Joe@Nitobi

January 9th, 2008

I noticed that I’ve been referring to DogOnRails a lot in my Ruby Examples (because I don’t like exposing our clients’ code to the outside world if I can avoid it), so I better talk about what it is other than it being an abstract example I use here!

What is Dog On Rails?

DogOnRails is a WifiDog Captive Portal Authentication Server. Unlike the WifiDog server, it is written in Ruby on Rails (hence the name). It originally started out as a small hobby project so I could use it to run on a Linksys WRT54G at my apartment and have it redirect to my Dreamhost account. Then some other people saw that I was working on the project on Google Code and started to help me out with it. Then I started doing this Meraki FreeTheNet stuff, which gave me a new platform to put WifiDog client, and this was the perfect opportunity to de-mystify the whole process.

So, why is it cool?

The original concept of WifiDog is what drew me to it. The original WifiDog project was designed so that Captive Portals, which were only being used by WISPs at the time could be used to display both user-centric and location-centric information to the user so that they would learn more about the area around them. The reason I started working with DogOnRails was because I am able to add more features faster with Rails than I would be able to with PHP, and the fact that I dislike the Smarty Templating Engine, which made adding larger features a major hassle.

There is also the fact that the project seemed to cater more and more to the WISP community than its original purpose, so I felt the server no longer was interesting.

The thing that I like about it is the fact that this allows anyone who can hack Ruby on Rails to add more features onto something that normally would require that you write in C or Shell Script. By moving the authentication off the device, you can do much more with the process than simple authentication, you could redirect the user to what you want to see before they are on their way. And since they’re using YOUR bandwidth anyway. The analogy here is showing a visitor to your house around before they sit down and watch television. It’s not always necessary, but it’s a good courtesy for those who haven’t been to your house before.

Oh yeah, did I mention that it was voted the Best of HackDay 1. I think that bars it from competing in Hack Day 2. I have a whole new killer app for that. :P

So, what features did you add during HackDay?

I added the following features:

• User-Agent detection for mobile devices
• GoogleMaps Functionality
• GoogleEarth Functionality

The User-Agent detection was much easier than I thought. I borrowed Alexei’s iPhone to test the final design, and at the end I was able to get the UserAgent detection to show the view easily, the code looks like this:

The rest is pretty self-explanitory at this point! After that was added, it was just a matter of doing some iPhone-based CSS. I used Facebook as an example of how to do this, and after cursing WebKit/Safari’s existance, I managed to get something that didn’t require a LOT of resizing to get working.

Of course, the following features were added post-hackday:

• ROBIN/Open-Mesh Update Recieving - (Can’t update settings yet, can get the Mesh status)
• Improved GoogleMaps Functionality - Looks more like the Merkai Map
• Per Node Auditing
• Graphs using gruff
• MAC Address Blocking
• Facebook Functionality

That’s right, DogOnRails is now a Facebook application as well. The idea behind this is to encourage people to grow Wifi networks like they would grow their own garden. Make it so that there’s a certain level of pride for having the nodes up and working. It’s very, very early alpha stages, but it exists and it currently looks like this:

It needs a lot more polish, but it’s going to be used by the FreeTheNet group in the coming month, and will be the replacement to the Meraki Dashboard that we have been looking it. There will probably be more changes to this, and to other things like this. But, when I refer to DogOnRails, I’m referring to a real app, and not some abstract thing like in a textbook.

And I will keep using it as an example of what to do and what NOT to do for many posts to come.

Posted in Linux, Rails, Ruby, mesh, FtN | 1 Comment »

October 14th, 2007

I was talking to someone about a new rails project, and we asked about which server would be the best one to work on. Of course, me being a person who loves apt-get and hates RPM, I said one word.

Debian

But then I had to point him to a place to go to make things easier. The problem is that deploying a Rails app is rarely easy, especially one that actually is meant to not die. Not only that, but I don’t always agree with all the tutorials. So I’m going to write a series of blog posts about how I’m going to do it. I’d recommend reading this post when it comes to installing ruby, rails and gems on Debian/Ubuntu but forget any of that Capistrano/Apache stuff that they talk about. I recommend vlad an nginx for setting up and deploying rails apps. We’re going to talk about nginx in thsi post.

