require "set" require "zlib" require "active_support/core_ext/module/attribute_accessors" module ActiveRecord class MigrationError < ActiveRecordError#:nodoc: def initialize(message = nil) message = "\n\n#{message}\n\n" if message super end end # Exception that can be raised to stop migrations from being rolled back. # For example the following migration is not reversible. # Rolling back this migration will raise an ActiveRecord::IrreversibleMigration error. # # class IrreversibleMigrationExample < ActiveRecord::Migration[5.0] # def change # create_table :distributors do |t| # t.string :zipcode # end # # execute <<-SQL # ALTER TABLE distributors # ADD CONSTRAINT zipchk # CHECK (char_length(zipcode) = 5) NO INHERIT; # SQL # end # end # # There are two ways to mitigate this problem. # # 1. Define #up and #down methods instead of #change: # # class ReversibleMigrationExample < ActiveRecord::Migration[5.0] # def up # create_table :distributors do |t| # t.string :zipcode # end # # execute <<-SQL # ALTER TABLE distributors # ADD CONSTRAINT zipchk # CHECK (char_length(zipcode) = 5) NO INHERIT; # SQL # end # # def down # execute <<-SQL # ALTER TABLE distributors # DROP CONSTRAINT zipchk # SQL # # drop_table :distributors # end # end # # 2. Use the #reversible method in #change method: # # class ReversibleMigrationExample < ActiveRecord::Migration[5.0] # def change # create_table :distributors do |t| # t.string :zipcode # end # # reversible do |dir| # dir.up do # execute <<-SQL # ALTER TABLE distributors # ADD CONSTRAINT zipchk # CHECK (char_length(zipcode) = 5) NO INHERIT; # SQL # end # # dir.down do # execute <<-SQL # ALTER TABLE distributors # DROP CONSTRAINT zipchk # SQL # end # end # end # end class IrreversibleMigration < MigrationError end class DuplicateMigrationVersionError < MigrationError#:nodoc: def initialize(version = nil) if version super("Multiple migrations have the version number #{version}.") else super("Duplicate migration version error.") end end end class DuplicateMigrationNameError < MigrationError#:nodoc: def initialize(name = nil) if name super("Multiple migrations have the name #{name}.") else super("Duplicate migration name.") end end end class UnknownMigrationVersionError < MigrationError #:nodoc: def initialize(version = nil) if version super("No migration with version number #{version}.") else super("Unknown migration version.") end end end class IllegalMigrationNameError < MigrationError#:nodoc: def initialize(name = nil) if name super("Illegal name for migration file: #{name}\n\t(only lower case letters, numbers, and '_' allowed).") else super("Illegal name for migration.") end end end class PendingMigrationError < MigrationError#:nodoc: def initialize(message = nil) if !message && defined?(Rails.env) super("Migrations are pending. To resolve this issue, run:\n\n bin/rails db:migrate RAILS_ENV=#{::Rails.env}") elsif !message super("Migrations are pending. To resolve this issue, run:\n\n bin/rails db:migrate") else super end end end class ConcurrentMigrationError < MigrationError #:nodoc: DEFAULT_MESSAGE = "Cannot run migrations because another migration process is currently running.".freeze def initialize(message = DEFAULT_MESSAGE) super end end class NoEnvironmentInSchemaError < MigrationError #:nodoc: def initialize msg = "Environment data not found in the schema. To resolve this issue, run: \n\n bin/rails db:environment:set" if defined?(Rails.env) super("#{msg} RAILS_ENV=#{::Rails.env}") else super(msg) end end end class ProtectedEnvironmentError < ActiveRecordError #:nodoc: def initialize(env = "production") msg = "You are attempting to run a destructive action against your '#{env}' database.\n" msg << "If you are sure you want to continue, run the same command with the environment variable:\n" msg << "DISABLE_DATABASE_ENVIRONMENT_CHECK=1" super(msg) end end class EnvironmentMismatchError < ActiveRecordError def initialize(current: nil, stored: nil) msg = "You are attempting to modify a database that was last run in `#{ stored }` environment.\n" msg << "You are running in `#{ current }` environment. " msg << "If you are sure you want to continue, first set the environment using:\n\n" msg << " bin/rails db:environment:set" if defined?