UPDATE

This post has been updated to include the awesome instructions from Leo regarding using the postgis-unstable ppa. Thanks Leo!

1. Install PostGIS from PPA

System -> Administration -> Software Sources

Click on the “Other Software” tab.

Click on “+Add”

Enter: “ppa:ubuntugis/ubuntugis-unstable”

More info: https://launchpad.net/~ubuntugis/+archive/ubuntugis-unstable

Now install the package “postgresql-8.4-postgis”

2. Setup your database

createdb my_db
createlang plpgsql my_db
psql -d my_db -f /usr/share/postgresql/8.4/contrib/postgis-1.5/postgis.sql
psql -d my_db -f /usr/share/postgresql/8.4/contrib/postgis-1.5/spatial_ref_sys.sql
psql -d my_db -f /usr/share/postgresql/8.4/contrib/postgis_comments.sql

Now you should be able to make a geometry table.

3. Setup your geometry table

At this point I’m showing how to make an example table. Your usage of the PostGIS library will probably differ.

CREATE SEQUENCE points_id_seq;
CREATE TABLE points ( id INTEGER PRIMARY KEY DEFAULT NEXTVAL('points_id_seq') );
SELECT AddGeometryColumn('points', 'location', 4326, 'POINT', 2);
CREATE INDEX points_location_idx ON points USING GIST ( location );
 
// CREATE a point
INSERT INTO points(location) VALUES (ST_GeomFromText('POINT(-76.615657 39.327052)'));
 
// RETURNS the point
SELECT * FROM points WHERE ST_Distance(location, ST_GeomFromText('POINT(-76 39)')) < 1;
 
// Does NOT RETURN the point
SELECT * FROM points WHERE ST_Distance(location, ST_GeomFromText('POINT(-76 39)')) < .1;

But the answers are spread out and distributed randomly. Plus, I can only see “The program ‘______’ is currently not installed. You can install it by typing: sudo apt-get install ______” so many times before I lose interest and put off the task.

So, to prevent future headaches and help all of us out, I put together a how-to that can take a new Rails system from zero to code in a few minutes (depending on network speed) instead of half a day. With no further ado,

Setting up an Ubuntu box for Rails Development (including virtual machines)

Update everything

$ sudo aptitude update && sudo aptitude dist-upgrade

Install necessary packages

$ sudo aptitude install build-essential vim \
  vim-runtime git-core subversion libsqlite3-dev

We have projects in git (the newer ones) and svn, so we have to be able to switch fluidly between the two.

And I’m not trying to start a flame war, but Vim is the first choice for Rails development. You don’t have to take my word for it; Jamis Buck, Tim Pope, and Adam Lowe all say the same. I recommend the NERDTree, FuzzyFinderTextMate, BufExplorer, and rails.vim plugins if nothing else.

Install ruby

$ sudo aptitude install ruby1.8 ruby rdoc ruby1.8-dev \
  libpgsql-ruby1.8 libmysql-ruby1.8 irb libopenssl-ruby

Get rubygems from source. http://docs.rubygems.org/

$ wget http://rubyforge.org/frs/download.php/60718/rubygems-1.3.5.tgz

$ tar xzvf rubygems-1.3.5.tgz

$ cd rubygems-1.3.5

$ sudo ruby setup.rb

$ sudo ln -s /usr/bin/gem1.8 /usr/bin/gem

$ sudo gem update --system

Update ~/.gemrc (at least the :sources: chunk)

---
gem: --no-ri --no-rdoc
:benchmark: false
:verbose: true
:backtrace: false
:update_sources: true
:sources:
- http://gemcutter.org
- http://gems.rubyforge.org/
- http://gems.github.com

Install and setup Passenger (optional)

$ sudo apt-get install apache2-prefork-dev

$ sudo gem install passenger

$ sudo passenger-install-apache2-module

and follow the instructions passenger gives you. Most folks in the office run some form of an Apache-Passenger stack for development purposes. I can explain how that setup works in a future post.

