These answers assume you know what a DSL is, or are familiar with Make or Ant. If that&#39;s not the case, here&#39;s a (perhaps grossly oversimplified answer):

[Rake](http://rake.rubyforge.org/) is a tool you can use with [Ruby](https://www.ruby-lang.org) projects. It allows you to use ruby code to define &quot;tasks&quot; that can be run in the command line.

Rake can be [downloaded and included](http://rake.rubyforge.org/#label-Installation) in ruby projects as a ruby gem.

Once installed, you define tasks in a file named &quot;[Rakefile](http://rake.rubyforge.org/doc/rakefile_rdoc.html)&quot; that you add to your project.

We call it a &quot;build tool&quot; because Rake comes with some libraries that make it easy to do tasks that are common during the build/deploy process, like [file operations](http://martinfowler.com/articles/rake.html#FileTasks) (creating, deleting, renaming, &amp; moving files), publishing sites via [FTP](http://ruby-doc.org/stdlib-2.0.0/libdoc/rake/rdoc/Rake/FtpUploader.html)/[SSH](http://ruby-doc.org/stdlib-2.0.0/libdoc/rake/rdoc/Rake/SshDirPublisher.html), and [running tests](http://rake.rubyforge.org/classes/Rake/TestTask.html). 

For more information, here&#39;s the project documentation: http://rake.rubyforge.org/

Try Martin Fowler&#39;s article on Rake for more information:

http://martinfowler.com/articles/rake.html

His pre-amble is:

&gt; Rake is a build language, similar in
&gt; purpose to make and ant. Like make and
&gt; ant it&#39;s a Domain Specific Language,
&gt; unlike those two it&#39;s an internal DSL
&gt; programmed in the Ruby language. In
&gt; this article I introduce rake and
&gt; describe some interesting things that
&gt; came out of my use of rake to build
&gt; this web site: dependency models,
&gt; synthesized tasks, custom build
&gt; routines and debugging the build
&gt; script.

There is more information available on or linked from the project&#39;s home page as well:

http://rake.rubyforge.org/

[Rake][1] is an implementation of [dependency-based declarative programming][2] in the [Ruby Programming Language][3]. Basically, Rake is to Ruby what [Make][4] is to C, with the notable difference, that Make is an external [DSL][5], while Rake is an internal DSL.

  [1]: http://Rake.RubyForge.Org/
  [2]: http://MartinFowler.Com/articles/rake.html#DependencyBasedProgramming
  [3]: http://Ruby-Lang.Org/
  [4]: http://OpenGroup.Org/onlinepubs/009695399/utilities/make.html
  [5]: http://MartinFowler.Com/bliki/DomainSpecificLanguage.html

Rake lets you execute Ruby code through a nice namespace api. An example is &lt;tt&gt;rake db:migrate&lt;/tt&gt;. You can run tasks automatically before and after other tasks. That is all.

Is there a way to configure log4j so that it outputs different levels of logging to different appenders?  

I&#39;m trying to set up multiple log files.  The main log file would catch all INFO and above messages for all classes.  (In development, it would catch all DEBUG and above messages, and TRACE for specific classes.)  

Then, I would like to have a separate log file.  That log file would catch all DEBUG messages for a specific subset of classes, and ignore all messages for any other class.  

Is there a way to get what I&#39;m after?

Creating multiple log files of different content with log4j

I would like to port my C/C++ apps to OS X. 

I don&#39;t have a Mac, but I have Linux and Windows. Is there any tool for this?

How to Compile for OS X in Linux or Windows?

In simple terms, what does Rake do? What purposes does it have? I understand it&#39;s a build tool but I&#39;m looking a bit more detail.

What exactly is Rake?

<p>In simple terms, what does Rake do? What purposes does it have? I understand it's a build tool but I'm looking a bit more detail.</p>


I don&#39;t want to add `schema.rb` to `.gitignore`, because I want to be able to load a new database schema from that file.  However, keeping it checked in is causing all sorts of spurious conflicts that are easily resolved by a fresh `db:migrate:reset`.

