pastbedti.me » Programming

Change PATH environment with Rails and Capistrano

Mathias Stjernström — Wed, 01 Jun 2011 20:09:49 +0000

Note to self.

When deploying my RubyOnRails applications with Capistrano and I get errors like this one

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servers: ["app.myserver.com"]
[app.myserver.com] executing command
** [out :: app.myserver.com] sh: bundle: command not found
command finished in 31ms
servers: ["app.myserver.com"] [app.myserver.com] executing command ** [out :: app.myserver.com] sh: bundle: command not found command finished in 31ms

Capistrano executes the commands in a very basic shell so the $PATH environment are not the same as when you login through SSH.

One way to solve this is by setting PermitUserEnvironment to yes in /etc/sshd_config and then add the correct PATH to ~/.ssh/environment

I just found another way that was much easier

In you config/deploy.rb add the following snippet

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set :default_environment, {
'PATH' => "/opt/ruby-enterprise/bin/:$PATH"
}

Thats it!

Cheers!

Nokogiri quote

Mathias Stjernström — Fri, 02 Apr 2010 20:12:14 +0000

I just have to share this funny quote from the nokogiri website (for those of you that does not know 鋸 it’s a reeeeeeeeaaally good and fast HTML, XML, SAX, and Reader parser).

XML is like violence – if it doesn’t solve your problems, you are not using enough of it. – http://nokogiri.org/

Cheers!

Deploying a Sinatra app with Apache and Phusion Passenger a.k.a. mod_rack

Mathias Stjernström — Mon, 30 Nov 2009 22:01:30 +0000

My Sinatra + Apache + Passenger setup did not just run

Deploying a simple Sinatra rack application under Apache and Phusion Passenger turned out not work out of the box for me.

I already had a virtual host so I decided to deploy with passengers sub URI (sub URI documentation).

To make this work you’ll need Apache installed with Phusion Passenger setup (Passenger installation)

This is what I started with

This is my folders for the already existing website.

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# Existing homedir
/home/my_web/
# Current webroot
/home/my_web/htdocs

Creating folders and files for Sinatra

The first thing you want to do is to create folders and files for Sinatra.

1	mkdir /home/my_web/sinatra

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cd /home/my_web/sinatra
mkdir tmp
mkdir logs
mkdir public
touch app.rb
touch config.ru

Create symlink

Create a symbolic link from our current webroot to the new Sinatra app so that apache/passenger can find it.

1	ln -s /home/my_web/sinatra/public /home/my_web/htdocs/app

Creating the application

We also need a Sinatra application for this to work so lets fill those files.

File: config.ru

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require 'app'

set :environment, ENV['RACK_ENV'].to_sym
set :app_file, 'app.rb'
disable :run

log = File.new("logs/sinatra.log", "a")
STDOUT.reopen(log)
STDERR.reopen(log)

run Sinatra::Application

File: app.rb

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require 'rubygems'
require 'sinatra'

before do
# Strip the last / from the path
request.env['PATH_INFO'].gsub!(/\/$/, '')
end

get '' do
"Hello world"
end

Apache configuration

Now we need to setup apache so that it can find our Sinatra app and load it.

The only thing you need to do is add the following line to your existing VirtualHost block:

1	RackBaseURI /app

This line will tell passenger to look into our existing webroot for a symlink thats named app and which points to our rack app. (RackBaseURI documentation)

Virtual host entry

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<VirtualHost *:80>
ServerName www.example.com
ServerAlias example.com
DocumentRoot /home/my_web/htdocs/
RackBaseURI /app

<Directory "/home/my_web/htdocs/">
Order allow,deny
Allow from all
AllowOverride All
Directory>
VirtualHost>

The best part is that you are allowed to specify this option multiple times. So you can easily setup multiple apps under the same virtual host.

Cheers!

Grouping a timestamp field by date in Ruby On Rails / PostgreSQL

Mathias Stjernström — Sun, 08 Nov 2009 00:55:09 +0000

Recently I’ve been working a lot with dates and tonight I had a hard time finding information about how to group a model by date when the model only have a timestamp column.

Lets pretend we have a user model with a created_at attribute which is stored as a timestamp.

If we want to plot a simple graph showing signups per date this is the way to extract them:

1	User.count(:group => "DATE(created_at)")

Thats all there is to it. From this you will get an OrderedHash containing the date and count of users for each date.

One small thing to remember if you are using PostgreSQL. You will need the DATE() function in any ORDER/SELECT statements because PostgreSQL will only select/order by fields thats in the GROUP BY statement and this is a pretty healthy behavior that many databases (no names here) don’t care about. Think about it. If you are grouping all users by date and use * as selector how would the database know which username or email address to display?

