Running RCOV, and having it complain about a p articular plugin that it should not have been looking at in the first place, made me want to find a way to exclude it. In my usual practical fashion, I hit google up for a quick way to exclude the unwanted plugin.
Here it is re-posted from Dan Mange’s Blog…
config.plugins = Rails::Initializer.new(config).send(:find_plugins, config.plugin_paths).map {|path| File.basename(path)}
config.plugins -= %W(plugin_one plugin_two)UPDATE: JJ Barrett has an update for Rails 2.x… http://www.jjbarrett.net/archives/plugin-ordering-and-exclusion-in-rails-20
config.plugins = config.plugin_locators.map do |locator|
locator.new(Rails::Initializer.new(config)).plugins
end.flatten.map{|p| p.name.to_sym}
config.plugins -= [:do_not_load_plugin_1, :do_not_load_plugin_2]
‘jaap’ wrote a rake task to convert your Rails application from using Gettext translation into the new I18n support, which is really great!
WARNING: Before you run the new rake task rake gettext_to_i18n:transform, read “So How Do You Fix It?” below
OK, so you’ve followed along in the article and now you want to test out your new localization system. Problem is when you try to start the server up script/server you get this error message:
/Users/cblackburn/Source/ruby/bols/lib/active_support/memoizable.rb:71:in `path': can't modify frozen object (TypeError)…or something similar.
What happened? Since you have frozen Rails and the rake task does not exclude the frozen vendor/rails directory, it modified memoizable.rb in ActiveSupport causing this error.
So How Do You Fix It?
Do one of the following:
- Backup lib/active_support/memoizable.rb before you run the rake task, then restore it after.
- Restore lib/active_support/memoizable.rb using your SCM.
For this project in my case it was
svn revert lib/active_support/memoizable.rbAnother ruby script for your Mac Terminal enjoyment.
I like to work on my Rails projects using at least three command line tabs with their current working directories set to the RAILS_ROOT of my project. This way I can run script/server in one tab, script/console in another and retain one tab to use for various project based work like rake and capistrano tasks. Frequently I found myself manually iterating through each Terminal tab and type ‘cd /Users/…/Source/ruby/projectname’. As we all know personal repetition is the mother of invention. This is what I came up with…
#!/usr/bin/env ruby
require 'rubygems'
require 'appscript'
include Appscript
DEFAULT_PROJ = '.'
project_dir = (ARGV.length > 0) ? ARGV[0] : DEFAULT_PROJ
project_dir = Dir.pwd if project_dir == "."
@term = app('Terminal')
@current_window = @term.windows.first
tab_count = @current_window.tabs.count
for t in 0..tab_count
tab = @current_window.tabs[t]
@term.do_script("cd #{project_dir}", :in => tab)
endSave this file in your personal path as acd.rb
I use this frequently when I switch from one project to another.
Be logged into the directory you want to propagate through all open tabs. Then type: acd.rb which will automatically iterate through each open tab and change the current working directory to the directory you started acd.rb from.
Recently I upgraded my blog here and lost permalinks to several articles, as well as the articles themselves. For that I apologize, if you are looking for something unfound. One such article that I referred to often was ‘Scripting Mac Terminal Using Ruby’. Though this is not the original article, here is a script I recently needed. As will all source code published herein, this is hereby released into the public domain with no warranties of any kind.
This humble little script uses rb-appscript, to change the background color, in Terminal, of the current tab you are running. I like to change colors of tabs to mean different things. For instance, where I am tailing log files – dark green… running irb – dark blue, etc.
Maybe, like me, you stay logged into several machines around the world and want to color-code your tabs based on location.
I called mine colorme.rb. The command line expects a color in this format:
- array: [0,32767,65535] of color values [Red, Green, Blue], 0 to 65535
- string: ‘red’, ‘green’, ‘black’, etc., only the basic colors work as strings
Have fun and let me know if you are doing something interesting with Terminal using Appscript on Ruby.
