Capistrano 2 Recipe for Dreamhost Shared Hosting and mod_rails

June 30th, 2008

Introduction

I could not find an updated documentation on how to setup properly a rails application on Dreamhost, so I thought I'd share the information I gathered.. First off, thanks to the Phusion team, with Passenger (a.k.a. mod_rails), it's now very convenient, easy, and cheap to run a rails application on Dreamhost.

Also, special thanks to Todd Huss for discovering the multi dreamhost user hack. Basically, you need to run each of your rails application on Dreamhost under a different shell user. Their process monitor, will start killing your processes when the total memory per user exceeds 200 MB of virtual memory (VSZ).

So here's the guide, even perfect newbees and skript-kiddies should be able to follow :

The complete step by step

INFO : Let Capistrano create the directory structure on the server BEFORE you set the public dir of your application in the edit domain section of the Control Panel. This will avoid you conflicts when Capistrano attemps to create the symlinks.

  1. First, configure your new rails application using Dreamhost Control Panel :

    1. Create a new repository for your application (screenshot)

    2. Create a new shell / SSH user (read why here) with the same name as your application (screenshot)

    3. Create a new database (screenshot)

  2. Add your application to your repository
    1. Create your rails skeleton (if it's done yet), on your local machine (assuming you use *nix, but should be similar on Windows) 
      

      $ rails myrailsapp --freeze
    2. Add your application to the repository 
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      $ cd myrailsapp
$ svn mkdir http://svn.myrailsappdomain/myrails/trunk
$ svn checkout http://svn.myrailsappdomain/myrails/trunk ./
$ svn add  *
$ svn commit
    3. Exclude database configuration, temporary files, and any user upload directory from the source control : 
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      $ svn copy config/database.yml config/database.yml.example
$ svn remove config/database.yml -f
$ svn propset svn:ignore "database.yml" config/
$ svn remove tmp/*
$ svn propset svn:ignore "*" tmp/
# If you need to share unversionned user-uploaded files, between deploys :
$ mkdir public/uploads
$ svn add public/uploads
$ svn propset svn:ignore "*" public/uploads/
$ svn remove log/*
$ svn propset svn:ignore "*" log/
$ svn remove db/*.sqlite3
$ svn propset svn:ignore "*.sqlite3" db/
$ svn commit
  3. Next, create the Capistrano recipe :
    1. Create recipe skeleton : 
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      $ cd /path/to/your/myrailsapp
$ capify .
[add] writing `./Capfile'
[add] writing `./config/deploy.rb'
[done] capified!
    2. Replace the content of config/deploy.rb with the following : 
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      #############################################################
## General
#############################################################
set :application, "myrailsapp"


#############################################################
## Servers 
#############################################################
set :use_sudo, false    # Dreamhost does not support sudo
set :user, application  # Dreamhost SSH User
set :domain, "myrailsapp.domain.com"

server domain, :app, :web
role :db, domain, :primary => true


#############################################################
## Subversion
#############################################################
set :scm, :subversion
set :scm_user, application   # Sets 'my_svn_user' instead, if you are using different name than your app.
set :scm_auth_cache, true  # Prompts for password once
set :scm_password, Proc.new { Capistrano::CLI.password_prompt("SCM password for #{scm_user}:") }
set :repository,  "http://svn.myrailsappdomain/#{application}/trunk"
set :deploy_to, "/home/#{user}/#{domain}"
# keeps a local checkout of the repository on the server to get faster deployments
set :deploy_via, :remote_cache


#############################################################
## Tasks
#############################################################

namespace :deploy do
  desc "Restart Application (using tmp/restart.txt)"
  task :restart_passenger do
    run "touch #{current_path}/tmp/restart.txt"
  end

  desc "Restarts your application."
  task :restart do
    restart_passenger
  end

  desc "Link shared files"
  #task :before_symlink do
  before :symlink do
    run "rm -drf #{release_path}/public/uploads"
    run "ln -s #{shared_path}/uploads #{release_path}/public/uploads"
    run "rm -f #{release_path}/config/database.yml"
    run "ln -s #{shared_path}/database.yml #{release_path}/config/database.yml"
  end
end
  4. Then, prepare the directory structure on the server :
    1. Create the Capistrano structure (releases/, shared/), by typing this on your local machine : 
      