Install geminstaller

$ sudo gem install geminstaller

Almost all of our legacy projects use geminstaller to manage gem dependencies. In the future, new projects will be moving to Bundler, but legacy projects matter and upgrading subsystems is not always justified.

“If it ain’t broke, don’t fix it” and the corollary: “because you probably won’t be able to bill it to the client” both apply.

Install common packages (optional, may be required by projects)

$ sudo aptitude install imagemagick

$ sudo gem install utility_belt open_gem redgreen

The first (imagemagick) is used by the Paperclip gem to manage files attached to Rails models. The second are tools that make Rails development more manageable on the command line. I highly recommend them. Besides, I’ve been sneaking redgreen in as a test dependency on our projects, so if you’re a developer here you’ll have to install it anyways.

Create an ssh key (follow instructions)

$ ssh-keygen

EXAMPLE PROJECT

All the stuff above won’t let you test-code-deploy without hassles, so here’s a sample run through of what the last mile of project-specific setup looks like.

Get the project. SVN, Git, whatever. Go to it.

$ svn co rails-project

$ cd rails-project

Run geminstaller

$ sudo geminstaller                                 # normal

$ sudo geminstaller -c config/test/geminstaller.yml # test env

Install necessary aptitude packages

$ sudo aptitude install texlive-latex-base

Don’t ask.

Create the test database

Mysql:

$ rake RAILS_ENV=test db:create

Postgres (using your username or DB username in place of “username”):

$ sudo -u postgres psql

postgres=# CREATE USER username SUPERUSER;

postgres=# CREATE DATABASE username OWNER username;

If you get an error regarding PGconn.quote_ident (Rails 2.3.x on Ubuntu 8.04) patch activerecord-2.3.4/lib/active_record/connection_adapters/postgresql_adapter.rb and add the following:

def PGconn.quote_ident(name)
  %("#{name}")
end

immediately after the “class PGresult” definition at the top of the file. Once that’s all done, the following:

$ rake RAILS_ENV=test db:create

$ rake RAILS_ENV=test db:schema:load

$ rake RAILS_ENV=test test

should work.

go have fun, write code, blow our minds

So that’s how we roll. Awkward requirements will still crop up as we pick up new projects (or very old projects) so you’ll always need a bit of apt/gem fu to get you through the day. Leave questions here or drop me a line at adam@smartlogicsolutions.com or http://twitter.com/abachman.

“Byobu is a Japanese term for decorative, multi-panel screens that serve as folding room dividers. As an open source project, Byobu is an elegant enhancement of the otherwise functional, plain, practical GNU Screen.”

https://wiki.ubuntu.com/MeetingLogs/openweekKarmic/Byobu

SSH into your server and install the two packages:

sudo apt-get install byobu landscape-common update-motd

Next, run byobu-config:

Change byobu settings with byobu-config

You can change Byobu’s colors if you’d like. I like the “dark” theme.

The important setting to change is the last one: “Byobu currently does not launch at login“. Select that and press return. Now you can go back to the menu and exit byobu-config (tab to the exit choice and hit return).

Now log out and log back in again. You’ll now access Byobu automatically.

Byobu as your session manager

The new MOTD (that’s “Message of the Day”, which is the text that is displayed when you login) has system information, thanks to landscape-common. This will let you know if your almost out of memory or disk space, or if you’re under heavy load.

Now let’s look at the information Byobu provides. The bottom row of Byobu contains, from left to right, your Distribution logo and name, uptime, load, cpu frequencies, ram amount and usage, and the date.

The upper row are your windows. Press F2 to create a new window. Along the bottom of the screen you’ll now see two entries in the top row of the footer. Press F3 to move to the previous window and F4 to move to the next window.

Press F8, then give the window a name, like “echo”. I like to name each tab with the task I’m doing, like “console”, “mysql”, and “top”.

You can press F7 to enter copy/scrollback mode. Use the arrow and page-up/down keys to move around your session. Press the spacebar to start copying. Now move your cursor somewhere else. Then press space again to copy the selection. Byobu doesn’t have a paste hotkey, so you have to use the screen hotkey, which is CTRL-a ] (thats CTRL-a, then let go of control and press ]).

