Capistrano variables

Posted by Dr Nic on April 10, 2007 and blessed with 9 comments

Here’s an example of how you can pass variables to your capistrano actions via the cap command.

So, the above action could be called as follows:

cap log
cap log -s lines=1000
cap log -s rails_env=test

For reference, you pass values to Rake tasks via environment variables:

rake db:migrate RAILS_ENV=test

Inside the db:migrate task, you’d retrieve the value ‘test’ via ENV['RAILS_ENV'].

And further more, this then compares to how you'd normally pass option values into normal command-line apps:

tail -n 1000 log/production.log

Who said the unix command line wasn't easy peasy. Bah.

Related posts:

  1. Magic Multi-Connections: A “facility in Rails to talk to more than one database at a time” At this point in time there’s no facility in Rails...
Trackbacks

Use this link to trackback from your own site.

Comments

Leave a response

  1. atmos Wed, 11 Apr 2007 05:20:26 UTC

    Nice! I hadn’t used that before.

  2. topfunky Wed, 11 Apr 2007 06:37:08 UTC

    Actually, you don’t even need the configuration.variables part! It’s almost as magic as Dr. Nic’s models.

    Anything passed with dash-s becomes a local variable in your Capistrano recipes.

  3. Dr Nic Wed, 11 Apr 2007 06:53:25 UTC

    @topfunky – that’s how I thought it should work too. But it wasn’t working, hence hunting down configuration.variables hash.

    Here’s the same action using local variables:

    task :log do
  lines ||= 100
  rails_env ||= 'production'
  # lines     = configuration.variables[:lines] || 100
  # rails_env = configuration.variables[:rails_env] || 'production'
  env   = ENV['RAILS_ENV'] || 'production'
  run "tail -n #{lines} #{deploy_to}/#{shared_dir}/log/#{rails_env}.log" do |ch, stream, out|
    puts out
  end
end

    But when I run cap log -s lines=10 it still looks for the default 100.

    I’ll ping it to the capistrano mailing list/Jamis and see if anyone can reproduce this.

  4. choonkeat Wed, 11 Apr 2007 07:17:29 UTC

    I have a “ask” method in my capistrano instead: http://pastie.caboo.se/52993

    So I’ll do

    ask :server_port, "Port number", "3000"
    puts server_port

    If the value is given at command line via -S server_port=5000 then it won’t ask, otherwise prompt.

  5. Sergio Espeja Wed, 11 Apr 2007 10:48:17 UTC

    Very useful!

    This is a good capistrano variables example and also a very useful recipe!

    I’ve started using this recipe and blogged it in spanish at my blog: http://spejman.blogspot.com/2007/04/logs-del-servidor-con-capistrano.html

    Thanks for your post!

  6. Dr Nic Wed, 11 Apr 2007 13:07:45 UTC

    @all – see http://groups.google.com/group/capistrano/browse_thread/thread/d4d30393b6f41605 for discussion about the mysterious #lines variable/method.

  7. Wayne Seguin Sat, 14 Apr 2007 15:59:02 UTC

    Nic,

    Please read my reply:

    http://groups.google.com/group/capistrano/browse_thread/thread/d4d30393b6f41605

    Thanks,
    ~Wayne

  8. topfunky Mon, 09 Jul 2007 22:44:21 UTC

    In Cap2 this appears to be just ‘variables’ instead of ‘configuration.variables’.

  9. sesli sohbet Wed, 08 Jul 2009 03:39:01 UTC

    In Cap2 this appears to be just ‘variables’ instead of ‘configuration.variables’.

Comments