(Rails.env) super("#{msg} RAILS_ENV=#{::Rails.env}\n\n") else super("#{msg}\n\n") end end end # = Active Record Migrations # # Migrations can manage the evolution of a schema used by several physical # databases. It's a solution to the common problem of adding a field to make # a new feature work in your local database, but being unsure of how to # push that change to other developers and to the production server. With # migrations, you can describe the transformations in self-contained classes # that can be checked into version control systems and executed against # another database that might be one, two, or five versions behind. # # Example of a simple migration: # # class AddSsl < ActiveRecord::Migration[5.0] # def up # add_column :accounts, :ssl_enabled, :boolean, default: true # end # # def down # remove_column :accounts, :ssl_enabled # end # end # # This migration will add a boolean flag to the accounts table and remove it # if you're backing out of the migration. It shows how all migrations have # two methods +up+ and +down+ that describes the transformations # required to implement or remove the migration. These methods can consist # of both the migration specific methods like +add_column+ and +remove_column+, # but may also contain regular Ruby code for generating data needed for the # transformations. # # Example of a more complex migration that also needs to initialize data: # # class AddSystemSettings < ActiveRecord::Migration[5.0] # def up # create_table :system_settings do |t| # t.string :name # t.string :label # t.text :value # t.string :type # t.integer :position # end # # SystemSetting.create name: 'notice', # label: 'Use notice?', # value: 1 # end # # def down # drop_table :system_settings # end # end # # This migration first adds the +system_settings+ table, then creates the very # first row in it using the Active Record model that relies on the table. It # also uses the more advanced +create_table+ syntax where you can specify a # complete table schema in one block call. # # == Available transformations # # === Creation # # * create_join_table(table_1, table_2, options): Creates a join # table having its name as the lexical order of the first two # arguments. See # ActiveRecord::ConnectionAdapters::SchemaStatements#create_join_table for # details. # * create_table(name, options): Creates a table called +name+ and # makes the table object available to a block that can then add columns to it, # following the same format as +add_column+. See example above. The options hash # is for fragments like "DEFAULT CHARSET=UTF-8" that are appended to the create # table definition. # * add_column(table_name, column_name, type, options): Adds a new column # to the table called +table_name+ # named +column_name+ specified to be one of the following types: # :string, :text, :integer, :float, # :decimal, :datetime, :timestamp, :time, # :date, :binary, :boolean. A default value can be # specified by passing an +options+ hash like { default: 11 }. # Other options include :limit and :null (e.g. # { limit: 50, null: false }) -- see # ActiveRecord::ConnectionAdapters::TableDefinition#column for details. # * add_foreign_key(from_table, to_table, options): Adds a new # foreign key. +from_table+ is the table with the key column, +to_table+ contains # the referenced primary key. # * add_index(table_name, column_names, options): Adds a new index # with the name of the column. Other options include # :name, :unique (e.g. # { name: 'users_name_index', unique: true }) and :order # (e.g. { order: { name: :desc } }). # * add_reference(:table_name, :reference_name): Adds a new column # +reference_name_id+ by default an integer. See # ActiveRecord::ConnectionAdapters::SchemaStatements#add_reference for details. # * add_timestamps(table_name, options): Adds timestamps (+created_at+ # and +updated_at+) columns to +table_name+. # # === Modification # # * change_column(table_name, column_name, type, options): Changes # the column to a different type using the same parameters as add_column. # * change_column_default(table_name, column_name, default_or_changes): # Sets a default value for +column_name+ defined by +default_or_changes+ on # +table_name+. Passing a hash containing :from and :to # as +default_or_changes+ will make this change reversible in the migration. # * change_column_null(table_name, column_name, null, default = nil): # Sets or removes a +NOT NULL+ constraint on +column_name+. The +null+ flag # indicates whether the value can be +NULL+. See # ActiveRecord::ConnectionAdapters::SchemaStatements#change_column_null for # details. # * change_table(name, options): Allows to make column alterations to # the table called +name+. It makes the table object available to a block that # can then add/remove