# frozen_string_literal: true
require "benchmark"
require "set"
require "zlib"
require "active_support/core_ext/array/access"
require "active_support/core_ext/enumerable"
require "active_support/core_ext/module/attribute_accessors"
require "active_support/actionable_error"
require "active_record/migration/pending_migration_connection"
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[7.1]
# 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[7.1]
# 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[7.1]
# 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:
include ActiveSupport::ActionableError
action "Run pending migrations" do
ActiveRecord::Tasks::DatabaseTasks.migrate
if ActiveRecord.dump_schema_after_migration
connection = ActiveRecord::Tasks::DatabaseTasks.migration_connection
ActiveRecord::Tasks::DatabaseTasks.dump_schema(connection.pool.db_config)
end
end
def initialize(message = nil, pending_migrations: nil)
if pending_migrations.nil?
connection = ActiveRecord::Tasks::DatabaseTasks.migration_connection
pending_migrations = connection.migration_context.open.pending_migrations
end
super(message || detailed_migration_message(pending_migrations))
end
private
def detailed_migration_message(pending_migrations)
message = "Migrations are pending. To resolve this issue, run:\n\n bin/rails db:migrate"
message += " RAILS_ENV=#{::Rails.env}" if defined?(Rails.env) && !Rails.env.local?
message += "\n\n"
message += "You have #{pending_migrations.size} pending #{pending_migrations.size > 1 ? 'migrations:' : 'migration:'}\n\n"
pending_migrations.each do |pending_migration|
message += "#{pending_migration.filename}\n"
end
message
end
def connection
ActiveRecord::Tasks::DatabaseTasks.migration_connection
end
end
class ConcurrentMigrationError < MigrationError # :nodoc:
DEFAULT_MESSAGE = "Cannot run migrations because another migration process is currently running."
RELEASE_LOCK_FAILED_MESSAGE = "Failed to release advisory lock"
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
class EnvironmentStorageError < ActiveRecordError # :nodoc:
def initialize
msg = +"You are attempting to store the environment in a database where metadata is disabled.\n"
msg << "Check your database configuration to see if this is intended."
super(msg)
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[7.1]
# 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[7.1]
# 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, to_table = nil, **options): 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
# bin/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.
#
# bin/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[7.1]
# def change
# add_column :tablenames, :fieldname, :string
# end
# end
#
# To run migrations against the currently configured database, use
# bin/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 command, 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
# bin/rails db:rollback 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. bin/rails db:rollback 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.
#
# == More examples
#
# Not all migrations change the schema. Some just fix the data:
#
# class RemoveEmptyTags < ActiveRecord::Migration[7.1]
# 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[7.1]
# 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[7.1]
# 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[7.1]
# 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[7.1]
# 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 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[7.1]
# 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"
autoload :JoinTable, "active_record/migration/join_table"
autoload :ExecutionStrategy, "active_record/migration/execution_strategy"
autoload :DefaultStrategy, "active_record/migration/default_strategy"
# This must be defined before the inherited hook, below
class Current < Migration # :nodoc:
def create_table(table_name, **options)
if block_given?
super { |t| yield compatible_table_definition(t) }
else
super
end
end
def change_table(table_name, **options)
if block_given?
super { |t| yield compatible_table_definition(t) }
else
super
end
end
def create_join_table(table_1, table_2, **options)
if block_given?
super { |t| yield compatible_table_definition(t) }
else
super
end
end
def drop_table(table_name, **options)
if block_given?
super { |t| yield compatible_table_definition(t) }
else
super
end
end
def compatible_table_definition(t)
t
end
end
def self.inherited(subclass) # :nodoc:
super
if subclass.superclass == Migration
major = ActiveRecord::VERSION::MAJOR
minor = ActiveRecord::VERSION::MINOR
raise StandardError, "Directly inheriting from ActiveRecord::Migration is not supported. " \
"Please specify the Active Record release the migration was written for:\n" \
"\n" \
" class #{subclass} < ActiveRecord::Migration[#{major}.#{minor}]"
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:
def self.valid_version_format?(version_string) # :nodoc:
[
MigrationFilenameRegexp,
/\A\d(_?\d)*\z/ # integer with optional underscores
].any? { |pattern| pattern.match?(version_string) }
end
# 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, file_watcher: ActiveSupport::FileUpdateChecker)
@app = app
@needs_check = true
@mutex = Mutex.new
@file_watcher = file_watcher
end
def call(env)
@mutex.synchronize do
@watcher ||= build_watcher do
@needs_check = true
ActiveRecord::Migration.check_pending_migrations
@needs_check = false
end
if @needs_check
@watcher.execute
else
@watcher.execute_if_updated
end
end
@app.call(env)
end
private
def build_watcher(&block)
current_environment = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
all_configs = ActiveRecord::Base.configurations.configs_for(env_name: current_environment)
paths = all_configs.flat_map { |config| config.migrations_paths || Migrator.migrations_paths }.uniq
@file_watcher.new([], paths.index_with(["rb"]), &block)
end
def connection
ActiveRecord::Tasks::DatabaseTasks.migration_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.
