pastbedti.me » Rails

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!

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….

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!

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!

The developers behind Newsdesk have a weblog!

Mathias Stjernström — Tue, 25 Nov 2008 19:21:21 +0000

Finally my friends at newsdesk have a blog. They have started off real good with a comparison of three ruby wrappers for Google charts.

I have great expectations from the newsdesk developers blog. If you are a Ruby and Rails developer you should definitely keep and eye on them!

Redirecting with nginx

Mathias Stjernström — Wed, 21 May 2008 17:22:37 +0000

Today one of our server got in trouble with an ACE encoded IDN domain. The problem seemed to be rails in combination with nginx’s X-Sendfile feature. The result became that when accessing the site trough the IDN domain x-senfile did not send any files….

Our quick and dirty solution (until we have found the source/or solved the problem) became redirecting all traffic from the IDN domain to the domain without strange-swedish-characters.

With nginx this is as simple as in most webservers just put the following code before you original server configuration in nginx.conf.

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server {
server_name xn--svenskdomn-y5a.se www.xn--svenskdomn-y5a.se;
rewrite ^(.*) http://www.svenskdoman.se$1 permanent;
}

And Bowang! All requests to www.svenskdomän.se will be redirected to www.svenskdoman.se.

Domain names have been changed to protect the innocent

Cheers!