This is what happens if you try to group by created_at without DATE() ->

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>> User.count(:order => 'created_at DESC', :group => ["DATE(created_at)"])
ActiveRecord::StatementInvalid: PGError: ERROR: column "users.created_at" must appear in the GROUP BY clause or be used in an aggregate function
: SELECT count(*) AS count_all, DATE(created_at) AS date_created_at FROM "users" GROUP BY DATE(created_at) ORDER BY created_at DESC
from /tmp/app/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log'
from /tmp/app/vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:507:in `execute'
from /tmp/app/vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:985:in `select_raw'
from /tmp/app/vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb:972:in `select'
from /tmp/app/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache'
from /tmp/app/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:62:in `select_all'
from /tmp/app/vendor/rails/activerecord/lib/active_record/calculations.rb:255:in `execute_grouped_calculation'
from /tmp/app/vendor/rails/activerecord/lib/active_record/calculations.rb:132:in `calculate'
from /tmp/app/vendor/rails/activerecord/lib/active_record/calculations.rb:130:in `catch'
from /tmp/app/vendor/rails/activerecord/lib/active_record/calculations.rb:130:in `calculate'
from /tmp/app/vendor/rails/activerecord/lib/active_record/calculations.rb:48:in `count'
from (irb):18

And this is the right way to do it:

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>> User.count(:order => 'DATE(created_at) DESC', :group => ["DATE(created_at)"])
=> #22, "2009-10-25"=>4, "2009-11-04"=>8, "2009-10-15"=>9, "2009-10-26"=>16, "2009-11-05"=>9, "2009-10-16"=>193, "2009-10-27"=>14, "2009-11-06"=>9, "2009-10-17"=>49, "2009-10-28"=>15, "2009-11-07"=>6, "2009-10-18"=>36, "2009-10-29"=>8, "2009-10-19"=>116, "2009-10-30"=>15>

As you may notice the Hash does not look ordered. But if you loop over it you will get them in order:

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>> User.count(:order => 'DATE(created_at) DESC', :group => ["DATE(created_at)"]).each {|u| puts "#{u[0]} -> #{u[1]}" }
2009-11-07 -> 6
2009-11-06 -> 9
2009-11-05 -> 9
2009-11-04 -> 8
2009-11-03 -> 14
2009-11-02 -> 20
2009-11-01 -> 10
2009-10-31 -> 6
2009-10-30 -> 15
2009-10-29 -> 8
..

And thats how you group a timestamp field with just its date part.

Cheers!

Painful experience with rails InvalidAuthenticityToken

Mathias Stjernström — Mon, 23 Mar 2009 19:22:25 +0000

Today I had a really painful experience with rails InvalidAuthenticityToken. It turned out not to have anything to do with rails at all and there is where the painful part come in to play.

We had an application which needed a staging environment. When everything where setup and after the first deploy to the new environment everything seemed fine at first but when we tried to login we got these fine messages:

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ActionController::InvalidAuthenticityToken (ActionController::InvalidAuthenticityToken):
/vendor/rails/actionpack/lib/action_controller/request_forgery_protection.rb:86:in `verify_authenticity_token'
/vendor/rails/activesupport/lib/active_support/callbacks.rb:178:in `send'
/vendor/rails/activesupport/lib/active_support/callbacks.rb:178:in `evaluate_method'
/vendor/rails/activesupport/lib/active_support/callbacks.rb:166:in `call'
/vendor/rails/actionpack/lib/action_controller/filters.rb:225:in `call'
/vendor/rails/actionpack/lib/action_controller/filters.rb:629:in `run_before_filters'
/vendor/rails/actionpack/lib/action_controller/filters.rb:615:in `call_filters'
/vendor/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
/vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'

After about two hours of troubleshooting the only problem left where that the browser did not get the cookie. We used telnet to check the headers and the cookie where there… ok, the browser is broken…. sure…

Then, finally it came to me… what if,… the hostname is broken? Broken hostname you tell me? Just for fun I changed the hostname and bada-bong bada-bing everything is working…. Now I get this creepy feeling of the big mistake I have made…

The thing is that I have worked with domains for many years and I know very well that you CANNOT have underscores in your domains. But my peanut brain do not think of subdomains as a domain-name. So we had a sub-domain with an underscore. Putting a underscore in the domainname makes Safari and some versions of Explorer not to accept cookies and that makes rails AuthenticityToken to treat me as a hacker….

As a punishment I will force myself to read RFC 1035 (http://tools.ietf.org/html/rfc1035).

Over and out….

How to compile VIM under OS X

Mathias Stjernström — Sun, 11 Jan 2009 09:53:31 +0000

Configure and compiling VIM under OS X did not work out-of-the box for me. I did not want to use MacPorts VIM as it’s dependent on ruby (if you like me want that) and I did not find a way of compiling MacPorts VIM against my local ruby.

This post is about how to get VIM compiling on OS X/intel without the use of MacPorts.

