require "active_support/core_ext/module/attribute_accessors"
require 'set'
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\tbin/rake db:migrate RAILS_ENV=#{::Rails.env}.")
elsif !message
super("Migrations are pending. To resolve this issue, run:\n\n\tbin/rake 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
# = 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): Sets a
# default value for +column_name+ definded by +default+ on +table_name+.
# * 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
# rake 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
# rake 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. rake 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
subclass.include Compatibility::Legacy
end
end
def self.[](version)
version = version.to_s
name = "V#{version.tr('.', '_')}"
unless Compatibility.const_defined?(name)
versions = Compatibility.constants.grep(/\AV[0-9_]+\z/).map { |s| s.to_s.delete('V').tr('_', '.').inspect }
raise "Unknown migration version #{version.inspect}; expected one of #{versions.sort.join(', ')}"
end
Compatibility.const_get(name)
end
def self.current_version
Rails.version.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/rake 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
class ReversibleBlockHelper < Struct.new(:reverting) # :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
class MigrationProxy < Struct.new(:name, :version, :filename, :scope)
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)
ActiveSupport::Deprecation.silence do
if connection.table_exists?(schema_migrations_table_name)
SchemaMigration.all.map { |x| x.version.to_i }.sort
else
[]
end
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:
File.basename(filename) =~ Migration::MigrationFilenameRegexp
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
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
def run_without_lock
migration = migrations.detect { |m| m.version == @target_version }
raise UnknownMigrationVersionError.new(@target_version) if migration.nil?
unless (up? && migrated.include?(migration.version.to_i)) || (down? && !migrated.include?(migration.version.to_i))
begin
execute_migration_in_transaction(migration, @direction)
rescue => e
canceled_msg = use_transaction?(migration) ? ", this migration was canceled" : ""
raise StandardError, "An error has occurred#{canceled_msg}:\n\n#{e}", e.backtrace
end
end
end
def migrate_without_lock
if !target && @target_version && @target_version > 0
raise UnknownMigrationVersionError.new(@target_version)
end
runnable.each do |migration|
Base.logger.info "Migrating to #{migration.name} (#{migration.version})" if Base.logger
begin
execute_migration_in_transaction(migration, @direction)
rescue => e
canceled_msg = use_transaction?(migration) ? "this and " : ""
raise StandardError, "An error has occurred, #{canceled_msg}all later migrations canceled:\n\n#{e}", e.backtrace
end
end
end
def ran?(migration)
migrated.include?(migration.version.to_i)
end
def execute_migration_in_transaction(migration, direction)
ddl_transaction(migration) do
migration.migrate(direction)
record_version_state_after_migrating(migration.version)
end
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 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