Nov

20

Setup Ruby Enterprise Edition, nginx and Passenger (aka mod_rails) on Ubuntu

Filed Under Quick Tips, Ruby, Ruby on Rails | 6 Comments

The following is a very short guide on setting up Ruby Enterprise Edition (REE), nginx and Passenger, for serving Ruby on Rails applications on Ubuntu. It also includes a few quick and easy optimization tips.

We start with setting up REE (x64), using the .deb file provided by Phusion:

wget http://rubyforge.org/frs/download.php/66163/ruby-enterprise_1.8.7-2009.10_amd64.deb
sudo dpkg -i ruby-enterprise_1.8.7-2009.10_amd64.deb
ruby -v

In output you should see “ruby 1.8.7 (2009-06-12 patchlevel 174)…” or similar. If this is the case, good; while you are there, update RubyGems and the installed gems:

sudo gem update --system
sudo gem update

Next, you’ll need to install nginx, which is a really fast web server. The Phusion team has made it very easy to install, but if you simply follow most instructions found elsewhere, you’ll get the following error:

checking for system md library ... not found
checking for system md5 library ... not found
checking for OpenSSL md5 crypto library ... not found

./configure: error: the HTTP cache module requires md5 functions
from OpenSSL library.  You can either disable the module by using
--without-http-cache option, or install the OpenSSL library in the
system,
or build the OpenSSL library statically from the source with nginx by
using
--with-http_ssl_module --with-openssl=
 options.

Instead, we are going to install libssl-dev first and then nginx and its Passenger module:

sudo aptitude install libssl-dev
sudo passenger-install-nginx-module

Follow the prompt and accept all the defaults (when prompted to chose between 1 and 2, pick 1).

Before I proceed with the configuration, I like to create an init script and have it boot at startup (the script itself is adapted from one provided by the excellent articles at slicehost.com):

sudo vim /etc/init.d/nginx

The content of which needs to be:

#! /bin/sh

### BEGIN INIT INFO
# Provides:          nginx
# Required-Start:    $all
# Required-Stop:     $all
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: starts the nginx web server
# Description:       starts nginx using start-stop-daemon
### END INIT INFO

PATH=/opt/nginx/sbin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DAEMON=/opt/nginx/sbin/nginx
NAME=nginx
DESC=nginx

test -x $DAEMON || exit 0

# Include nginx defaults if available
if [ -f /etc/default/nginx ] ; then
    . /etc/default/nginx
fi

set -e

. /lib/lsb/init-functions

case "$1" in
  start)
    echo -n "Starting $DESC: "
    start-stop-daemon --start --quiet --pidfile /opt/nginx/logs/$NAME.pid \
        --exec $DAEMON -- $DAEMON_OPTS || true
    echo "$NAME."
    ;;
  stop)
    echo -n "Stopping $DESC: "
    start-stop-daemon --stop --quiet --pidfile /opt/nginx/logs/$NAME.pid \
        --exec $DAEMON || true
    echo "$NAME."
    ;;
  restart|force-reload)
    echo -n "Restarting $DESC: "
    start-stop-daemon --stop --quiet --pidfile \
        /opt/nginx/logs/$NAME.pid --exec $DAEMON || true
    sleep 1
    start-stop-daemon --start --quiet --pidfile \
        /opt/nginx/logs/$NAME.pid --exec $DAEMON -- $DAEMON_OPTS || true
    echo "$NAME."
    ;;
  reload)
      echo -n "Reloading $DESC configuration: "
      start-stop-daemon --stop --signal HUP --quiet --pidfile /opt/nginx/logs/$NAME.pid \
          --exec $DAEMON || true
      echo "$NAME."
      ;;
  status)
      status_of_proc -p /opt/nginx/logs/$NAME.pid "$DAEMON" nginx && exit 0 || exit $?
      ;;
  *)
    N=/etc/init.d/$NAME
    echo "Usage: $N {start|stop|restart|reload|force-reload|status}" >&2
    exit 1
    ;;
esac

exit 0

Change its permission and have it startup at boot:

sudo chmod +x /etc/init.d/nginx
sudo /usr/sbin/update-rc.d -f nginx defaults

From now on, you’ll be able to start, stop and restart nginx with it. Start the server as follows:

sudo /etc/init.d/nginx start

Heading over to your server IP with your browser, you should see “Welcome to nginx!”. If you do, great, we can move on with the configuration of nginx for your Rails app.

Edit nginx’ configuration file:

sudo vim /opt/nginx/conf/nginx.conf

Adding a server section within the http section, as follows:

    server {
        listen 80;
        server_name example.com;
        root /somewhere/my_rails_app/public;
        passenger_enabled on;
        rails_spawn_method smart;
    }

The server name can also be a subdomain if you wish (e.g., blog.example.com). It’s important that you point the root to your Rails’ app public directory.

