be honest I initially wasn’t going to put this up in public at all for risk of the wrath of the fan-boy legion, but I thought it was worth sharing a few of these thoughts.

First of all, let me say that Rails isn’t bad, and many Rails developers are fine developers. One of the smartest guys in the world I know loves Rails for all the right reasons and uses it very effectively.

I’d classify my caution about starting a project in Rails in three buckets-

Immature

Rails has progressed a bunch since I worked with it, but its still very immature compared to the other environments. Any Rails deployment that has more than a minor load (needs more than a shared hosting environment or on the order of a few thousand visits a day) will typically require a bunch of time dealing with infrastructure issues. When you install just about any modern copy of linux you are pretty well setup to run PHP or other more mature environments out of the box. Sophisticated people can tweak some stuff, but you get apache, mod_php and you are ready to go.

For Rails you don’t hit this much during development since everything is running on your machine with their nice little single threaded local server. But the minute you have any real load (lets call that 5 people are hitting your site at once) it can be a problem. I’m sure since my experience these things have improved a lot, but I still hear all the time from people about the pain of dealing with Mongrel and other deployment issues. What other major web app runtime doesn’t have an apache module? There are some of the core-Apache folks who I would listen to if they told me that Mongrel was really the right way to build this, but I haven’t heard from them yet.

Furthermore lots of the infrastructure is still coming along. There are some debuggers now, but they are still very new and given how much Rails does for you under the covers (more on this later) it can be really hard to figure out what went wrong. What it comes down to is do you really want to invest your resources into running Rails or into running your business? There are some very successful bigger sites that are built on Rails but they tend to have a dedicated staff of Rails experts, many of whom contribute to the Rails codebase. If you don’t have that guy, you need to hire that guy (not the one who thinks Rails is cool and picked up a book on it 6 months ago, but the one who really gets the details of the architecture and deployment) or you should be investing somewhere else.

Abstraction

For me, Rails typically does not operate at my favorite level of abstraction. All computer programming is about working in different levels of abstraction (unless you are at Intel working on the inners of the CPU and even there most of those folk work in abstractions, rather than individually manipulate individual logic gates). Picking the right level is the key. Rails really pushes you to a certain level of abstraction that makes rapid development easy, but often you don’t realize what is really going on under the covers since it handles it all for you. It is really easy to accidentally write a loop that does a database query through every iteration, but you don’t realize that is what is happening since it just looks like safe object references. Its easy to have too nested loops each doing more queries and just trash your performance.

All these things can be fixed by careful tuning and after all you have all the sources to this stuff. But Rails sets people up to work at that other layer and I’ve rarely met Rails developers who actually built a log of every SQL query that their app did to tune their performance. Again, this can be invisible if you only have a few users hitting your site every minute or for demos, but falls over quickly (and can be lots of work to fix) later.

This issue isn’t unique to Rails. .NET users can fall into the same traps if they just use all the existing libraries although the standard libraries from Microsoft tend to be a bit careful about making this stuff explicit. Any environment can have a framework that causes this problem although Rail’s ability to do late binding on objects can make it even harder to see what is happening. For example, I’ve done some work lately with Drupal, a framework written in PHP and it typically suffers from similar issues.

What’s The Big Deal

My personal reaction to the RoR hype is “what’s the big deal?” A talented developer with the right architectural expertise can do almost equivalent rapid development of web apps in PHP, .NET, Python, Java or Rails. They all have great tools and if you take the right approach they can all be pretty equivalent. The advantage of Rails is that it “puts you on rails”. Often, web-developers working with PHP, .NET or Java can build themselves a mess of either hacky spaghetti code or over-architected, unnecessarily complex stuff. I’ve seen both. Rails is very proscriptive about how you build an app so if your app fits into their model (typical data-driven web site stuff), most developers will be more likely to get it almost right.

Beyond that there are other stylistic things. Personally, I prefer C-style syntaxes over Smalltalk-style, so I’m more comfortable in C#, PHP, or Java. Other people really love the Ruby language.

There are some actual differences in the runtimes that you can poke at, putting some Pros and Cons in various columns but they are mostly a wash for general web-apps. There are some specialized apps that require certain perf characteristics that would steer me towards .NET or Java (where you get compiled performance and the ability to keep objects in local RAM in-between requests). Certain other apps have different characteristics that would steer me towards PHP, but for most it doesn’t really matter.

Again, Rails isn’t bad and the last thing in the world I would want to do is imply that I don’t approve of someone’s skills because they prefer Rails (or even that I would avoid a Rails project, despite it not being my first choice). I’m not a fan of some of the hype/fan-boy attitude surrounding Rails and I would advise folks that work in Rails to invest the time into understanding the details of what goes on in their environment, especially with respect to how it impacts database performance.

Two key tools for debugging things in Internet Explorer-

The IE Developer Toolbar

Fiddler HTTP web-proxy to let you see the real traffic. It even supports SSL.