columns, indexes or foreign keys to it. # * rename_column(table_name, column_name, new_column_name): Renames # a column but keeps the type and content. # * rename_index(table_name, old_name, new_name): Renames an index. # * rename_table(old_name, new_name): Renames the table called +old_name+ # to +new_name+. # # === Deletion # # * drop_table(name): Drops the table called +name+. # * drop_join_table(table_1, table_2, options): Drops the join table # specified by the given arguments. # * remove_column(table_name, column_name, type, options): Removes the column # named +column_name+ from the table called +table_name+. # * remove_columns(table_name, *column_names): Removes the given # columns from the table definition. # * remove_foreign_key(from_table, options_or_to_table): Removes the # given foreign key from the table called +table_name+. # * remove_index(table_name, column: column_names): Removes the index # specified by +column_names+. # * remove_index(table_name, name: index_name): Removes the index # specified by +index_name+. # * remove_reference(table_name, ref_name, options): Removes the # reference(s) on +table_name+ specified by +ref_name+. # * remove_timestamps(table_name, options): Removes the timestamp # columns (+created_at+ and +updated_at+) from the table definition. # # == Irreversible transformations # # Some transformations are destructive in a manner that cannot be reversed. # Migrations of that kind should raise an ActiveRecord::IrreversibleMigration # exception in their +down+ method. # # == Running migrations from within Rails # # The Rails package has several tools to help create and apply migrations. # # To generate a new migration, you can use # rails generate migration MyNewMigration # # where MyNewMigration is the name of your migration. The generator will # create an empty migration file timestamp_my_new_migration.rb # in the db/migrate/ directory where timestamp is the # UTC formatted date and time that the migration was generated. # # There is a special syntactic shortcut to generate migrations that add fields to a table. # # rails generate migration add_fieldname_to_tablename fieldname:string # # This will generate the file timestamp_add_fieldname_to_tablename.rb, which will look like this: # class AddFieldnameToTablename < ActiveRecord::Migration[5.0] # def change # add_column :tablenames, :fieldname, :string # end # end # # To run migrations against the currently configured database, use # rails db:migrate. This will update the database by running all of the # pending migrations, creating the schema_migrations table # (see "About the schema_migrations table" section below) if missing. It will also # invoke the db:schema:dump task, which will update your db/schema.rb file # to match the structure of your database. # # To roll the database back to a previous migration version, use # rails db:migrate VERSION=X where X is the version to which # you wish to downgrade. Alternatively, you can also use the STEP option if you # wish to rollback last few migrations. rails db:migrate STEP=2 will rollback # the latest two migrations. # # If any of the migrations throw an ActiveRecord::IrreversibleMigration exception, # that step will fail and you'll have some manual work to do. # # == Database support # # Migrations are currently supported in MySQL, PostgreSQL, SQLite, # SQL Server, and Oracle (all supported databases except DB2). # # == More examples # # Not all migrations change the schema. Some just fix the data: # # class RemoveEmptyTags < ActiveRecord::Migration[5.0] # def up # Tag.all.each { |tag| tag.destroy if tag.pages.empty? } # end # # def down # # not much we can do to restore deleted data # raise ActiveRecord::IrreversibleMigration, "Can't recover the deleted tags" # end # end # # Others remove columns when they migrate up instead of down: # # class RemoveUnnecessaryItemAttributes < ActiveRecord::Migration[5.0] # def up # remove_column :items, :incomplete_items_count # remove_column :items, :completed_items_count # end # # def down # add_column :items, :incomplete_items_count # add_column :items, :completed_items_count # end # end # # And sometimes you need to do something in SQL not abstracted directly by migrations: # # class MakeJoinUnique < ActiveRecord::Migration[5.0] # def up # execute "ALTER TABLE `pages_linked_pages` ADD UNIQUE `page_id_linked_page_id` (`page_id`,`linked_page_id`)" # end # # def down # execute "ALTER TABLE `pages_linked_pages` DROP INDEX `page_id_linked_page_id`" # end # end # # == Using a model after changing its table # # Sometimes you'll want to add a column in a migration and populate it # immediately after. In that case, you'll need to make a call to # Base#reset_column_information in order to ensure that the model has the # latest column data from after the new column was added. Example: # # class AddPeopleSalary < ActiveRecord::Migration[5.0] # def up # add_column :people, :salary, :integer # Person.reset_column_information # Person.all.each do |p| # p.update_attribute :salary, SalaryCalculator.compute(p) # end # end # end # # == Controlling verbosity # # By default, migrations will describe the actions they are taking, writing # them to the console as they happen, along with benchmarks describing how # long each step took. # # You can quiet them down by setting ActiveRecord::Migration.verbose = false. # # You can also insert your own messages and benchmarks by using the +say_with_time+ # method: # # def up # ... # say_with_time "Updating salaries..." do # Person.all.each do |p| # p.update_attribute :salary, SalaryCalculator.compute(p) # end # end # ... # end # # The phrase "Updating salaries..." would then be printed, along with the # benchmark for the block when the block completes. # # == Timestamped Migrations # # By default, Rails generates migrations that look like: # # 20080717013526_your_migration_name.rb # # The prefix is a generation timestamp (in UTC). # # If you'd prefer to use numeric prefixes, you can turn timestamped migrations # off by setting: # # config.active_record.timestamped_migrations = false # # In application.rb. # # == Reversible Migrations # # Reversible migrations are migrations that know how to go +down+ for you. # You simply supply the +up+ logic, and the Migration system figures out # how to execute the down commands for you. # # To define a reversible migration, define the +change+ method in your # migration like this: # # class TenderloveMigration < ActiveRecord::Migration[5.0] # def change # create_table(:horses) do |t| # t.column :content, :text # t.column :remind_at, :datetime # end # end # end # # This migration will create the horses table for you on the way up, and # automatically figure out how to drop the table on the way down. # # Some commands like +remove_column+ cannot be reversed. If you care to # define how to move up and down in these cases, you should define the +up+ # and +down+ methods as before. # # If a command cannot be reversed, an # ActiveRecord::IrreversibleMigration exception will be raised when # the migration is moving down. # # For a list of commands that are reversible, please see # ActiveRecord::Migration::CommandRecorder. # # == Transactional Migrations # # If the database adapter supports DDL transactions, all migrations will # automatically be wrapped in a transaction. There are queries that you # can't execute inside a transaction though, and for these situations # you can turn the automatic transactions off. # # class ChangeEnum < ActiveRecord::Migration[5.0] # disable_ddl_transaction! # # def up # execute "ALTER TYPE model_size ADD VALUE 'new_value'" # end # end # # Remember that you can still open your own transactions, even if you # are in a Migration with self.disable_ddl_transaction!. class Migration autoload :CommandRecorder, "active_record/migration/command_recorder" autoload :Compatibility, "active_record/migration/compatibility" # This must be defined before the inherited hook, below class Current < Migration # :nodoc: end def self.inherited(subclass) # :nodoc: super if subclass.superclass == Migration raise StandardError, "Directly inheriting from ActiveRecord::Migration is not supported. " \ "Please specify the Rails release the migration was written for:\n" \ "\n" \ " class #{self.class.name} < ActiveRecord::Migration[4.2]" end end def self.[](version) Compatibility.find(version) end def self.current_version ActiveRecord::VERSION::STRING.to_f end MigrationFilenameRegexp = /\A([0-9]+)_([_a-z0-9]*)\.?([_a-z0-9]*)?\.rb\z/ # :nodoc: # This class is used to verify that all migrations have been run before # loading a web page if config.active_record.migration_error is set to :page_load class CheckPending def initialize(app) @app = app @last_check = 0 end def call(env) if connection.supports_migrations? mtime = ActiveRecord::Migrator.last_migration.mtime.to_i if @last_check < mtime ActiveRecord::Migration.check_pending!