unknown attribute 'service_name' for ActiveStorage::Blob - ruby-on-rails-6

Question

After I upgraded from Rails 5 to 6.1, the ActiveStorage raises an error:
unknown attribute 'service_name' for ActiveStorage::Blob.
Why, and how can I fix it?

Answer 1

These commands worked for me.
rails active_storage:update
rails db:migrate

Answer 2

Gemfile without the error:
gem 'rails', '~> 6.0.2'
Gemfile with the error:
gem 'rails', github: 'rails/rails', branch: 'master'
If you were already using active_storage and want to update your rails version to 6.1.0alpha, you have to run
rails active_storage:update
this will give you 2 new active_storage migrations that are needed for active_storage to work properly.
Migration 1:
# This migration comes from active_storage (originally 20190112182829)
class AddServiceNameToActiveStorageBlobs < ActiveRecord::Migration[6.0]
def up
unless column_exists?(:active_storage_blobs, :service_name)
add_column :active_storage_blobs, :service_name, :string
if configured_service = ActiveStorage::Blob.service.name
ActiveStorage::Blob.unscoped.update_all(service_name: configured_service)
end
change_column :active_storage_blobs, :service_name, :string, null: false
end
end
end
Migration 2:
# This migration comes from active_storage (originally 20191206030411)
class CreateActiveStorageVariantRecords < ActiveRecord::Migration[6.0]
def up
create_table :active_storage_variant_records do |t|
t.belongs_to :blob, null: false, index: false
t.string :variation_digest, null: false
t.index %i[ blob_id variation_digest ], name: "index_active_storage_variant_records_uniqueness", unique: true
t.foreign_key :active_storage_blobs, column: :blob_id
end
end
end
Than you just run
rails db:migrate
It works.

Answer 3

This is taken care of in the normal upgrade process:
rails app:update
rails db:migrate
This solution to the service_name change gets a mention in the 6.1 Release Notes. The rails app:update task calls the internal rails active_storage:update for you since Rails 6.0.0 (source).

Answer 4

step 1:
rm 20191021084642_create_active_storage_tables.active_storage.rb
step 2:
rails active_storage:install
step 3:
rails db:migrate