Class: ActiveRecord::MigrationContext

Inherits:
Object
  • Object
show all
Defined in:
lib/active_record/migration.rb

Overview

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.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(migrations_paths, schema_migration = nil, internal_metadata = nil) ⇒ MigrationContext

Returns a new instance of MigrationContext.

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# File 'lib/active_record/migration.rb', line 1201

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

Instance Attribute Details

#internal_metadata ⇒ Object (readonly)

Returns the value of attribute internal_metadata.


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# File 'lib/active_record/migration.rb', line 1199

def internal_metadata
  @internal_metadata
end

#migrations_paths ⇒ Object (readonly)

Returns the value of attribute migrations_paths.


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# File 'lib/active_record/migration.rb', line 1199

def migrations_paths
  @migrations_paths
end

#schema_migration ⇒ Object (readonly)

Returns the value of attribute schema_migration.


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# File 'lib/active_record/migration.rb', line 1199

def schema_migration
  @schema_migration
end

Instance Method Details

#current_environment ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1343

def current_environment # :nodoc:
  ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
end

#current_version ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1299

def current_version # :nodoc:
  get_all_versions.max || 0
rescue ActiveRecord::NoDatabaseError
end

#down(target_version = nil, &block) ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1273

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

#forward(steps = 1) ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1259

def forward(steps = 1) # :nodoc:
  move(:up, steps)
end

#get_all_versions ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1291

def get_all_versions # :nodoc:
  if schema_migration.table_exists?
    schema_migration.integer_versions
  else
    []
  end
end

#last_stored_environment ⇒ Object

:nodoc:

Raises:

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# File 'lib/active_record/migration.rb', line 1351

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

#migrate(target_version = nil, &block) ⇒ Object

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.

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# File 'lib/active_record/migration.rb', line 1242

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

#migrations ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1312

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

#migrations_status ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1325

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

#needs_migration? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean)
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# File 'lib/active_record/migration.rb', line 1304

def needs_migration? # :nodoc:
  pending_migration_versions.size > 0
end

#open ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1287

def open # :nodoc:
  Migrator.new(:up, migrations, schema_migration, internal_metadata)
end

#pending_migration_versions ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1308

def pending_migration_versions # :nodoc:
  migrations.collect(&:version) - get_all_versions
end

#protected_environment? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean)
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# File 'lib/active_record/migration.rb', line 1347

def protected_environment? # :nodoc:
  ActiveRecord::Base.protected_environments.include?(last_stored_environment) if last_stored_environment
end

#rollback(steps = 1) ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1255

def rollback(steps = 1) # :nodoc:
  move(:down, steps)
end

#run(direction, target_version) ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1283

def run(direction, target_version) # :nodoc:
  Migrator.new(direction, migrations, schema_migration, internal_metadata, target_version).run
end

#up(target_version = nil, &block) ⇒ Object

:nodoc:

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# File 'lib/active_record/migration.rb', line 1263

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