#!/usr/bin/env ruby
require 'rubygems'
require 'appscript'
include Appscript
_color = (ARGV.length > 0) ? ARGV[0] : 'black'
begin
term = app('Terminal')
current_window = term.windows.first
tab = current_window.tabs.first
current_color = tab.background_color.get
puts "Current Color is: #{current_color.inspect}"
tab.background_color.set(_color)
rescue Exception => e
puts "#{e}"
puts "Usage: colorme.rb array"
puts " ...where array is an array of 3 color values like this [0,32767,65535]"
puts " ...values can be anywhere between 0 and 65535"
puts " ...values, in order, represent 'Red, Green Blue'"
endThought I had posted this last year but can’t seem to find it, so here it is again:
#!/usr/bin/env ruby
require File.dirname(__FILE__) + '/../../config/boot'
# Restart Applicable Passenger Instance
filename = "#{RAILS_ROOT}/tmp/restart.txt"
File.open(filename, 'w') {|f| f.write('restart passenger') }Save this file as: ./scripts/process/reaper, then deploy and it will restart your passenger instance.
UPDATE: As cremes pointed out below, these timings obviously only reflect the version of Ruby I was running at the time. (ruby 1.8.6 (2008-08-11 patchlevel 287) [universal-darwin9.0]). When using any other version of the interpreter, all bets are off.
Another interesting set of timings are the differences between the branching control statements @case-when@ and @if-else@. Here is a quick example:
require 'profilings'
include PeepcodeProfiler
###
# Case-when vs. If-Elsif-Else
###
time_this("case-when using strings") {
x = "10"
case x
when "1"
puts "it is #{x}"
when "2"
puts "it is #{x}"
when "3"
puts "it is #{x}"
when "4"
puts "it is #{x}"
when "5"
puts "it is #{x}"
when "6"
puts "it is #{x}"
when "7"
puts "it is #{x}"
when "8"
puts "it is #{x}"
when "9"
puts "it is #{x}"
when "10"
puts "it is #{x}"
end
}Timings for case when using strings Thread ID: 218880 Total: 0.000113 %self total self wait child calls name 36.28 0.00 0.00 0.00 0.00 10 Kernel#=== (ruby_runtime:0} 31.86 0.00 0.00 0.00 0.00 2 IO#write (ruby_runtime:0} 22.12 0.00 0.00 0.00 0.00 10 String#== (ruby_runtime:0} 9.73 0.00 0.00 0.00 0.00 1 Kernel#puts (ruby_runtime:0} 0.00 0.00 0.00 0.00 0.00 0 PeepcodeProfiler#time_this (./profilings.rb:8}
…and again the faster @if-elsif-else@:
time_this("if-elsif-else using strings") {
x = "10"
if x == "1"
puts "it is #{x}"
elsif x == "2"
puts "it is #{x}"
elsif x == "3"
puts "it is #{x}"
elsif x == "4"
puts "it is #{x}"
elsif x == "5"
puts "it is #{x}"
elsif x == "6"
puts "it is #{x}"
elsif x == "7"
puts "it is #{x}"
elsif x == "8"
puts "it is #{x}"
elsif x == "9"
puts "it is #{x}"
elsif x == "10"
puts "it is #{x}"
else
puts "it is #{x}"
end
}Timings for if elsif else using strings Thread ID: 218880 Total: 0.000049 %self total self wait child calls name 46.94 0.00 0.00 0.00 0.00 10 String#== (ruby_runtime:0} 30.61 0.00 0.00 0.00 0.00 2 IO#write (ruby_runtime:0} 22.45 0.00 0.00 0.00 0.00 1 Kernel#puts (ruby_runtime:0} 0.00 0.00 0.00 0.00 0.00 0 PeepcodeProfiler#time_this (./profilings.rb:8}
OK, obviously the @case-when@ version is slower because it does a compare for each value using the @===@ Kernel operator, which in turn calls the correct @==@ operator for the value type. Whereas the @if-elseif-else@ version doesn’t incur the overhead of the Kernel triple-equal operator for each comparison.