#
# This is deprecated in favor of +check_all_pending!+
def check_pending!(connection = ActiveRecord::Tasks::DatabaseTasks.migration_connection)
ActiveRecord.deprecator.warn(<<-MSG.squish)
The `check_pending!` method is deprecated in favor of `check_all_pending!`. The
new implementation will loop through all available database configurations and find
pending migrations. The prior implementation did not permit this.
MSG
pending_migrations = connection.migration_context.open.pending_migrations
if pending_migrations.any?
raise ActiveRecord::PendingMigrationError.new(pending_migrations: pending_migrations)
end
end
# Raises ActiveRecord::PendingMigrationError error if any migrations are pending
# for all database configurations in an environment.
def check_all_pending!
pending_migrations = []
ActiveRecord::Tasks::DatabaseTasks.with_temporary_connection_for_each(env: env) do |connection|
if pending = connection.migration_context.open.pending_migrations
pending_migrations << pending
end
end
migrations = pending_migrations.flatten
if migrations.any?
raise ActiveRecord::PendingMigrationError.new(pending_migrations: migrations)
end
end
def load_schema_if_pending!
if any_schema_needs_update?
# Roundtrip to Rake to allow plugins to hook into database initialization.
root = defined?(ENGINE_ROOT) ? ENGINE_ROOT : Rails.root
FileUtils.cd(root) do
Base.connection_handler.clear_all_connections!(:all)
system("bin/rails db:test:prepare")
end
end
check_pending_migrations
end
def maintain_test_schema! # :nodoc:
if ActiveRecord.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
ruby2_keywords(:method_missing)
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
def check_pending_migrations # :nodoc:
migrations = pending_migrations
if migrations.any?
raise ActiveRecord::PendingMigrationError.new(pending_migrations: migrations)
end
end
private
def any_schema_needs_update?
!db_configs_in_current_env.all? do |db_config|
Tasks::DatabaseTasks.schema_up_to_date?(db_config, ActiveRecord.schema_format)
end
end
def db_configs_in_current_env
ActiveRecord::Base.configurations.configs_for(env_name: env)
end
def pending_migrations
pending_migrations = []
ActiveRecord::Base.configurations.configs_for(env_name: env).each do |db_config|
ActiveRecord::PendingMigrationConnection.establish_temporary_connection(db_config) do |conn|
if pending = conn.migration_context.open.pending_migrations
pending_migrations << pending
end
end
end
pending_migrations.flatten
end
def env
ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
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
def execution_strategy
@execution_strategy ||= ActiveRecord.migration_strategy.new(self)
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[7.1]
# 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[7.1]
# def change
# revert TenderloveMigration
#
# create_table(:apples) do |t|
# t.string :variety
# end
# end
# end
#
# This command can be nested.
def revert(*migration_classes, &block)
run(*migration_classes.reverse, revert: true) unless migration_classes.empty?
if block_given?
if connection.respond_to? :revert
connection.revert(&block)
else
recorder = command_recorder
@connection = recorder
suppress_messages do
connection.revert(&block)
end
@connection = recorder.delegate
recorder.replay(self)
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[7.1]
# 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
# Used to specify an operation that is only run when migrating up
# (for example, populating a new column with its initial values).
#
# In the following example, the new column +published+ will be given
# the value +true+ for all existing records.
#
# class AddPublishedToPosts < ActiveRecord::Migration[7.1]
# def change
# add_column :posts, :published, :boolean, default: false
# up_only do
# execute "update posts set published = 'true'"
# end
# end
# end
def up_only(&block)
execute_block(&block) unless reverting?
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::Tasks::DatabaseTasks.migration_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
public_send(direction)
end
ensure
@connection = nil
@execution_strategy = 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
# Takes a message argument and outputs it as is.
# A second boolean argument can be passed to specify whether to indent or not.
def say(message, subitem = false)
write "#{subitem ? " ->" : "--"} #{message}"
