michaeldwan · October 14, 2011 18:30 · Oct 14, 2011 · Oct 14, 2011 · Oct 14, 2011
diff --git a/...tors.mongo_migrationtemplatesmigration.rb → ...rs.mongo_migration.templates.migration.rb b/...tors.mongo_migrationtemplatesmigration.rb → ...rs.mongo_migration.templates.migration.rb
diff --git a/generators.mongo_migration.mongo_migration_generator.rb b/generators.mongo_migration.mongo_migration_generator.rb
@@ -0,0 +1,8 @@
+class MongoMigrationGenerator < Rails::Generators::NamedBase
+  source_root File.expand_path('../templates', __FILE__)
+
+  def create_mongo_migration_file
+    version = Time.now.utc.strftime("%Y%m%d%H%M%S")
+    template "migration.rb", "db/mongo_migrations/#{version}_#{file_name}.rb"
+  end
+end
diff --git a/generators.mongo_migrationtemplatesmigration.rb b/generators.mongo_migrationtemplatesmigration.rb
@@ -0,0 +1,7 @@
+class <%= file_name.camelize %> < ::Mongo::Migration
+  def self.up
+  end
+
+  def self.down
+  end
+end
diff --git a/migration.rb b/migration.rb
@@ -0,0 +1,7 @@
+module Mongo
+  class Migration
+    def self.say(message, subitem = false)
+      puts "#{subitem ? "   ->" : "--"} #{message}"
+    end
+  end
+end
diff --git a/migrator.rb b/migrator.rb
@@ -0,0 +1,128 @@
+module Mongo
+  class Migrator
+    def self.database=(db)
+      raise "wtf is this? we need a Mongo::DB" unless db.is_a?(Mongo::DB)
+      @database = db
+    end
+
+    def self.database
+      unless @database
+        self.database = MongoMapper.database if defined?(MongoMapper)
+      end
+      return @database
+    end
+
+    def self.collection_name
+      @collection_name ||= "migrations"
+    end
+
+    def self.collection_name=(value)
+      @collection_name = value
+    end
+
+    def self.migrations_path
+      @migrations_path ||= Rails.root.join('db', 'mongo_migrations')
+    end
+
+    def self.migrations_path=(value)
+      @migrations_path = value
+    end
+
+    def self.version_history
+      database[collection_name].distinct('version')
+    end
+
+    def self.save_history(direction, version)
+      case direction
+      when :up then database[collection_name].save(:version => version)
+      when :down then database[collection_name].remove(:version => version)
+      end
+    end
+
+    def self.available_migrations
+      @migrations ||= begin
+        Dir["#{migrations_path}/*.rb"].map do |migration_file|
+          MigrationProxy.new(*[File.basename(migration_file).scan(/([0-9]+)_([_a-z0-9]*).rb/).first, migration_file].flatten)
+        end.sort_by(&:version)
+      end
+    end
+
+    def self.pending_migrations
+      history = version_history
+      available_migrations.reject { |m| history.include?(m.version) }
+    end
+
+    def self.processed_migrations
+      history = version_history
+      available_migrations.select { |m| history.include?(m.version) }
+    end
+
+    def self.current_version
+      version_history.max
+    end
+
+    def initialize(options = {})
+      @version = options[:version]
+      @direction = options[:direction] || :up
+    end
+
+    attr_reader :version, :direction
+
+    def queue
+      @queue ||= begin
+        if version
+          if direction == :up
+            [self.class.pending_migrations.detect { |m| m.version == version }]
+          elsif direction == :down
+            [self.class.processed_migrations.detect { |m| m.version == version }]
+          end
+        elsif direction == :up
+          self.class.pending_migrations
+        else
+          []
+        end
+      end
+    end
+
+    def run!
+      queue.each do |migration|
+        migration.run(direction)
+        self.class.save_history(direction, migration.version)
+      end
+    end
+
+    class MigrationProxy < Struct.new(:version, :name, :file)
+      def migration
+        @instance ||= begin
+          load(file)
+          name.camelize.constantize
+        end
+      end
+
+      def run(direction = :up)
+        return unless migration.respond_to?(direction)
+
+        case direction
+          when :up   then announce "migrating"
+          when :down then announce "reverting"
+        end
+
+        result = nil
+        time = Benchmark.measure { result = migration.send("#{direction}") }
+
+        case direction
+          when :up   then announce "migrated (%.4fs)" % time.real; puts
+          when :down then announce "reverted (%.4fs)" % time.real; puts
+        end
+
+        result
+      end
+
+      def announce(message)
+        text = "#{version} #{name}: #{message}"
+        length = [0, 75 - text.length].max
+        puts "== %s %s" % [text, "=" * length]
+      end
+    end
+  end
+end