Basically I want a way to:

 2. Keep schema.rb in the repository for deploy-time database setup
 3. Keep schema.rb in &#39;.gitignore&#39; for general development

There would be one or two people responsible for updating `schema.rb` and knowing that it was correct.

Is there a way I can have my cake and eat it, too?


What is the preferred way to manage schema.rb in git?

This seems like a really simple question but I haven&#39;t seen it answered anywhere.

In rails if you have:

    class Article &lt; ActiveRecord::Base 
      has_many :comments 
    end 
    class Comments &lt; ActiveRecord::Base 
      belongs_to :article 
    end

Why can&#39;t you order the comments with something like this:

    @article.comments(:order=&gt;&quot;created_at DESC&quot;)

Named scope works if you need to reference it a lot and even people do stuff like this:

    @article.comments.sort { |x,y| x.created_at &lt;=&gt; y.created_at }

But something tells me it should be simpler.  What am I missing?

How do I automatically sort a has_many relationship in Rails?

I seem to be unable to use the ActiveRecord::Base.find option :order for more than one column at a time. 

 For example, I have a &quot;Show&quot; model with date and attending columns.

If I run the following code:

    @shows = Show.find(:all, :order =&gt; &quot;date&quot;)

I get the following results:

    [#&lt;Show id: 7, date: &quot;2009-04-18&quot;, attending: 2&gt;, 
     #&lt;Show id: 1, date: &quot;2009-04-18&quot;, attending: 78&gt;, 
     #&lt;Show id: 2, date: &quot;2009-04-19&quot;, attending: 91&gt;, 
     #&lt;Show id: 3, date: &quot;2009-04-20&quot;, attending: 16&gt;,
     #&lt;Show id: 4, date: &quot;2009-04-21&quot;, attending: 136&gt;]

If I run the following code: 

    @shows = Show.find(:all, :order =&gt; &quot;attending DESC&quot;)

    [#&lt;Show id: 4, date: &quot;2009-04-21&quot;, attending: 136&gt;,
     #&lt;Show id: 2, date: &quot;2009-04-19&quot;, attending: 91&gt;,
     #&lt;Show id: 1, date: &quot;2009-04-18&quot;, attending: 78&gt;,
     #&lt;Show id: 3, date: &quot;2009-04-20&quot;, attending: 16&gt;,
     #&lt;Show id: 7, date: &quot;2009-04-18&quot;, attending: 2&gt;]

But, if I run:

    @shows = Show.find(:all, :order =&gt; &quot;date, attending DESC&quot;)

OR 

    @shows = Show.find(:all, :order =&gt; &quot;date, attending ASC&quot;)

OR 

    @shows = Show.find(:all, :order =&gt; &quot;date ASC, attending DESC&quot;)


I get the same results as only sorting by date:

     [#&lt;Show id: 7, date: &quot;2009-04-18&quot;, attending: 2&gt;, 
     #&lt;Show id: 1, date: &quot;2009-04-18&quot;, attending: 78&gt;, 
     #&lt;Show id: 2, date: &quot;2009-04-19&quot;, attending: 91&gt;, 
     #&lt;Show id: 3, date: &quot;2009-04-20&quot;, attending: 16&gt;,
     #&lt;Show id: 4, date: &quot;2009-04-21&quot;, attending: 136&gt;]

Where as, I want to get these results:

    [#&lt;Show id: 1, date: &quot;2009-04-18&quot;, attending: 78&gt;,
    #&lt;Show id: 7, date: &quot;2009-04-18&quot;, attending: 2&gt;, 
     #&lt;Show id: 2, date: &quot;2009-04-19&quot;, attending: 91&gt;, 
     #&lt;Show id: 3, date: &quot;2009-04-20&quot;, attending: 16&gt;,
     #&lt;Show id: 4, date: &quot;2009-04-21&quot;, attending: 136&gt;]

This is the query being generated from the logs:

    [4;35;1mUser Load (0.6ms)[0m   [0mSELECT * FROM &quot;users&quot; WHERE (&quot;users&quot;.&quot;id&quot; = 1) LIMIT 1[0m
    [4;36;1mShow Load (3.0ms)[0m   [0;1mSELECT * FROM &quot;shows&quot; ORDER BY date ASC, attending DESC[0m
    [4;35;1mUser Load (0.6ms)[0m   [0mSELECT * FROM &quot;users&quot; WHERE (&quot;users&quot;.&quot;id&quot; = 1) [0m


Finally, here is my model:

      create_table &quot;shows&quot;, :force =&gt; true do |t|
        t.string   &quot;headliner&quot;
        t.string   &quot;openers&quot;
        t.string   &quot;venue&quot;
        t.date     &quot;date&quot;
        t.text     &quot;description&quot;
        t.datetime &quot;created_at&quot;
        t.datetime &quot;updated_at&quot;
        t.decimal  &quot;price&quot;
        t.time     &quot;showtime&quot;
        t.integer  &quot;attending&quot;,   :default =&gt; 0
        t.string   &quot;time&quot;
      end

What am I missing?  What am I doing wrong?



**UPDATE: Thanks for all your help, but it seems that all of you were stumped as much as I was.  What solved the problem was actually switching databases.  I switched from the default sqlite3 to mysql.**  



Rails Active Record find(:all, :order =&gt; ) issue

My question is similar to [this one](https://stackoverflow.com/questions/658689/how-to-associate-labels-with-radio-buttons)
but for a Rails app.

I have a form with some radio buttons, and would like to associate labels with them. The `label` form helper only takes a form field as a parameter, but in this case I have multiple radio buttons for a single form field. The only way I see to do it is to manually create a label, hard coding the ID that is auto generated for the radio button. Does anyone know of a better way to do it?

For example:

    &lt;% form_for(@message) do |f| %&gt;
    	&lt;%= label :contactmethod %&gt;
    	&lt;%= f.radio_button :contactmethod, &#39;email&#39;, :checked =&gt; true %&gt; Email
    	&lt;%= f.radio_button :contactmethod, &#39;sms&#39; %&gt; SMS
    &lt;% end %&gt;

This generates something like:

    &lt;label for=&quot;message_contactmethod&quot;&gt;Contactmethod&lt;/label&gt;
    &lt;input checked=&quot;checked&quot; id=&quot;message_contactmethod_email&quot; name=&quot;message[contactmethod]&quot; value=&quot;email&quot; type=&quot;radio&quot;&gt; Email
    &lt;input id=&quot;message_contactmethod_sms&quot; name=&quot;message[contactmethod]&quot; value=&quot;sms&quot; type=&quot;radio&quot;&gt; SMS

What I want:

    &lt;input checked=&quot;checked&quot; id=&quot;message_contactmethod_email&quot; name=&quot;message[contactmethod]&quot; value=&quot;email&quot; type=&quot;radio&quot;&gt;&lt;label for=&quot;message_contactmethod_email&quot;&gt;Email&lt;/label&gt;
    &lt;input id=&quot;message_contactmethod_sms&quot; name=&quot;message[contactmethod]&quot; value=&quot;sms&quot; type=&quot;radio&quot;&gt; &lt;label for=&quot;message_contactmethod_sms&quot;&gt;SMS&lt;/label&gt;

Labels for radio buttons in rails form

I would like to write a Ruby on Rails application that consumes a RESTful web service API performs some logic on the result and then displays that data on my view.  For example, let&#39;s say I wanted to write a program that did a search on search.twitter.com.  Using pure ruby I might create the following method:

    def run(search_term=&#39;&#39;, last_id=0)
      @results = []
      url = URI.parse(&quot;http://search.twitter.com&quot;)
      res = Net::HTTP.start(url.host, url.port) do |http|
        http.get(&quot;/search.json?q=#{search_term}&amp;since_id=#{last_id.to_s}&quot;)
      end
      @results = JSON.parse res.body
    end

I&#39;m tempted to just drop that method into my Rails controller as a private method, but part of me thinks that there is a better, more &quot;Rails&quot; way to do this.  Is there a best practice approach or is this really the best way?

What is the proper &quot;Rails Way&quot; to consume a RESTful web service on another domain?

