dbtasks.rb

  desc "migrate", "Runs Sequel migrations"
  def migrate(version=nil, database_url=DATABASE_URL)
    require 'sequel'
    Sequel.extension :migration
    db = Sequel.connect(database_url, :test => true)

    puts 'Running migrations...'
    Sequel::Migrator.apply(db, 'db/migrate', version && version.to_i)

    dump_schema
  end

  desc "create_migration", "Creates a Sequel migration"
  def create_migration(name, version=nil)
    migrations_dir = File.join("db", "migrate")
    version ||= Time.now.utc.strftime("%Y%m%d%H%M%S")
    filename = "#{version}_#{name}.rb"

    FileUtils.mkdir_p(migrations_dir)

    open(File.join(migrations_dir, filename), 'w') do |f|
      f << (<<-EOS).gsub("      ", "")
      Sequel.migration do
        change do
        end
      end
      EOS
    end
  end

  desc "dump_schema", "Generates db/schema.rb"
  def dump_schema(database_url=DATABASE_URL,
                  schema_file="#{File.dirname(__FILE__)}/db/schema.rb")
    require 'sequel'
    Sequel.extension :schema_dumper
    db = Sequel.connect(database_url, :test => true)

    puts 'Dumping schema...'
    open(schema_file, 'w') do |f|
      f << db.dump_schema_migration(:same_db => false)
    end
  end

  desc "dump_schema_image", "Generates doc/schema.png"
  def dump_schema_image
    require './init'

    associations = []
    classes = []
    File.open('doc/schema.dot', 'w') do |out|
      Sequel::Model.descendents.each do |c|
        next if c.name.blank?
        c.associations.each do |a|
          ar = c.association_reflection(a)
          begin
            ac = ar.associated_class
          rescue NameError
            $stderr.puts "Couldn't get associated class for #{c}.#{ar[:type]} #{ar[:name].inspect}"
          else
            associations << [c.name, ar[:type], ac.name]
          end
        end
      end
      styles = {:many_to_one=>:bold, :one_to_many=>:solid, :many_to_many=>:dashed, :one_to_one=>:dotted}
      out << "digraph G {\n"
      out << associations.uniq.map{|c, t, ac| "  #{c} -> #{ac} [style=#{styles[t]}];"}.sort.join("\n")
      out << "\n}\n"
    end

    system('dot -Tpng doc/schema.dot > doc/schema.png')

    puts 'Done.'
  end