So I wonder if the same thing happens with a different object type:
time_this("case when using integers") {
x = 10
case x
when 1
puts "it is #{x}"
when 2
puts "it is #{x}"
when 3
puts "it is #{x}"
when 4
puts "it is #{x}"
when 5
puts "it is #{x}"
when 6
puts "it is #{x}"
when 7
puts "it is #{x}"
when 8
puts "it is #{x}"
when 9
puts "it is #{x}"
when 10
puts "it is #{x}"
end
}Timings for case when using integers Thread ID: 218880 Total: 0.000104 %self total self wait child calls name 46.15 0.00 0.00 0.00 0.00 10 Kernel#=== (ruby_runtime:0} 19.23 0.00 0.00 0.00 0.00 9 Fixnum#== (ruby_runtime:0} 15.38 0.00 0.00 0.00 0.00 2 IO#write (ruby_runtime:0} 15.38 0.00 0.00 0.00 0.00 1 Kernel#puts (ruby_runtime:0} 3.85 0.00 0.00 0.00 0.00 1 Fixnum#to_s (ruby_runtime:0} 0.00 0.00 0.00 0.00 0.00 0 PeepcodeProfiler#time_this (./profilings.rb:8}
Hmmm, bad news. Here we see the Kernel @===@ operator in the call stack again.
time_this("if elsif else using integers") {
x = 10
if x == 1
puts "it is #{x}"
elsif x == 2
puts "it is #{x}"
elsif x == 3
puts "it is #{x}"
elsif x == 4
puts "it is #{x}"
elsif x == 5
puts "it is #{x}"
elsif x == 6
puts "it is #{x}"
elsif x == 7
puts "it is #{x}"
elsif x == 8
puts "it is #{x}"
elsif x == 9
puts "it is #{x}"
elsif x == 10
puts "it is #{x}"
else
puts "it is #{x}"
end
}Timings for if elsif else using integers Thread ID: 218880 Total: 0.000057 %self total self wait child calls name 50.88 0.00 0.00 0.00 0.00 10 Fixnum#== (ruby_runtime:0} 26.32 0.00 0.00 0.00 0.00 2 IO#write (ruby_runtime:0} 15.79 0.00 0.00 0.00 0.00 1 Kernel#puts (ruby_runtime:0} 7.02 0.00 0.00 0.00 0.00 1 Fixnum#to_s (ruby_runtime:0} 0.00 0.00 0.00 0.00 0.00 0 PeepcodeProfiler#time_this (./profilings.rb:8}
Interesting. Even for a different object type, the @case@ statement incurs the overhead of the Kernel @===@ operator.
Now I’m not saying to always avoid the @case@ statement. It is really a judgement call. I typically prefer cleaner code over slight optimization benefits. However, in this case (no pun intended) @if-elsif-else@ is consistently about twice as fast as the @case-when@ statement. You be the judge for your own particular situation.
Take a look “here”:/2008/11/18/the-peepcode-profiler for the “Peepcode profiler”:/2008/11/18/the-peepcode-profiler that we use when doing our metrics. If you come up with interesting metrics please let us know. We are happy to publish them here, giving you the credit, or link to them from here.
Happy Hacking!!!
UPDATE: Peter Wagenet brought up a good point, noting that our metrics did not completely determine if the slower @case@ statement is indeed slower merely because it uses @===@ operator, or if there is more overhead involved with @case@. So here is our test…
time_this("if elsif else using integers with ===") {
x = 10
if x === 1
puts "it is #{x}"
elsif x === 2
puts "it is #{x}"
elsif x === 3
puts "it is #{x}"
elsif x === 4
puts "it is #{x}"
elsif x === 5
puts "it is #{x}"
elsif x === 6
puts "it is #{x}"
elsif x === 7
puts "it is #{x}"
elsif x === 8
puts "it is #{x}"
elsif x === 9
puts "it is #{x}"
elsif x === 10
puts "it is #{x}"
else
puts "it is #{x}"
end
}Timings for if elsif else using integers with === Thread ID: 218880 Total: 0.000081 %self total self wait child calls name 50.62 0.00 0.00 0.00 0.00 10 Kernel#=== (ruby_runtime:0} 23.46 0.00 0.00 0.00 0.00 9 Fixnum#== (ruby_runtime:0} 11.11 0.00 0.00 0.00 0.00 1 Kernel#puts (ruby_runtime:0} 11.11 0.00 0.00 0.00 0.00 2 IO#write (ruby_runtime:0} 3.70 0.00 0.00 0.00 0.00 1 Fixnum#to_s (ruby_runtime:0} 0.00 0.00 0.00 0.00 0.00 0 PeepcodeProfiler#time_this (./profilings.rb:8}
After running the test several times I have determined that using the @===@ operator is obviously, and consistently slower than @==@ alone. However, the @case@ statement is consistently slower still, than @if-elsif@ using the @===@ operator. Therefore @case@ does incur overhead beyond the simple use of @===@ by about 20%.