(connection) @last_check = mtime end end @app.call(env) end private def connection ActiveRecord::Base.connection end end class << self attr_accessor :delegate # :nodoc: attr_accessor :disable_ddl_transaction # :nodoc: def nearest_delegate # :nodoc: delegate || superclass.nearest_delegate end # Raises ActiveRecord::PendingMigrationError error if any migrations are pending. def check_pending!(connection = Base.connection) raise ActiveRecord::PendingMigrationError if ActiveRecord::Migrator.needs_migration?(connection) end def load_schema_if_pending! if ActiveRecord::Migrator.needs_migration? || !ActiveRecord::Migrator.any_migrations? # Roundtrip to Rake to allow plugins to hook into database initialization. FileUtils.cd Rails.root do current_config = Base.connection_config Base.clear_all_connections! system("bin/rails db:test:prepare") # Establish a new connection, the old database may be gone (db:test:prepare uses purge) Base.establish_connection(current_config) end check_pending! end end def maintain_test_schema! # :nodoc: if ActiveRecord::Base.maintain_test_schema suppress_messages { load_schema_if_pending! } end end def method_missing(name, *args, &block) # :nodoc: nearest_delegate.send(name, *args, &block) end def migrate(direction) new.migrate direction end # Disable the transaction wrapping this migration. # You can still create your own transactions even after calling #disable_ddl_transaction! # # For more details read the {"Transactional Migrations" section above}[rdoc-ref:Migration]. def disable_ddl_transaction! @disable_ddl_transaction = true end end def disable_ddl_transaction # :nodoc: self.class.disable_ddl_transaction end cattr_accessor :verbose attr_accessor :name, :version def initialize(name = self.class.name, version = nil) @name = name @version = version @connection = nil end self.verbose = true # instantiate the delegate object after initialize is defined self.delegate = new # Reverses the migration commands for the given block and # the given migrations. # # The following migration will remove the table 'horses' # and create the table 'apples' on the way up, and the reverse # on the way down. # # class FixTLMigration < ActiveRecord::Migration[5.0] # def change # revert do # create_table(:horses) do |t| # t.text :content # t.datetime :remind_at # end # end # create_table(:apples) do |t| # t.string :variety # end # end # end # # Or equivalently, if +TenderloveMigration+ is defined as in the # documentation for Migration: # # require_relative '20121212123456_tenderlove_migration' # # class FixupTLMigration < ActiveRecord::Migration[5.0] # def change # revert TenderloveMigration # # create_table(:apples) do |t| # t.string :variety # end # end # end # # This command can be nested. def revert(*migration_classes) run(*migration_classes.reverse, revert: true) unless migration_classes.empty? if block_given? if connection.respond_to? :revert connection.revert { yield } else recorder = CommandRecorder.new(connection) @connection = recorder suppress_messages do connection.revert { yield } end @connection = recorder.delegate recorder.commands.each do |cmd, args, block| send(cmd, *args, &block) end end end end def reverting? connection.respond_to?(:reverting) && connection.reverting end ReversibleBlockHelper = Struct.new(:reverting) do # :nodoc: def up yield unless reverting end def down yield if reverting end end # Used to specify an operation that can be run in one direction or another. # Call the methods +up+ and +down+ of the yielded object to run a block # only in one given direction. # The whole block will be called in the right order within the migration. # # In the following example, the looping on users will always be done # when the three columns 'first_name', 'last_name' and 'full_name' exist, # even when migrating down: # # class SplitNameMigration < ActiveRecord::Migration[5.0] # def change # add_column :users, :first_name, :string # add_column :users, :last_name, :string # # reversible do |dir| # User.reset_column_information # User.all.each do |u| # dir.up { u.first_name, u.last_name = u.full_name.split(' ') } # dir.down { u.full_name = "#{u.first_name} #{u.last_name}" } # u.save # end # end # # revert { add_column :users, :full_name, :string } # end # end def reversible helper = ReversibleBlockHelper.new(reverting?) execute_block { yield helper } end # Runs the given migration classes. # Last argument can specify options: # - :direction (default is :up) # - :revert (default is false) def run(*migration_classes) opts = migration_classes.extract_options! dir = opts[:direction] || :up dir = (dir == :down ? :up : :down) if opts[:revert] if reverting? # If in revert and going :up, say, we want to execute :down without reverting, so revert { run(*migration_classes, direction: dir, revert: true) } else migration_classes.each do |migration_class| migration_class.new.exec_migration(connection, dir) end end end def up self.class.delegate = self return unless self.class.respond_to?