end
# Outputs text along with how long it took to run its block.
# If the block returns an integer it assumes it is the number of rows affected.
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
# Takes a block as an argument and suppresses any output generated by the block.
def suppress_messages
save, self.verbose = verbose, false
yield
ensure
self.verbose = save
end
def connection
@connection || ActiveRecord::Tasks::DatabaseTasks.migration_connection
end
def method_missing(method, *arguments, &block)
say_with_time "#{method}(#{format_arguments(arguments)})" 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 method == :rename_table ||
(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 execution_strategy.respond_to?(method)
execution_strategy.send(method, *arguments, &block)
end
end
ruby2_keywords(:method_missing)
def copy(destination, sources, options = {})
copied = []
FileUtils.mkdir_p(destination) unless File.exist?(destination)
schema_migration = SchemaMigration::NullSchemaMigration.new
internal_metadata = InternalMetadata::NullInternalMetadata.new
destination_migrations = ActiveRecord::MigrationContext.new(destination, schema_migration, internal_metadata).migrations
last = destination_migrations.last
sources.each do |scope, path|
source_migrations = ActiveRecord::MigrationContext.new(path, schema_migration, internal_metadata).migrations
source_migrations.each do |migration|
source = File.binread(migration.filename)
inserted_comment = "# This migration comes from #{scope} (originally #{migration.version})\n"
magic_comments = +""
loop do
# 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.sub!(/\A(?:#.*\b(?:en)?coding:\s*\S+|#\s*frozen_string_literal:\s*(?:true|false)).*\n/) do |magic_comment|
magic_comments << magic_comment; ""
end || break
end
if !magic_comments.empty? && source.start_with?("\n")
magic_comments << "\n"
source = source[1..-1]
end
source = "#{magic_comments}#{inserted_comment}#{source}"
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.timestamped_migrations
[Time.now.utc.strftime("%Y%m%d%H%M%S"), "%.14d" % number].max
else
"%.3d" % number.to_i
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
def format_arguments(arguments)
arg_list = arguments[0...-1].map(&:inspect)
last_arg = arguments.last
if last_arg.is_a?(Hash)
last_arg = last_arg.reject { |k, _v| internal_option?(k) }
arg_list << last_arg.inspect unless last_arg.empty?
else
arg_list << last_arg.inspect
end
arg_list.join(", ")
end
def internal_option?(option_name)
option_name.start_with?("_")
end
def command_recorder
CommandRecorder.new(connection)
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
delegate :migrate, :announce, :write, :disable_ddl_transaction, to: :migration
private
def migration
@migration ||= load_migration
end
def load_migration
Object.send(:remove_const, name) rescue nil
load(File.expand_path(filename))
name.constantize.new(name, version)
end
end
# = \Migration \Context
#
# MigrationContext sets the context in which a migration is run.
#
# A migration context requires the path to the migrations is set
# in the +migrations_paths+ parameter. Optionally a +schema_migration+
# class can be provided. Multiple database applications will instantiate
# a +SchemaMigration+ object per database. From the Rake tasks, \Rails will
# handle this for you.
class MigrationContext
attr_reader :migrations_paths, :schema_migration, :internal_metadata
def initialize(migrations_paths, schema_migration = nil, internal_metadata = nil)
if schema_migration == SchemaMigration
ActiveRecord.deprecator.warn(<<-MSG.squish)
SchemaMigration no longer inherits from ActiveRecord::Base. If you want
to use the default connection, remove this argument. If you want to use a
specific connection, instantiate MigrationContext with the connection's schema
migration, for example `MigrationContext.new(path, Dog.connection.schema_migration)`.
MSG
schema_migration = nil
end
if internal_metadata == InternalMetadata
ActiveRecord.deprecator.warn(<<-MSG.squish)
SchemaMigration no longer inherits from ActiveRecord::Base. If you want
to use the default connection, remove this argument. If you want to use a
specific connection, instantiate MigrationContext with the connection's internal
metadata, for example `MigrationContext.new(path, nil, Dog.connection.internal_metadata)`.
MSG
internal_metadata = nil
end
@migrations_paths = migrations_paths
@schema_migration = schema_migration || SchemaMigration.new(connection)
@internal_metadata = internal_metadata || InternalMetadata.new(connection)
end
# Runs the migrations in the +migrations_path+.
#
# If +target_version+ is +nil+, +migrate+ will run +up+.
#
# If the +current_version+ and +target_version+ are both
# 0 then an empty array will be returned and no migrations
# will be run.
#
# If the +current_version+ in the schema is greater than
# the +target_version+, then +down+ will be run.
#
# If none of the conditions are met, +up+ will be run with
# the +target_version+.
def migrate(target_version = nil, &block)
case
when target_version.nil?
up(target_version, &block)
when current_version == 0 && target_version == 0
[]
when current_version > target_version
down(target_version, &block)
else
up(target_version, &block)
end
end
def rollback(steps = 1) # :nodoc:
move(:down, steps)
end
def forward(steps = 1) # :nodoc:
move(:up, steps)
end
def up(target_version = nil, &block) # :nodoc:
selected_migrations = if block_given?
migrations.select(&block)
else
migrations
end
Migrator.new(:up, selected_migrations, schema_migration, internal_metadata, target_version).migrate
end
def down(target_version = nil, &block) # :nodoc:
selected_migrations = if block_given?