My friend and colleague Peter Wagenet has written an “excellent article”:http://in.finitu.de/2008/11/22/pragmatic-programming about the true meaning of “pragmatic programming”, and how to achieve it. Check it out!
A few people have asked me for the module I’ve been using to profile my code in my “Double Quotes vs. Single Quotes”:/2008/06/10/ruby-performance-use-double-quotes-vs-single-quotes article. It is merely a wrapper around “RubyProf”:http://ruby-prof.rubyforge.org/, dead simple and nothing worth commenting on, but since some keep asking – here it is:
require 'rubygems'
require 'ruby-prof'
module PeepcodeProfiler
def time_this(comment, &block)
RubyProf.measure_mode = RubyProf::PROCESS_TIME
RubyProf.start
yield
result = RubyProf.stop
puts "\nTimings for #{comment}"
printer = RubyProf::FlatPrinter.new(result)
printer.print(STDOUT, 0)
end
endI wrote this for some work on a “Scaling Rails” minibook for “Peepcode”:http://peepcode.com/, which I seem to be unable to finish. I hope Geoffrey forgives me.
Between the time your migration files get generated and deploying to production with your new application you will likely need to add indexes to one or more of your tables. How do you know which tables need indexes and which fields in those tables to index?
Here are some tips to help figure out where the likely bottlenecks will occur with regard to your database tables:
- Always index @*id@ foreignkey fields. Let’s say you have 2 tables, @users@ and @addresses@. You may have migration file code in @./db/migrate@ that looks like this:
...
def self.up
create_table "users", :force => true do |t|
t.column :login, :email :string
end
end
... ...
def self.up
create_table "addresses", :force => true do |t|
t.column :user_id :integer
t.column :address :string
end
end
...You will always want to index the foreignkey @userid@, with few exceptions. So simply add the @add_index@ line like this:
...
def self.up
create_table "addresses", :force => true do |t|
t.column :user_id :integer
t.column :address :string
end
add_index "addresses", :user_id
end
...This will facilitate much faster associations when you lookup related models like this view code:
<%=h user.address.address %>
# OR as the case may be...
<%=h address.user.email %>- As a rule of thumb index any column for which you will be using to lookup a row or set of rows. For example, if you will be doing something like this:
u = User.find_by_email('test@example.com')… then you will want to index the email field.
- Run explain plans on your associations to determine where indexes would benefit the queries. Now this one is more tricky unless you know about the query_analyzer plugin. This nifty little tool will automatically dump out explain plans into your logfiles in development mode that look like this example from the README file:
# development.log P Load (0.008669) => SELECT p.* FROM p INNER JOIN d ON p.id = d.p_id WHERE (d.p_id = 2 AND ((d.type = 'P'))) Analyzing P Load select_type | key_len | type | Extra | id | possible_keys | rows | table | ref | key ---------------------------------------------------------------------------------------------------- SIMPLE | | ALL | Using where | 1 | | 74 | d | | SIMPLE | 4 | eq_ref | Using where | 1 | PRIMARY | 1 | p | d.p_id | PRIMARY
Now what this tells you is that the table @d@ is missing an index because MySQL is having to look at “ALL” the records. Whenever you see a @type@ of @ALL@ and/or @possible_keys@ is empty it should be a red flag telling you to index something.
If we had followed tips 1 and 2 this explain plan would be much different, showing reference types of @ref@ and @eq_ref@ which is typically a good thing.
For more information see the README file here: http://agilewebdevelopment.com/plugins/query_analyzer.
If you are getting an error message like this:
ActiveRecord::StatementInvalid: Mysql::Error: Table configurable_settings doesn't exist
… when trying to use Jacob Radford’s http://agilewebdevelopment.com/plugins/acts_as_configurable
Just do this:
./script/console development
ConfigurableSetting.create_table
Of course replace ‘development’ above with whatever environment you need.