1. Configure without specifying architecture

When running configure without specifying architecture everything looks fine but when you run make you get this nice little error.

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./configure --enable-rubyinterp --enable-multibyte --with-features=huge
... stripped output ...
make

Undefined symbols for architecture ppc:
"_main", referenced from:
start in crt1.10.5.o
ld: symbol(s) not found for architecture ppc
collect2: ld returned 1 exit status
lipo: can't open input file: /var/folders/os/osNwawQ0Hreve7NDQEugQ++++TI/-Tmp-//ccD17Dx3.out (No such file or directory)
make[1]: *** [Vim] Error 1
make: *** [first] Error 2

I did not do any Sherlock holmes work to understand this message as I do not need PPC support. I learned that there is a flag called ‘–with-mac-arch‘.

2. configure with specifying architecture

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> ./configure --with-mac-arch=intel --enable-rubyinterp --enable-multibyte --with-features=huge

checking --with-tlib argument... empty: automatic terminal library selection
checking for tgetent in -lncurses... (cached) yes
ncurses library is not usable
checking for tgetent in -ltermlib... no
checking for tgetent in -ltermcap... no
checking for tgetent in -lcurses... no
no terminal library found
checking for tgetent()... configure: error: NOT FOUND!
You need to install a terminal library; for example ncurses.
Or specify the name of the library with --with-tlib.

But as you can see specifying architecture did not even make is trough configure. I tried to specifying –with-tlib and adding LIBS path did not help. I did spend quite some time on this step to solve this one, but no luck here.

3. The working solution.

This became the working solution for me. Not that pretty but it did work

Run ./configure without arch flags.

1	./configure --enable-rubyinterp --enable-multibyte --with-features=huge

When done, edit src/auto/config.mk and remove PPC arch.
And yes! I know editing src/auto/config.mk is not that good and that the file is getting overwritten every time you run configure

1	> vim src/auto/config.mk

on Line 26

1	LDFLAGS = -L. -arch ppc -arch i386 -L/usr/local/lib

Remove the PPC part “-arch ppc”
After removing PPC you can run:

1 2	make sudo make install

I hope this can save someone else some time and i hope this is one of many to come blog posts that involves VIM!

Cheers!

Handling a staging environment with capistrano / rails

Mathias Stjernström — Tue, 06 Jan 2009 20:49:06 +0000

Just before christmas I worked with one of our customers new server cluster or cloud if you may.
This cluster has production nodes and staging nodes and this post is about how to get capistrano to play nice with both production and the staging environment.

I have googled for a solution but all solutions I found where pretty ugly so i decided to create my own. When writing this line I did a test googling just to give an example of a bad example and my first result where the buckblogs blog. A post about a plugin called multistage I do not how I could miss that

But as my solution is so simple I will continue this post and show you anyway.

As usual I have written to much bullshit and I guess that you just want is some code so here you go.

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desc "Run tasks in production enviroment."
task :production do
# Production nodes
role :app, "192.168.1.30"
role :app, "192.168.2.30"
role :db, "192.168.1.30", :primary => true
end

desc "Run tasks in staging enviroment."
task :staging do
# Staging nodes
role :web, "192.168.1.60"
role :app, "192.168.2.60"
role :db, "192.168.1.60", :primary=>true
end

This is all there is to it. Splitting your role definitions into different tasks.
Now you may wonder how you use this when deploying or whatever you do.

Just add those tasks as params to cap.

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cap staging deploy:check
cap staging deploy
# or
cap production deploy:check
cap production deploy

And here is a little bonus

Just to spice this up a bit I added another useful function. A little warning if you are about to deploy to your production environment. When running a big/important site you do not want to deploy into the wrong environment

This is how the final code looks.

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desc "Run tasks in production enviroment."
task :production do
# Prompt to make really sure we want to deploy into prouction
puts "\n\e[0;31m ######################################################################"
puts " #\n # Are you REALLY sure you want to deploy to production?"
puts " #\n # Enter y/N + enter to continue\n #"
puts " ######################################################################\e[0m\n"
proceed = STDIN.gets[0..0] rescue nil
exit unless proceed == 'y' || proceed == 'Y'

# Production nodes
role :app, "192.168.1.30"
role :app, "192.168.2.30"
role :db, "192.168.1.30", :primary => true
end

desc "Run tasks in staging enviroment."
task :staging do
# Staging nodes
role :web, "192.168.1.60"
role :app, "192.168.2.60"
role :db, "192.168.1.60", :primary=>true
end

When this code is used you will get something like the image below.

And thats all there is to it. The only thing that I think is missing is a warning/notice if you do not specify either production/staging. Like it is now you will get an error when capistrano cannot find any valid servers.

Happy deploying!

New version of capistrano_colors released.

