Database config in Ruby

Really attach the patch this time.

I like this!

I'm adding a patch based off Adam's one that would allow you to do something like this (I use defaults in YAML so this is needed for a Ruby version for me):

Rails::DatabaseSpecGenerator.map do |db|
  db.defaults :config => {
    :adapter => 'mysql',
    :encoding => 'utf8'
  }

  db.development :config => {
    :database => 'ryokan_development'
  }.merge(db.defaults)
end

The syntax is not DSL-ish nor perfect but at least it's understandable ruby.

Also some minor tweaks like removing the @@@returning@@@ block and using File.extname to check for file extensions.

I'm curious what advantages db.defaults has something like this:

Rails::DatabaseSpecGenerator.map do |db|
  defaults = {:adapter => 'mysql', :encoding => 'utf8'}

  db.development :config => defaults.merge(:database => 'ryokan_development'}
end

That said, I'm working on a somewhat different approach to this. Will post it here once I'm done.

Just attached a reworked version. This time 'round, the database config hangs off of ActiveRecord itself. You can set it in your generic environment or a specific environment file. For example, in `config/environment.rb` :

  config.active_record.configure do |db|
    db.development do |setup|
      socket = %w{/tmp/mysql.sock /var/run/mysql.sock}.detect do |f|
        File.exists?(f)
      end
      setup.database = "test_app_#{Rails.env}"
      setup.adapter  = 'mysql'
      setup.socket = socket
      setup.credentials = "#{RAILS_ROOT}/config/credentials.rb"
    end
    
    db.production do |setup|
      socket = %w{/tmp/mysql.sock /var/run/mysql.sock}.detect do |f|
        File.exists?(f)
      end
      setup.database = "test_app_#{Rails.env}"
      setup.adapter  = 'mysql'
      setup.socket = socket
      # setup.credentials = "#{RAILS_ROOT}/config/credentials.rb"
    end
  end

Or, in `config/environments/development.rb` :

config.active_record.configure do |db|
  db.development do |setup|
    setup.database = 'test_app_development'
  end
end

Note you can set `credentials`. This loads a YAML or Ruby file with the database username/password information:

username: root
password: 

username = 'root'
password = ''

You must use a credentials file in production, otherwise an exception is raised.

If this version looks good, I'll start on app generator changes.

Hey, that's pretty nice.

What's the advantage of a DSL here (config builder) over, say, assigning a hash? e.g.

  config.active_record.databases = {
    :development => {
      :adapter => 'mysql',
      :socket => find_socket,
      :database => "#{test_app_#{Rails.env}",
      :credentials => "#{Rails.root}/config/credentials.rb"
    }, ...

The blocks let you delay execution, but I'm not sure that's needed.

yeah, pretend I wrote some valid Ruby too ^^^

Jeremy: well in this case, having real methods makes it cleaner, IMHO, to do things like yell at the developer if they set a username/password in production mode. But really, I like the look of the block version better than a hash-y version.

As an aside, I would love to not delay execution, but AR isn't loaded when environments are evaluated.

I went ahead and did the generators. Here's what it looks like for a fresh app generated for MySQL:

  # Specify your database connections. You can partially configure your
  # your database here and then finish in an environment-specific file or
  # an initializer.
  config.active_record.configure do |db|
    
    # MySQL.  Versions 4.1 and 5.0 are recommended.
    #
    # Install the MySQL driver:
    #   gem install mysql
    # On Mac OS X:
    #   sudo gem install mysql -- --with-mysql-dir=/usr/local/mysql
    # On Mac OS X Leopard:
    #   sudo env ARCHFLAGS="-arch i386" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
    #       This sets the ARCHFLAGS environment variable to your native architecture
    # On Windows:
    #   gem install mysql
    #       Choose the win32 build.
    #       Install MySQL and put its /bin directory on your path.
    #
    # And be sure to use new-style password hashing:
    #   http://dev.mysql.com/doc/refman/...
    db.development do |setup|
      setup.encoding = utf8
      setup.username = root
      setup.password = 
      setup.socket = /tmp/mysql.sock
      setup.adapter = mysql
      setup.database = foo_development
    end
    
    # Warning: The database defined as "test" will be erased and
    # re-generated from your development database when you run "rake".
    # Do not set this db to the same as development or production.
    db.test do |setup|
      setup.encoding = utf8
      setup.username = root
      setup.password = 
      setup.socket = /tmp/mysql.sock
      setup.adapter = mysql
      setup.database = foo_test
    end
    
    # You cannot specify the username and password for your database directly
    # here. You need to add those details to a credentials file that looks
    # like this:
    #
    #  username = 'root'
    #  password = ''
    #
    # Specify the path to your credentials file below. For more info see 
    # http://rubyonrails.org/awesome_c...
    db.production do |setup|
      setup.encoding = utf8
      setup.credentials = "/path/to/your/credentials.rb"
      setup.socket = /tmp/mysql.sock
      setup.adapter = mysql
      setup.database = foo_production
    end
  end

Looking for feedback on the code and/or copy.

Updated patch to allow DRYer AR configuration. In environment.rb :

config.active_record.configure do |db|
    
    db.encoding = utf8
    db.adapter = 'mysql'
    db.socket = /tmp/mysql.sock
    db.database = 'foo_development'
    
  end

@development.rb@:

config.active_record.connection.configure do |db|
  db.username = 'root'
  db.password = ''
  db.database = 'foo_development'
end

@production.rb@:

config.active_record.connection.configure do |db|
  db.database = 'foo_production'
  db.credentials = '/path/to/your/credentials.rb'
end

environments.rb is loaded first. Environment-specific files overwrite anything set previously.

I have to say that the credentials in a file means that rather than saving another file from getting checked in, what you are doing is just drying up database.yml - which is fine if it's an itch you want scratching :)

to be honest- it might be more interesting drying it up properly. Why not get opinionated and append _dev/_prod/_test to the name of your db- so in env, set db.name = "foo" and the name of each db is inferred, unless you override and explicitly set in each env?

@James yeah its completely possible to define the whole thing in environment.rb like so:

  config.active_record.connection.configure do |db|
    db.adapter  = 'mysql'
    db.encoding = 'utf8'
    db.database = "test_app_#{Rails.env}"
    db.socket = %w{/tmp/mysql.sock /var/run/mysql.sock}.detect do |f|
      File.exists?(f)
    end
    db.credentials = "#{RAILS_ROOT}/config/credentials.rb"
  end

You can then override anything you want (adapter, credentials, etc.) in environment-specific files.

I think this is a great direction, but I just wanted to note that using a hash might be more consistent with how email configuration works (e.g. config.action_mailer.smtp_settings)

Trevor: indeed, I considered using a Hash. However, using a proper object makes it easier to yell at those who would explicitly set a username/password for their production database. ;)

-1

See comments on mailing list thread (which contains another -1 from another poster) for explanation.

-1

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It might make for a nice plugin for those who desire such a feature.