What&#39;s the best way to require all files from a directory in ruby ?

Best way to require all files from a directory in ruby?

When I see any Ruby method printed in text, it usually appears as:

    Class#method

or

    #method

Now, I would use:

    Class.method

Why are all Ruby methods preceded by a pound sign? Is there any reason for it?

Why are methods in Ruby documentation preceded by a hash sign?

I am trying to get the difference in hours for two different Time instances. I get these values from the DB as a :datetime column 

How can I do this so that it includes the months and years as well in the calculation while ignoring or rounding the minutes? Can this only be done manually or is there a function to do this?

Time difference in hours

Ok, suppose I have Ruby program to read version control log files and do something with the data. (I don&#39;t, but the situation is analogous, and I have fun with these analogies). Let&#39;s suppose right now I want to support Bazaar and Git. Let&#39;s suppose the program will be executed with some kind of argument indicating which version control software is being used.

Given this, I want to make a LogFileReaderFactory which given the name of a version control program will return an appropriate log file reader (subclassed from a generic) to read the log file and spit out a canonical internal representation. So, of course, I can make BazaarLogFileReader and GitLogFileReader and hard-code them into the program, but I want it to be set up in such a way that adding support for a new version control program is as simple as plopping a new class file in the directory with the Bazaar and Git readers.

So, right now you can call &quot;do-something-with-the-log --software git&quot; and &quot;do-something-with-the-log --software bazaar&quot; because there are log readers for those. What I want is for it to be possible to simply add a SVNLogFileReader class and file to the same directory and automatically be able to call &quot;do-something-with-the-log --software svn&quot; without ANY changes to the rest of the program. (The files can of course be named with a specific pattern and globbed in the require call.)

I know this can be done in Ruby... I just don&#39;t how I should do it... or if I should do it at all.

Ruby design pattern: How to make an extensible factory class?

I have a rake task that needs to insert a value into multiple databases.  

I&#39;d like to pass this value into the rake task from the command line, or from *another* rake task.

How can I do this?

How to pass command line arguments to a rake task

I know you can view all possible rake tasks by typing

    rake -T

But I need to know what exactly a task does.  From the output, how can I find a source file that actually has the task?  For example, I&#39;m trying to find the source for the db:schema:dump task.

How do I find the source file for a rake task?

I am trying to create a custom rake task, but it seems I dont have access to my models. I thought this was something implicitly included with rails task.

I have the following code in lib/tasks/test.rake:

    namespace :test do
      task :new_task do
        puts Parent.all.inspect
      end
    end


And here is what my parent model looks like:

    class Parent &lt; ActiveRecord::Base
      has_many :children
    end


It&#39;s a pretty simple example, but I get the following error:

    /&gt; rake test:new_task
    (in /Users/arash/Documents/dev/soft_deletes)
    rake aborted!
    uninitialized constant Parent
    
    (See full trace by running task with --trace)


Any ideas? Thanks


Do rails rake tasks provide access to ActiveRecord models?

I&#39;d like to run a rake task in my controller. Is there any way to do this?

Run rake task in controller

I&#39;m trying to run just one migration out of a whole bunch in my rails app.  How can I do this? I don&#39;t want to run any of the migrations before or after it. Thanks.

Content Type	Original Author	Original Content on Stackoverflow
Question	Skip	View Question on Stackoverflow
Solution 1 - Ruby on-Rails	bryanbraun	View Answer on Stackoverflow
Solution 2 - Ruby on-Rails	David M	View Answer on Stackoverflow
Solution 3 - Ruby on-Rails	Jörg W Mittag	View Answer on Stackoverflow
Solution 4 - Ruby on-Rails	August Lilleaas	View Answer on Stackoverflow

What exactly is Rake?

Ruby on-Rails Problem Overview

Ruby on-Rails Solutions

Solution 1 - Ruby on-Rails

Solution 2 - Ruby on-Rails

Solution 3 - Ruby on-Rails

Solution 4 - Ruby on-Rails

How to Compile for OS X in Linux or Windows?

Creating multiple log files of different content with log4j

Attributions