Merge pull request #9 from ka8725/schema-squasher

Schema squasher

.gitignore

@@ -15,3 +15,4 @@ spec/reports
 test/tmp
 test/version_tmp
 tmp
+test/rails_app/db/migrate

README.md

@@ -79,8 +79,11 @@ describe CreateUsers do
 end
 ```
 
-The helper to load migrations `require_migration` is defined in the `migration_data/testing`. So you should to require it
-to have access to this convinient require extension.
+The helper to load migrations `require_migration` is defined in the `migration_data/testing`. So you should to require it to have access to this convinient require extension.
+
+## Clean old migration
+
+Once you are tired maintaining your old migrations you can clean up the old migrations. Use `rake db:migrate:squash` for this. The task will remove all old your migrations and will generate one migration with current database schema. You don't have to run migrations after this because the generated migration will have the latest database version.
 
 ## Contributing
 

lib/migration_data.rb

@@ -2,4 +2,7 @@
 require 'migration_data/version'
 require 'migration_data/active_record/migration'
 
+require 'rake'
+import File.join(File.dirname(__FILE__), 'tasks', 'db.rake')
+
 ActiveRecord::Migration.send(:include, MigrationData::ActiveRecord::Migration)

lib/migration_data/active_record/schema_dumper.rb

@@ -0,0 +1,16 @@
+module MigrationData
+  module ActiveRecord
+    class SchemaDumper < ::ActiveRecord::SchemaDumper
+      def self.dump(connection=::ActiveRecord::Base.connection, stream=StringIO.new, config = ::ActiveRecord::Base)
+        new(connection, generate_options(config)).dump(stream)
+        stream
+      end
+
+      def dump(stream)
+        extensions(stream)
+        tables(stream)
+        stream
+      end
+    end
+  end
+end

lib/migration_data/squash.rb

@@ -0,0 +1,49 @@
+require 'migration_data/active_record/schema_dumper'
+
+module MigrationData
+  class Squash
+    def call
+      remove_all_old_migrations
+      squash_schema
+    end
+
+    private
+
+    def squash_schema
+      File.open(migration_file_name, 'w') do |f|
+        content =
+        <<-MIGRATION.gsub(/^ {10}/, '')
+          class CreateSchema < ActiveRecord::Migration
+            def change
+            #{MigrationData::ActiveRecord::SchemaDumper.dump.string.strip.gsub(/^/, '  ')}
+            end
+          end
+        MIGRATION
+
+        f.write(content)
+      end
+    end
+
+    def remove_all_old_migrations
+      migration_dirs.each do |dir|
+        FileUtils.rm_rf(Dir.glob(File.join(dir, '**/*.rb')))
+      end
+    end
+
+    def current_version
+      ::ActiveRecord::Migrator.current_version
+    end
+
+    def migration_dirs
+      ::ActiveRecord::Tasks::DatabaseTasks.migrations_paths
+    end
+
+    def migration_dir
+      migration_dirs.first
+    end
+
+    def migration_file_name
+      File.join(migration_dir, "#{current_version}_create_schema.rb")
+    end
+  end
+end

lib/tasks/db.rake

@@ -0,0 +1,10 @@
+require 'migration_data/squash'
+
+namespace :db do
+  namespace :migrate do
+    desc 'Squashes all current migrations and dumps current schema to the latest one'
+    task :squash do
+      MigrationData::Squash.new.call
+    end
+  end
+end

test/rake_task_test.rb

@@ -0,0 +1,30 @@
+require 'test_helper'
+require 'migration_data/squash'
+
+describe 'db:schema:squash' do
+  let(:rake) { Rake::Application.new }
+
+  before do
+    CreateTableMigration.new.migrate(:up)
+    Rake.application = rake
+    Rake.application.rake_require('db', [File.expand_path('../../lib/tasks', __FILE__)])
+  end
+
+  describe '#invoke' do
+    it 'squashes the schema to the current migration' do
+      latest_migration = Rails.root.join('db', 'migrate', '0_create_schema.rb')
+      FileUtils.rm(latest_migration) if File.exist?(latest_migration)
+
+      Rake::Task['db:migrate:squash'].invoke
+      assert_equal <<-MIGRATION, File.read(latest_migration)
+class CreateSchema < ActiveRecord::Migration
+  def change
+    create_table \"users\", force: :cascade do |t|
+      t.string \"name\"
+    end
+  end
+end
+      MIGRATION
+    end
+  end
+end

test/schema_dumper_test.rb

@@ -0,0 +1,20 @@
+require 'test_helper'
+require 'migration_data/active_record/schema_dumper'
+
+describe MigrationData::ActiveRecord::SchemaDumper do
+  before do
+    CreateTableMigration.new.migrate(:up)
+  end
+
+  describe '#dump' do
+    it 'squashes the schema' do
+      stream = MigrationData::ActiveRecord::SchemaDumper.dump
+      assert_equal <<-SCHEMA, stream.string
+  create_table \"users\", force: :cascade do |t|
+    t.string \"name\"
+  end
+
+      SCHEMA
+    end
+  end
+end

test/squash_test.rb

@@ -0,0 +1,39 @@
+require 'test_helper'
+require 'migration_data/squash'
+
+describe MigrationData::Squash do
+  let(:squash) { MigrationData::Squash.new }
+  let(:db_path) { Rails.root.join('db', 'migrate') }
+
+  before do
+    CreateTableMigration.new.migrate(:up)
+  end
+
+  describe '#call' do
+    it 'squashes the schema to the current migration' do
+      squash.stub(:current_version, '100500') do
+        squash.call
+      end
+      assert_equal <<-MIGRATION, File.read(db_path.join('100500_create_schema.rb'))
+class CreateSchema < ActiveRecord::Migration
+  def change
+    create_table \"users\", force: :cascade do |t|
+      t.string \"name\"
+    end
+  end
+end
+      MIGRATION
+    end
+
+    it 'removes all the old migrations' do
+      old_migration = db_path.join('100500_old_migration.rb')
+      File.write(old_migration, '')
+
+      assert_equal true, File.exist?(old_migration)
+
+      squash.call
+
+      assert_equal false, File.exist?(old_migration)
+    end
+  end
+end

test/support/create_table_migration.rb

@@ -0,0 +1,7 @@
+class CreateTableMigration < ActiveRecord::Migration
+  def change
+    create_table :users, force: true do |t|
+      t.string :name
+    end
+  end
+end

test/support/rails_app.rb

@@ -0,0 +1,6 @@
+class RailsApp < Rails::Application
+end
+
+Rails.application.config.root = 'test/rails_app'
+
+FileUtils.mkdir_p(Rails.application.config.root.join('db', 'migrate'))

test/test_helper.rb

@@ -1,4 +1,7 @@
 require 'minitest/autorun'
 require 'migration_data'
+require 'rails'
 
-ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: 'tmp/test.sqlite3')
+Dir[File.join(File.dirname(__FILE__), 'support', '**/*.rb')].each { |f| require f }
+
+ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: 'tmp/test.sqlite3')