Running Rails 3.1.1 on Heroku

Heroku officially supports rails 3.1.1 on their Cedar stack now, unfortunately, you may still fail on deploy. The trouble maker is the assets:precompile rake task in rails 3.1. Heroku runs 'rake assets:precompile' for you when deploy, at a time many application dependencies, e.g. database server, redis, are NOT ready, so if there's any database/redis/any-other-not-ready-dependency use in your rails initialization process, assets:precompile will fail.

The tricky thing is, even you know the underlying theory, it's hard to find the exact place caused the problem, because heroku deployment do not use '--trace' flag when running precompile task, the limited error output is almost useless; and rails initialization process walks through so many files it's stupid to check them one by one.

For example, this is the error I got today when I deploy to heroku:

rake aborted!
bad URI(is not URI?):

Can you spot the broken code with so few information? I can't ... Fortunately, we can ask rake to give detail error stack without passing it '--trace' option, by adding this line in your Rakefile:

Rake.application.options.trace = true if %w(staging production).include?(Rails.env)

Then another problem pops up, I now found the broken code, how to fix it? Since the broken code uses something that is not ready when assets:precompile task running, an easy way would be:

# in Rakefile
if %w(staging production).include? Rails.env
$heroku_deploying = true if File.basename($0) == 'rake' && ARGV.include?('assets:precompile')
end

# in some initializers:
# reference to UsersController will trigger operation on database
provider :identity, :fields => [:name, :email, :nickname], :on_failed_registration => UsersController.action(:new) unless $heroku_deploying

With this duct tape kind fix, you may have $heroku_deploying scattered in your code .. it's ugly but works. Let me know if you have better idea :-)

[ANN] Rubytest.vim 1.1.0 Released!

There're two major changes in this release:

* Remember last run: <leader>l to run last run test (thanks John Weir!)

* Default support to rspec2. You need to customize g:rubytest_cmd_spec to work with rspec 1.*

Download [1][2] and copy/overwrite to install/upgrade!

1. http://www.vim.org/scripts/script.php?script_id=2612

2. http://github.com/janx/vim-rubytest/tree/master

ZJU the Champions of ACM-ICPC World Finals 2011!

Finally, finally, congratulations ~ Rankings

Angry Terminal

Last night I got the idea that using different colors in shell prompt to tell the user about the result of last command executed, e.g. red for failed execution and green for success.

It's really easy to do that in the ultimate shell, all I need is a function and a prompt using it:

function prompt_base_color() {
 if [[ $? == "0" ]]; then
   echo $PR_GREEN
 else
   echo "$PR_RED"
 fi
}

PROMPT='$PR_SET_CHARSET$PR_STITLE${(e)PR_TITLEBAR}$(prompt_base_color)%D{%H:%M} $PR_GREEN%~ $PR_RED$(git_prompt_info)$PR_NO_COLOUR'

It make your terminal look like this:



Then I realized I can go one step further to help terminal express her feeling, I always feel she is angry with me.

So I changed the function a bit, like this:

function prompt_base_color() {
 if [[ $? == "0" ]]; then
   echo $PR_GREEN
 else
   txt=`cat ~/.zsh/my_ass.txt`
   echo "$txt\n$PR_RED"
 fi
}

And put the feeling in a file by `cowsay My ASS > ~/.zsh/my_ass.txt`.

Now Miss Terminal can tell me what she thinks when I do something wrong!