The rails_spawn_method directive is very efficient, allowing Passenger to consume less memory per process and speed up the spawning process, whenever your Rails application is not affected by its limitations (for a discussion about this you can read the proper section in the official guide).

If you have lots of RAM (e.g., more than 512 MB) on your server, you may want to consider increasing you maximum pool size, with the directive passenger_max_pool_size from its default size of 6. Conversely, if you want to limit the number of processes running at any time and consume less memory on a small VPS (e.g., 128 to 256MB), you can decrease that number down to 2 (or something in that range). (Always test a bunch of configurations to find one that works for you). You can read more about this directive, in the official guide.

While you are modifying nginx’ configuration, you may also want to increase the worker processes (e.g., to 4, on a typical VPS) and add a few more tweaks (such as enabling gzip compression):

# ...
http {
    passenger_root /usr/local/lib/ruby/gems/1.8/gems/passenger-2.2.5;
    passenger_ruby /usr/local/bin/ruby;

    include       mime.types;
    default_type  application/octet-stream;

    access_log  logs/access.log;

    sendfile        on;
    keepalive_timeout  65;
    tcp_nodelay on;

    gzip on;
    gzip_comp_level 2;
    gzip_proxied any;   

    server {
    #...

When you are happy with the changes, save the file, and restart nginx:

sudo /etc/init.d/nginx restart

If you wish to restart Passenger in the future, without having to restart the whole web server, you can simply run the following command:

touch /somewhere/my_rails_app/tmp/restart.txt

Passenger also provides a few handy monitoring tools. Check them out:

sudo passenger-status
sudo passenger-memory-stats

That’s it, you are ready to go! I hope that you find these few notes useful.

Oct

19

Add code highlighting to your Google Waves

Filed Under General, Quick Tips | 5 Comments

Google Wave is still rough around the edges, but it has a lot of potential in terms of becoming a great collaboration tool. As a developer, your first question will probably be: “How do I add code highlighting to my waves?”. The answer is straightforward, however not very easy to find if you google it. I hope this post will help fellow developers who are experimenting with Google Wave.

The following steps are required to obtain syntax highlighting for your code:

  1. Create a new wave and add the Syntaxy robot to your wave. Use the wave address: kasyntaxy@appspot.com.
  2. Reply to your first message or within it, thereby creating a reply (called “blip” in Google lingo).
  3. Specify your code’s language, prefixing the name with a hash and exclamation mark, like #!python or #!ruby.

At this point, as you type the code in your blip it will be highlighted by the Syntaxy bot as shown in the picture below:

Highlight code on Google Wave

More advanced automatic syntax highlighting bots will probably appear as Google Wave progresses, but this one should do the trick for now. On a side note, if you copy and paste code from XCode, the code formatting will be kept in your waves and blips without the need for bots.

Oct

8

Getting MacRuby’s compiler to work

Filed Under Mac, Quick Tips, Ruby | 5 Comments

MacRuby's logoThere is major news in Rubyland today. MacRuby’s team just released their fist beta of version 0.5 (an experimental, still incomplete version of Ruby), which brings JIT, removal of the dreaded GIL (Global Interpreter Lock), native threads, GCD (Grand Central Dispatch) for multicore computing, and a whole new set of features found in the release announcement to the table.

The most important new feature is the presence of a compiler. That’s right, thanks to this release, Ruby code can now become highly optimized executable code. How awesome is that? I can sense that you’re pumped by this news, so why not head over to MacRuby.com and download the installation file for yourself? After you’ve done that, the next thing you’re going to want to do is run a small test like the following:

$ macrubyc world_domination.rb -o world_domination
Can't locate program `llc'

Oh noes! llc is a tool that ships with the LLVM (upon which MacRuby is built), however it’s not included with MacRuby’s installer (it will be in the future). But fear not my friends, there is a solution:

$ svn co -r 82747 https://llvm.org/svn/llvm-project/llvm/trunk llvm-trunk
$ cd llvm-trunk
$ ./configure
$ UNIVERSAL=1 UNIVERSAL_ARCH="i386 x86_64" ENABLE_OPTIMIZED=1 make -j2
$ sudo env UNIVERSAL=1 UNIVERSAL_ARCH="i386 x86_64" ENABLE_OPTIMIZED=1 make install

If your machine does not have 2 cores, remove the -j2 option from the fourth line or adjust the number accordingly.

The compilation phase may take a couple of centuries, depending on your machine’s speed, but it should eventually build the LLVM. :-P llc will be placed in your PATH, and you’ll finally be able to compile Ruby code and obtain an executable to help you carry out your world domination plans.

$ macrubyc world_domination.rb -o world_domination
$ ./world_domination
MUAHAHAHAHA!

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