(:up) self.class.up end def down self.class.delegate = self return unless self.class.respond_to?(:down) self.class.down end # Execute this migration in the named direction def migrate(direction) return unless respond_to?(direction) case direction when :up then announce "migrating" when :down then announce "reverting" end time = nil ActiveRecord::Base.connection_pool.with_connection do |conn| time = Benchmark.measure do exec_migration(conn, direction) end end case direction when :up then announce "migrated (%.4fs)" % time.real; write when :down then announce "reverted (%.4fs)" % time.real; write end end def exec_migration(conn, direction) @connection = conn if respond_to?(:change) if direction == :down revert { change } else change end else send(direction) end ensure @connection = nil end def write(text = "") puts(text) if verbose end def announce(message) text = "#{version} #{name}: #{message}" length = [0, 75 - text.length].max write "== %s %s" % [text, "=" * length] end def say(message, subitem = false) write "#{subitem ? " ->" : "--"} #{message}" end def say_with_time(message) say(message) result = nil time = Benchmark.measure { result = yield } say "%.4fs" % time.real, :subitem say("#{result} rows", :subitem) if result.is_a?(Integer) result end def suppress_messages save, self.verbose = verbose, false yield ensure self.verbose = save end def connection @connection || ActiveRecord::Base.connection end def method_missing(method, *arguments, &block) arg_list = arguments.map(&:inspect) * ", " say_with_time "#{method}(#{arg_list})" do unless connection.respond_to? :revert unless arguments.empty? || [:execute, :enable_extension, :disable_extension].include?(method) arguments[0] = proper_table_name(arguments.first, table_name_options) if [:rename_table, :add_foreign_key].include?(method) || (method == :remove_foreign_key && !arguments.second.is_a?(Hash)) arguments[1] = proper_table_name(arguments.second, table_name_options) end end end return super unless connection.respond_to?(method) connection.send(method, *arguments, &block) end end def copy(destination, sources, options = {}) copied = [] FileUtils.mkdir_p(destination) unless File.exist?(destination) destination_migrations = ActiveRecord::Migrator.migrations(destination) last = destination_migrations.last sources.each do |scope, path| source_migrations = ActiveRecord::Migrator.migrations(path) source_migrations.each do |migration| source = File.binread(migration.filename) inserted_comment = "# This migration comes from #{scope} (originally #{migration.version})\n" if /\A#.*\b(?:en)?coding:\s*\S+/ =~ source # If we have a magic comment in the original migration, # insert our comment after the first newline(end of the magic comment line) # so the magic keep working. # Note that magic comments must be at the first line(except sh-bang). source[/\n/] = "\n#{inserted_comment}" else source = "#{inserted_comment}#{source}" end if duplicate = destination_migrations.detect { |m| m.name == migration.name } if options[:on_skip] && duplicate.scope != scope.to_s options[:on_skip].call(scope, migration) end next end migration.version = next_migration_number(last ? last.version + 1 : 0).to_i new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.#{scope}.rb") old_path, migration.filename = migration.filename, new_path last = migration File.binwrite(migration.filename, source) copied << migration options[:on_copy].call(scope, migration, old_path) if options[:on_copy] destination_migrations << migration end end copied end # Finds the correct table name given an Active Record object. # Uses the Active Record object's own table_name, or pre/suffix from the # options passed in. def proper_table_name(name, options = {}) if name.respond_to? :table_name name.table_name else "#{options[:table_name_prefix]}#{name}#{options[:table_name_suffix]}" end end # Determines the version number of the next migration. def next_migration_number(number) if ActiveRecord::Base.timestamped_migrations [Time.now.utc.strftime("%Y%m%d%H%M%S"), "%.14d" % number].max else SchemaMigration.normalize_migration_number(number) end end # Builds a hash for use