migrations.select(&block)
else
migrations
end
Migrator.new(:down, selected_migrations, schema_migration, internal_metadata, target_version).migrate
end
def run(direction, target_version) # :nodoc:
Migrator.new(direction, migrations, schema_migration, internal_metadata, target_version).run
end
def open # :nodoc:
Migrator.new(:up, migrations, schema_migration, internal_metadata)
end
def get_all_versions # :nodoc:
if schema_migration.table_exists?
schema_migration.integer_versions
else
[]
end
end
def current_version # :nodoc:
get_all_versions.max || 0
rescue ActiveRecord::NoDatabaseError
end
def needs_migration? # :nodoc:
pending_migration_versions.size > 0
end
def pending_migration_versions # :nodoc:
migrations.collect(&:version) - get_all_versions
end
def migrations # :nodoc:
migrations = migration_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
def migrations_status # :nodoc:
db_list = schema_migration.normalized_versions
file_list = migration_files.filter_map do |file|
version, name, scope = parse_migration_filename(file)
raise IllegalMigrationNameError.new(file) unless version
version = schema_migration.normalize_migration_number(version)
status = db_list.delete(version) ? "up" : "down"
[status, version, (name + scope).humanize]
end
db_list.map! do |version|
["up", version, "********** NO FILE **********"]
end
(db_list + file_list).sort_by { |_, version, _| version.to_i }
end
def current_environment # :nodoc:
ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
end
def protected_environment? # :nodoc:
ActiveRecord::Base.protected_environments.include?(last_stored_environment) if last_stored_environment
end
def last_stored_environment # :nodoc:
return nil unless connection.internal_metadata.enabled?
return nil if current_version == 0
raise NoEnvironmentInSchemaError unless connection.internal_metadata.table_exists?
environment = connection.internal_metadata[:environment]
raise NoEnvironmentInSchemaError unless environment
environment
end
private
def connection
ActiveRecord::Tasks::DatabaseTasks.migration_connection
end
def migration_files
paths = Array(migrations_paths)
Dir[*paths.flat_map { |path| "#{path}/**/[0-9]*_*.rb" }]
end
def parse_migration_filename(filename)
File.basename(filename).scan(Migration::MigrationFilenameRegexp).first
end
def move(direction, steps)
migrator = Migrator.new(direction, migrations, schema_migration, internal_metadata)
if current_version != 0 && !migrator.current_migration
raise UnknownMigrationVersionError.new(current_version)
end
start_index =
if current_version == 0
0
else
migrator.migrations.index(migrator.current_migration)
end
finish = migrator.migrations[start_index + steps]
version = finish ? finish.version : 0
public_send(direction, version)
end
end
class Migrator # :nodoc:
class << self
attr_accessor :migrations_paths
# For cases where a table doesn't exist like loading from schema cache
def current_version
connection = ActiveRecord::Tasks::DatabaseTasks.migration_connection
schema_migration = SchemaMigration.new(connection)
internal_metadata = InternalMetadata.new(connection)
MigrationContext.new(migrations_paths, schema_migration, internal_metadata).current_version
end
end
self.migrations_paths = ["db/migrate"]
def initialize(direction, migrations, schema_migration, internal_metadata, target_version = nil)
@direction = direction
@target_version = target_version
@migrated_versions = nil
@migrations = migrations
@schema_migration = schema_migration
@internal_metadata = internal_metadata
validate(@migrations)
@schema_migration.create_table
@internal_metadata.create_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(@schema_migration.integer_versions)
end
private
def connection
ActiveRecord::Tasks::DatabaseTasks.migration_connection
end
# 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?
record_environment
execute_migration_in_transaction(migration)
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
record_environment
runnable.each(&method(:execute_migration_in_transaction))
end
# Stores the current environment in the database.
def record_environment
return if down?
@internal_metadata[:environment] = connection.pool.db_config.env_name
end
def ran?(migration)
migrated.include?(migration.version.to_i)
end
# Return true if a valid version is not provided.
def invalid_target?
@target_version && @target_version != 0 && !target
end
def execute_migration_in_transaction(migration)
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)
@schema_migration.delete_version(version.to_s)
else
migrated << version
@schema_migration.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, &block)
if use_transaction?(migration)
connection.transaction(&block)
else
yield
end
end
def use_transaction?(migration)
!migration.disable_ddl_transaction && connection.supports_ddl_transactions?
end
def use_advisory_lock?
connection.advisory_locks_enabled?
end
def with_advisory_lock
lock_id = generate_migrator_advisory_lock_id
got_lock = 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
if got_lock && !connection.release_advisory_lock(lock_id)
raise ConcurrentMigrationError.new(
ConcurrentMigrationError::RELEASE_LOCK_FAILED_MESSAGE
)
end
end
MIGRATOR_SALT = 2053462845
def generate_migrator_advisory_lock_id
db_name_hash = Zlib.crc32(connection.current_database)
MIGRATOR_SALT * db_name_hash
end
end
end