So, the first thing that is done when setting up a production server is to choose the webserver. Now, conventional wisdom says that when you’re running Linux, you will most likely use Apache. Conventional Wisdom is very wrong, since Apache is a giant 800lb Gorilla of a webserver that has more features than you’ll ever possibly need. It’s great if you want to load things like mod_php or mod_python (which you would do with django, but that’s the topic for another post), but it sucks if you want to use it for Ruby, since we’re going to be forwarding everything to the mongrels anyway.

So, what do we use? We’re going to use the Big Red Webserver from Russia, nginx. nginx is a nice http/reverse proxy server, with small, human readable files. The first thing that we’re going to do is install it on Debian. Sudo as root and do this:

See, isn’t apt-get the coolest thing ever! Beats the crap out of yum! Anyway, what this just did was installed nginx, so in /etc/nginx, you are now going to have to delete your stock nginx file and create a new one. The first thing that you do is specify the user. It’s best to create a user for this such as www-data.

Note, we also set the log files. Now, we have to set some basic settings, such as the mime-type includes, the connections that we will accept, and gzipping your data. Simple, commonsense stuff. This begins the http configuration block:

OK, so far so good. Now, let’s specify some mongrel clusters. Depending on your app, you may want more or less clusters to balance the load. I’d ideally say at least 2 per processor, but sometimes you may want to run less of these for some weird reason. So, here’s what I have setup for a dual-processor machine.

We’re going to show how to setup this in mongrel later. This is what we have currently. Now, we have to specify the server.

Not much to see here. We’re using nginx as a proxy to the mongrel servers. We point to public just like how we would in any rails application that’s going to production, and we specify what we do in the case of a filename request. In the case that we request index, and index exists, we show the index.html page. Otherwise, we pass it all to mongrel. Then we use a closing brace to finish the scope.

Now, that was MUCH simpler than the beasts of Apache logs that you’d have to wade through to do the same thing. It’s interesting to note that nginx is a lightweight proxying server, and is actually designed to do this, as opposed to Apache which is more general purpose, and is meant to load web apps using shared libraries which is always much faster than doing something like using mongrel.

I’m not saying that nginx is the right tool for every job, in fact, I would use think seriously about using Apache for a Python/Django project, but that’s the topic of another post entirely. Stay tuned for my next post about Vlad the Deployer!

Posted in General, Linux, Rails, Ruby | 2 Comments »

October 5th, 2007

In the life of a web application, there comes a point where that shared hosting account just isn’t good enough (and you found out because your provider kicked you off), or your server just isn’t able to pull the queries from the database fast enough. Then one day, you finally get the filesystem error EMLINK, which you have a VERY hard time googling.

This is simple, you just created the maximum number of subdirectories that you can have in a directory. This is suprisingly not a common issue with file_column, acts_as_attachhment or attachment_fu, although I’m shocked as why it’s not. So, what do you do when you’re faced with scalability issues, and you’re image handling plugin is broken!

THROW IT ALL AWAY!

That’s what I had to do. Recently we worked on a site and we decided that because it was getting too hammered, that we would put the images on S3. Then we found the ultimate weakness of S3, which is that it’s not able to easily handle batch processing. We used the AWS:S3 library for most of the movement of the files, but we found that if we made a mistake, it would cost us hours to get these back.

Eventually, the day was saved with jetS3t, and Cockpit. Using jetS3t, we were finally able to actually get through all the S3 issues, and it saved the day at the end. (Actually, Dave saved the day at the end, my computer kept running out of memory). But we managed to get S3 support into it, and all we had to do was sacrifice File Column and replace it with this:

However, if you have to do S3, I would highly recommend using a long key so that you can sort your re.sults better based on this key! However, the biggest gotcha I found when adding S3 integration to my rails app was including AWS/S3. If you include and require it, it will break your routing, this is something that can cause hours of headaches, especially if you are doing something else. At the end, we learned that S3 is a misnomer. For a large number of files, it’s far from simple.

Posted in Uncategorized, Linux, Rails, Ruby | 1 Comment »