You can press F12 to quickly lock your terminal, to grab a quick cup of coffee (or read this blog!).

Let’s explore how to maintain a session. Issue the following command:

echo hi

That will print out “hi” on the screen. Now let’s exit this session. Press the Byobu hotkey F6 to “Detach” from Byobu.

You’ll notice you’re still logged in, this is because Byobu is an application that runs on top of your session. So now you have to exit again to get back to your local machine.

Now SSH back into your machine. You’ll notice that command is still on the screen! “Detaching” does not end your session, it just detaches you from it. That means you can log in, run a long running task, and then Detach and come back in the morning when your task is done.

For extended information on Byobu, check out its Ubuntu Man Page.

2) Run:
> tune2fs -o journal_data_writeback /dev/sdXY
Where /dev/sdXY is replaced by the partition that you want to boost

4) Edit fstab

> nano -w /mnt/sdXY/etc/fstab

Find the line that references sdXY. It will look something like:

# /dev/sda2
UUID=be2f0ac2-4683-4550-bcd1-704a1a840b3e / ext4 relatime,errors=remount-ro 0 1

The first entry is the UUID (although on your system this could just be /dev/sdXY). The second entry is the path (/ for me). Third is the fstype (ext3/4). Fourth are the options. Fifth is for dump and sixth is pass. See man fstab(5) for more info.

Change the options to:

noatime,data=writeback,barrier=0,nobh,errors=remount-ro

(you can leave all of yours in place, if they weren’t the same as mine.

The main ones are replacing atime/relatime with noatime. This causes the FS to not write read-times to a file when read. Think about it. Writing to the FS for every read of the FS? crazy!

Next is data=writeback. This means that metadata for files can be written lazily after the file is written. This will not cause file system corruption, but it may cause the most recent changes to be lost in the event of a crash (so you may jump back into the past a bit).

Next is barrier, which is slightly more dangerous:

barrier=<0|1(*)> This enables/disables the use of write barriers in
the jbd code. barrier=0 disables, barrier=1 enables.
This also requires an IO stack which can support
barriers, and if jbd gets an error on a barrier
write, it will disable again with a warning.
Write barriers enforce proper on-disk ordering
of journal commits, making volatile disk write caches
safe to use, at some performance penalty. If
your disks are battery-backed in one way or another,
disabling barriers may safely improve performance.

Next is nobh:

bh (*) ext4 associates buffer heads to data pages to
nobh (a) cache disk block mapping information
(b) link pages into transaction to provide
ordering guarantees.
“bh” option forces use of buffer heads.
“nobh” option tries to avoid associating buffer
heads (supported only for “writeback” mode).

You can skip barrier and nobh if you’d like. noatime and data=writeback are the big ones.

6) Reboot to your system.

If you have any trouble booting, just boot a recovery disk and revert the fstab changes.

EDIT: Updated to no longer require recovery disk booting thanks to Nicolas Alpi’s response post.

Slow-Actions is great tool for determining the slow areas of a rails application. Since it is built on a rails log parser, it can be used for many other things. For example, here is some standard output from slow-actions when you want to know the speed of different user sessions within a specific date range:

slow-actions log/development.log --sessions --start-date=2009-03-01 --end-date=2009-04-01
           Cost    Average Max
+ ece0e17b48a5fe0fc766fa42f199fb66 (51 entries, 58% Error)
| Total:   2883.262 732.948 3100.00
| Render:  0.00000 0.00000 0.00000
| DB:      55.8220 14.1900 99.0000 

+ e1181ad94b34b41aff2a74ee62d5fb57 (10 entries, 30% Error)
| Total:   1563.912 676.276 1426.00
| Render:  0.00000 0.00000 0.00000
| DB:      14.5350 6.28500 19.0000 

+ 867bc340e6d65e673f29c57189feaf2b (133 entries, 0% Error)
| Total:   1083.138 221.450 386.000
| Render:  0.00000 0.00000 0.00000
| DB:      44.2030 9.03700 90.0000 

Etc...