Mathias Stjernström — Sun, 04 Jan 2009 15:36:40 +0000

Just released a new version of capistrano_colors. This is a total rewrite from the last version. This post show some of the bigger changes.

The biggest/coolest changes:

You can write your own custom machers and colorize rows that’s special for you.
I found a pretty neat way of making capistrano_colors system wide.
You can hide rows that you do not care for

I do not want to bore you more so I’ll just skip to an example

If you have not already, install capistrano_colors (v.0.5.0)

1	sudo gem install capistrano_colors

The following commands can go into deploy.rb or ~/.caprc depending if you want cc for a single project or system wide.

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require 'capistrano_colors'

capistrano_color_matchers = [
{ :match => /command finished/, :color => :hide, :prio => 10 },
{ :match => /executing command/, :color => :blue, :prio => 10, :attribute => :underscore },
{ :match => /^transaction: commit$/, :color => :magenta, :prio => 10, :attribute => :blink },
{ :match => /git/, :color => :white, :prio => 20, :attribute => :reverse },
]

colorize( capistrano_color_matchers )

The only mandatory options are :match, :colors and :prio.

A fast description of the options:

:match – A regular expression of the row to match.

:color – The color we want on the matching rows.

:prio – What prio should this rule have (higher = more prio)

:attribute – Special effect (:underline, :reverse, :blink)

:level – Specify if this matcher should be bound to some of capistranos log levels (info,debug,…)

A more detailed description can be found at http://github.com/stjernstrom/capistrano_colors/tree/master

As this is a rewrite I would love some feedback.

Thanks!

Put some colors on your capistrano output

Mathias Stjernström — Sat, 20 Dec 2008 23:02:02 +0000

I got so tired of all the messy capistrano output so today I released my first public gem.

The name of the gem is capistrano_colors and the aim of the gem is to put some nice and shiny colors on capistrano output. The gem has only been tested with rails but should work wherever capistrano works.

Keep on reading to see some screenshots!

Just follow the instruction on the github page (http://github.com/stjernstrom/capistrano_colors/) and you will have a colorful output like the second screenshots in no time.

Capistrano output without capistrano_colors

Capistrano output with capistrano_colors

As you can see the output on the second image is much clearer and easier to understand.

Try it out and let me know what you think!

Cheers!

Ruby enterprise edition (REE) on Gentoo failed and some performance experience.

Mathias Stjernström — Mon, 15 Dec 2008 20:44:36 +0000

Today I got the chance to give Ruby Enterprise Edition a try. We are currently working with a really fun new environment and you do not get better opportunities to try new stuff as when you have a complete new environment thats not in production. So we gave REE a shoot. When compiling REE with got in trouble really fast and this post is about the quick fix to solve it and some of our early performance results.

The installation of REE is nothing more that unpacking ruby-enterprise-1.8.6-20081205.tar.gz and the run the installer.

1	tar xzvf ruby-enterprise-1.8.6-20081205.tar.gz

And after that we run

1	./ruby-enterprise-1.8.6-20081205/installer

This is when our problems started.

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chmod -R g+r,o+r,o-w /opt/ruby-enterprise-1.8.6-20081205/lib/ruby
--------------------------------------------
Installing RubyGems...
/opt/ruby-enterprise-1.8.6-20081205/bin/ruby setup.rb --no-ri --no-rdoc
/opt/ruby-enterprise-1.8.6-20081205/bin/ruby: no such file to load -- auto_gem (LoadError)
*** Cannot install RubyGems

This one took some time to find but first I could not understand why auto_gem was not found and also why it tried to load auto_gem when the installation of rubygems is not done.

After a few minutes of thinking and digging i found my environment variable RUBYOPT which was set to -rauto_gem.

1	RUBYOPT=-rauto_gem

This one makes rubygems to autoload when you run something in ruby. I already had this line because i had ruby/rubygems installed before we installed REE. I still want this enviroment but not during the installation so i disabled it by starting the installer like this:

1	RUBYOPT="" ./ruby-enterprise-1.8.6-20081205/installer

Passing the environment variable before the command just sets it for this command.

If you do want this change permanent some digging in /etc found there is no less that 3 files where this variable is set (depending of shells).

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grep -R "RUBYOPT" *
csh.env:setenv RUBYOPT '-rauto_gem'
env.d/10rubygems:RUBYOPT="-rauto_gem"
profile.env:export RUBYOPT='-rauto_gem'

After changing this variable everything worked as expected!

So far our experience with REE is great. With plain old ruby we where running about 15 passenger (mod_rails) instances and we where using around 1.6GB memory. After The ruby enterprise upgrade we are now using 26 instances with only 1.7GB memory. CPU loads when stressing seems to be 50% less with REE and pages load times are much more stable.

You have to take these measurements with a bit of salt because we only had around an hour of testing but they seem pretty impressive so far.

I will get back with more performance data as we play.

Cheers!