      $ cap deploy:setup
    2. Login to your server to manually create your shared directories and files (if any) 
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      $ ssh myrailsapp.domain.com
[tootsie]$ cd myrailsapp/shared
    3. Configure your database on the server (you don't want this file in your repository) : 
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      # config/database.yml

development:
  adapter: sqlite3
  database: db/development.sqlite3
  timeout: 5000

test:
  adapter: sqlite3
  database: db/test.sqlite3
  timeout: 5000

production:
  adapter: mysql
  encoding: utf8
  database: myrailsapp
  username: myrailsapp
  password: [your_db_password]
  host: mysql.[myrailsapp.domain].com
  timeout: 5000
    4. Create your upload directory (OPTIONAL) : 
      

      [tootsie]$ mkdir uploads
  5. Deploy your application. Note : it will only prompt for your SVN password at the first deploy. 
    

    $ cap deploy
  6. And finally the most important, configure your domain like this :

[UPDATE 2008/07/01]

If you need to install custom gems on your account, you can find more info here, here and here.

References

  1. http://labs.peritor.com/webistrano/wiki/ConfigurationParameter
  2. http://groups.google.ca/group/capistrano/browse_thread/thread/6ef7c7c212547eab (for scm_password)
  3. http://groups.google.com/group/capistrano/browse_thread/thread/ae7b16a16abf4e5d (for task hookups with namespaces)
  4. http://groups.google.com/group/capistrano/web/deploying-on-dreamhost
  5. http://gabrito.com/post/ruby-on-rails-dreamhost-plugin
  6. http://www.railsforum.com/viewtopic.php?id=8118
  7. Dreamhost Wiki : Capistrano
  8. Dreamhost Wiki : Ruby_on_Rails
  10. Capistrano Manual
Posted by david Filed in Linux, Ruby on Rails

7 Responses to “Capistrano 2 Recipe for Dreamhost Shared Hosting and mod_rails”

  1. David Says:
    July 30th, 2008 at 12:41 AM Hi David, I'm really glad that you posted this procedure, and I've been trying to execute it. When attempting to deploy, I receive the following message: * executing 'deploy' * executing 'deploy:update' ** transaction: start * executing 'deploy:update_code' Server refused our key Could you help to try to identify why this error occurred? A person checking the auth.log said that he didn't see any failed authentication keys, and I've been able to connect through putty with keys. Thank you! David
  2. David On Laptop Says:
    August 28th, 2008 at 05:11 AM Hi David, You have to tell Capistrano to encrypt the communication with your private RSA key. Set the ssh_options[:keys] to point to your private key on your local machine. Add this in the recipe file: ssh_options[:verbose] = :debug ssh_options[:keys] = 'path/to/my/ssh/key/id.rsa' Comment the :verbose line once your setup is working. Note, that you first need, to add your public key on your Dreamhost account in $HOME/.ssh/authorized_keys. Which you probably have already done, if Putty is working for you. if it still is not working, try adding these 2 lines: ssh_options[:port] = 22 ssh_options[:user] = 'ssh_user' Hope that helps!
  3. Deariehita Says:
    September 22nd, 2008 at 09:45 PM nice work, guy
  4. Tak Says:
    November 25th, 2008 at 10:44 AM I am following your tutorial and got this error trying to add my app to a repository doing - svn checkout. 'svn not recognized as internal or external command'. I am on Windows XP and rails 2.2.2. Do I have to install gem for svn command to work?
  5. David On Laptop Says:
    December 4th, 2008 at 06:03 AM @Tak : Yes, you need to install subversion (SVN) on your machine. You can download an excellent GUI (visual interface) for Windows from Tigris : lhttp://tortoisesvn.tigris.org/ . AND/OR you can simply use the command-line version (to use in the DOS prompt) : http://subversion.tigris.org/
  6. richy Says:
    December 5th, 2008 at 02:11 PM hi! tnx for this post! i have a small problem with it: when i created i subversion project in the dh panel (svnproj.dreamhosters.com) it wont create additional folder structure like svnproj.dreamhosters.com/trunk etc... i think the trunk folder is needed for svn to work - so: should i add folders manually?
  7. David On Laptop Says:
    December 9th, 2008 at 07:12 AM @Richy : You are right the folders trunk, branches, tags are NOT created by default, i forgot about that. These folders are a simply regular folders following a naming convention; you have to create them manually. They are NOT required by Subversion to work, but it is a good practise to use a trunk subfolder, in case later on you start branching (svn book, chapter 6 i think). I updated the article, all you need to do is "svn mkdir http://svn.myrailsappdomain/myrails/trunk" before the initial checkout.

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