Now, if we grep for “entries” we get a line for each session:

slow-actions log/development.log --sessions --start-date=2009-03-01 --end-date=2009-04-01 | grep entries
+ ece0e17b48a5fe0fc766fa42f199fb66 (51 entries, 58% Error)
+ e1181ad94b34b41aff2a74ee62d5fb57 (10 entries, 30% Error)
+ 867bc340e6d65e673f29c57189feaf2b (133 entries, 0% Error)
+ 99b39c7a9af55fc01056b5f127dc4c98 (75 entries, 0% Error)
+ 6ee15c4f3bc804ac68e9e868d9c3f7e6 (14 entries, 0% Error)
+ 80928c25c83590c4f89b91f8d4c8896d (9 entries, 0% Error)
+ c78cfa1cb086b3f473015b212ca3da11 (12 entries, 0% Error)
+ 48cd02cf6544493077c84eb16821bda2 (3 entries, 66% Error)
+ ac027817dcf87d473efb54cd737b2a80 (2 entries, 0% Error)
+ dff2ca2678852b06bbb6c7ca0a85b0a9 (1 entries, 0% Error)
+ 08ed3bc031c23bd3b2572ef7ce60d066 (1 entries, 0% Error)

Pipe that to word count, and we have the number of unique sessions within a specified time period:

slow-actions log/development.log --sessions --start-date=2009-03-01 --end-date=2009-04-01 | grep entries | wc -l
11

On a 54m log file, that takes only 0.761s!

I wanted to preview my HTML emails without having to fill up my online email inboxes with tons of email (and then I’d have to make filters too). I also didn’t want to manage actually sending real email. So, I set up my machine for local delivery. Read on for instructions.

I am running Ubuntu 9.04, however these instructions should be fine at least back to 8.04.

Step 1 – Install Postfix

sudo aptitude install postfix

During the install, choose “Local Delivery Only”

Step 2 – Configure Evolution for Receiving Locally

Open up Evolution “Applications->Internet->Evolution Mail”

Set up a new account and choose local delivery. When it asks you for a path, put in:

/var/mail/<username>

Note that this path may not exist if you’ve never received mail.

Step 3 – Configure Sanitize Email

In your rails test environment.rb put:

config.action_mailer.delivery_method = :sendmail

Then, in the initializer where you set up sanitize email:

ActionMailer::Base.sanitized_recipients = ["@"]
ActionMailer::Base.local_environments = %w( test )

If you need to know your username or hostname, just open up a terminal. The command “whoami” will give you your username, and “hostname” will give you the hostname.

Step 4 – Run your tests

Now, run your rails tests. You should have a test for every email you send, and that should trigger them to be sent locally. You may have to tell Evolution to Send/Receive. Keep in mind your tests will probably fail because they will expect email to be in test mode.

Step 5 – Set it back

Remember, when you’re done previewing your email, reset config.action_mailer.delivery_method!

Now then, the guide:

1) Download the 9.04 daily live from here:

http://cdimage.ubuntu.com/daily-live/current/

2) Burn or mount in a VM
3) Boot
4) Run the installer. When it asks for partitioning, select manual.
5) Create a small (128m is good) Ext2 primary partition and mount it at /boot
6) Create a swap primary partition (1024m is a good min, up to however much ram you have is good. No more than 4096m is necessary).
7) Create a third primary partition that uses the rest of the space, type Ext3, mount as root.
8) Proceed through the rest of the install.
9) When it asks you if you want to reboot, say “Continue using livecd”
10) Open a terminal
11) Your root partition should be /dev/sda3 if you just had those three partitions. If not, substitude /dev/sdaX for /dev/DEV when I mention it.
12) On the terminal, run “sudo tune2fs -O extents,uninit_bg,dir_index /dev/DEV”
13) Then run:

sudo fsck -pf /dev/DEV
sudo mkdir /mnt/root
sudo mount /dev/DEV /mnt/root
sudo nano -w /mnt/root/etc/fstab

and change the “ext3″ to “ext4″ on the / partition.
14) Reboot