in ActiveRecord::Migration#proper_table_name using # the Active Record object's table_name prefix and suffix def table_name_options(config = ActiveRecord::Base) #:nodoc: { table_name_prefix: config.table_name_prefix, table_name_suffix: config.table_name_suffix } end private def execute_block if connection.respond_to? :execute_block super # use normal delegation to record the block else yield end end end # MigrationProxy is used to defer loading of the actual migration classes # until they are needed MigrationProxy = Struct.new(:name, :version, :filename, :scope) do def initialize(name, version, filename, scope) super @migration = nil end def basename File.basename(filename) end def mtime File.mtime filename end delegate :migrate, :announce, :write, :disable_ddl_transaction, to: :migration private def migration @migration ||= load_migration end def load_migration require(File.expand_path(filename)) name.constantize.new(name, version) end end class NullMigration < MigrationProxy #:nodoc: def initialize super(nil, 0, nil, nil) end def mtime 0 end end class Migrator#:nodoc: class << self attr_writer :migrations_paths alias :migrations_path= :migrations_paths= def migrate(migrations_paths, target_version = nil, &block) case when target_version.nil? up(migrations_paths, target_version, &block) when current_version == 0 && target_version == 0 [] when current_version > target_version down(migrations_paths, target_version, &block) else up(migrations_paths, target_version, &block) end end def rollback(migrations_paths, steps = 1) move(:down, migrations_paths, steps) end def forward(migrations_paths, steps = 1) move(:up, migrations_paths, steps) end def up(migrations_paths, target_version = nil) migrations = migrations(migrations_paths) migrations.select! { |m| yield m } if block_given? new(:up, migrations, target_version).migrate end def down(migrations_paths, target_version = nil) migrations = migrations(migrations_paths) migrations.select! { |m| yield m } if block_given? new(:down, migrations, target_version).migrate end def run(direction, migrations_paths, target_version) new(direction, migrations(migrations_paths), target_version).run end def open(migrations_paths) new(:up, migrations(migrations_paths), nil) end def schema_migrations_table_name SchemaMigration.table_name end def get_all_versions(connection = Base.connection) if connection.table_exists?(schema_migrations_table_name) SchemaMigration.all.map { |x| x.version.to_i }.sort else [] end end def current_version(connection = Base.connection) get_all_versions(connection).max || 0 end def needs_migration?(connection = Base.connection) (migrations(migrations_paths).collect(&:version) - get_all_versions(connection)).size > 0 end def any_migrations? migrations(migrations_paths).any? end def last_migration #:nodoc: migrations(migrations_paths).last || NullMigration.new end def migrations_paths @migrations_paths ||= ["db/migrate"] # just to not break things if someone uses: migrations_path = some_string Array(@migrations_paths) end def match_to_migration_filename?(filename) # :nodoc: Migration::MigrationFilenameRegexp.match?(File.basename(filename)) end def parse_migration_filename(filename) # :nodoc: File.basename(filename).scan(Migration::MigrationFilenameRegexp).first end def migrations(paths) paths = Array(paths) files = Dir[*paths.map { |p| "#{p}/**/[0-9]*_*.rb" }] migrations = files.map do |file| version, name, scope = parse_migration_filename(file) raise IllegalMigrationNameError.new(file) unless version version = version.to_i name = name.camelize MigrationProxy.new(name, version, file, scope) end migrations.sort_by(&:version) end private def move(direction, migrations_paths, steps) migrator = new(direction, migrations(migrations_paths)) start_index = migrator.migrations.index(migrator.current_migration) if start_index finish = migrator.migrations[start_index + steps] version = finish ? finish.version : 0 send(direction, migrations_paths, version) end end end def initialize(direction, migrations, target_version = nil) raise StandardError.new("This database does not yet support migrations") unless Base.connection.supports_migrations? @direction = direction @target_version = target_version @migrated_versions = nil @migrations = migrations validate(@migrations) Base.connection.initialize_schema_migrations_table Base.connection.initialize_internal_metadata_table end def current_version migrated.max || 0 end def current_migration migrations.detect { |m| m.version == current_version } end alias :current :current_migration def run if use_advisory_lock? with_advisory_lock { run_without_lock } else run_without_lock end end def migrate if use_advisory_lock? with_advisory_lock { migrate_without_lock } else migrate_without_lock end end def runnable runnable = migrations[start..finish] if up? runnable.reject { |m| ran?(m) } else # skip the last migration if we're headed down, but not ALL the way down runnable.pop if target runnable.find_all { |m| ran?(m) } end end def migrations down? ? @migrations.reverse : @migrations.sort_by(&:version) end def pending_migrations already_migrated = migrated migrations.reject { |m| already_migrated.include?(m.version) } end def migrated @migrated_versions || load_migrated end def load_migrated @migrated_versions = Set.new(self.class.get_all_versions) end private # Used for running a specific migration. def run_without_lock migration = migrations.detect { |m| m.version == @target_version } raise UnknownMigrationVersionError.new(@target_version) if migration.nil? result = execute_migration_in_transaction(migration, @direction) record_environment result end # Used for running multiple migrations up to or down to a certain value. def migrate_without_lock if invalid_target? raise UnknownMigrationVersionError.new(@target_version) end result = runnable.each do |migration| execute_migration_in_transaction(migration, @direction) end record_environment result end # Stores the current environment in the database. def record_environment return if down? ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment end def ran?(migration) migrated.include?(migration.version.to_i) end # Return true if a valid version is not provided. def invalid_target? !target && @target_version && @target_version > 0 end def execute_migration_in_transaction(migration, direction) return if down? && !migrated.include?(migration.version.to_i) return if up? && migrated.include?(migration.version.to_i) Base.logger.info "Migrating to #{migration.name} (#{migration.version})" if Base.logger ddl_transaction(migration) do migration.migrate(direction) record_version_state_after_migrating(migration.version) end rescue => e msg = "An error has occurred, " msg << "this and " if use_transaction?(migration) msg << "all later migrations canceled:\n\n#{e}" raise StandardError, msg, e.backtrace end def target migrations.detect { |m| m.version == @target_version } end def finish migrations.index(target) || migrations.size - 1 end def start up? ? 0 : (migrations.index(current) || 0) end def validate(migrations) name , = migrations.group_by(&:name).find { |_, v| v.length > 1 } raise DuplicateMigrationNameError.new(name) if name version , = migrations.group_by(&:version).find { |_, v| v.length > 1 } raise DuplicateMigrationVersionError.new(version) if version end def record_version_state_after_migrating(version) if down? migrated.delete(version) ActiveRecord::SchemaMigration.where(version: version.to_s).delete_all else migrated << version ActiveRecord::SchemaMigration.create!(version: version.to_s) end end def self.last_stored_environment return nil if current_version == 0 raise NoEnvironmentInSchemaError unless ActiveRecord::InternalMetadata.table_exists? environment = ActiveRecord::InternalMetadata[:environment] raise NoEnvironmentInSchemaError unless environment environment end def self.current_environment ActiveRecord::ConnectionHandling::DEFAULT_ENV.call end def self.protected_environment? ActiveRecord::Base.protected_environments.include?(last_stored_environment) if last_stored_environment end def up? @direction == :up end def down? @direction == :down end # Wrap the migration in a transaction only if supported by the adapter. def ddl_transaction(migration) if use_transaction?(migration) Base.transaction { yield } else yield end end def use_transaction?(migration) !migration.disable_ddl_transaction && Base.connection.supports_ddl_transactions? end def use_advisory_lock? Base.connection.supports_advisory_locks? end def with_advisory_lock lock_id = generate_migrator_advisory_lock_id got_lock = Base.connection.get_advisory_lock(lock_id) raise ConcurrentMigrationError unless got_lock load_migrated # reload schema_migrations to be sure it wasn't changed by another process before we got the lock yield ensure Base.connection.release_advisory_lock(lock_id) if got_lock end MIGRATOR_SALT = 2053462845 def generate_migrator_advisory_lock_id db_name_hash = Zlib.crc32(Base.connection.current_database) MIGRATOR_SALT * db_name_hash end end end