feat: Script to migrate images between providers

lib/active_storage/migrator.rb

@@ -0,0 +1,60 @@
+require 'yaml'
+require 'erb'
+require 'logger'
+
+class ActiveStorage::Migrator
+  Rails.logger = Logger.new($stdout)
+  Rails.logger.level = Logger::DEBUG
+
+  def self.migrate(from_service_name, to_service_name)
+    configs = load_storage_config
+    # Check if services are configured correctly
+    if configs[from_service_name.to_s].nil? || configs[to_service_name.to_s].nil?
+      raise "Error: The services '#{from_service_name}' or '#{to_service_name}' are not configured correctly."
+    end
+
+    from_service = ActiveStorage::Service.configure(from_service_name, { from_service_name.to_sym => configs[from_service_name.to_s] })
+    to_service = ActiveStorage::Service.configure(to_service_name, { to_service_name.to_sym => configs[to_service_name.to_s] })
+
+    configure_blob_service(from_service)
+
+    Rails.logger.debug { "#{ActiveStorage::Blob.count} Blobs to migrate from #{from_service_name} to #{to_service_name}" }
+
+    migrate_blobs(from_service, to_service)
+  end
+
+  def self.load_storage_config
+    yaml_with_env = ERB.new(File.read('config/storage.yml')).result
+    YAML.load(yaml_with_env)
+  end
+
+  def self.configure_services(from_service_name, to_service_name, configs)
+    from_service = ActiveStorage::Service.configure(from_service_name, { from_service_name.to_sym => configs[from_service_name.to_s] })
+    to_service = ActiveStorage::Service.configure(to_service_name, { to_service_name.to_sym => configs[to_service_name.to_s] })
+    [from_service, to_service]
+  end
+
+  def self.configure_service(service_name, configs)
+    service_config = configs[service_name.to_s]
+    ActiveStorage::Service.configure(service_name, { service_name.to_sym => service_config })
+  end
+
+  def self.configure_blob_service(service)
+    ActiveStorage::Blob.service = service
+  end
+
+  def self.migrate_blobs(_from_service, to_service)
+    # Configure the blob service for the source service
+    ActiveStorage::Blob.find_each do |blob|
+      next unless blob.image?
+
+      Rails.logger.debug { '.' }
+
+      blob.open do |io|
+        checksum = blob.checksum
+        to_service.upload(blob.key, io, checksum: checksum)
+      end
+    end
+    Rails.logger.debug { 'Successful migration' }
+  end
+end

lib/tasks/storage_migrations.rake

@@ -0,0 +1,11 @@
+namespace :storage do
+  desc 'Migrate blobs from one storage service to another'
+  task migrate: :environment do
+    from_service = ENV.fetch('FROM', nil)
+    to_service = ENV.fetch('TO', nil)
+
+    raise 'Missing FROM or TO argument. Usage: FROM=service_name TO=service_name rake storage:migrate' if from_service.nil? || to_service.nil?
+
+    ActiveStorage::Migrator.migrate(from_service.to_sym, to_service.to_sym)
+  end
+end

spec/lib/active_storage/migrator_spec.rb

@@ -0,0 +1,31 @@
+require 'rails_helper'
+
+RSpec.describe ActiveStorage::Migrator do
+  describe '.migrate' do
+    let(:from_service_stub) { instance_double(ActiveStorage::Service) }
+    let(:to_service_stub) { instance_double(ActiveStorage::Service) }
+
+    before do
+      allow(ActiveStorage::Service).to receive(:configure).with('local', any_args).and_return(from_service_stub)
+      allow(ActiveStorage::Service).to receive(:configure).with('amazon', any_args).and_return(to_service_stub)
+    end
+
+    context 'when services are configured correctly' do
+      it 'migrates blobs from one service to another' do
+        expect(ActiveStorage::Service).to receive(:configure).with('local', any_args)
+        expect(ActiveStorage::Service).to receive(:configure).with('amazon', any_args)
+        expect(described_class).to receive(:migrate_blobs).with(from_service_stub, to_service_stub)
+        expect { described_class.migrate('local', 'amazon') }.not_to raise_error
+      end
+    end
+
+    context 'when services are not configured correctly' do
+      it 'prints an error message' do
+        allow(ActiveStorage::Service).to receive(:configure).and_return(nil)
+        expect do
+          described_class.migrate('random', 'random')
+        end.to raise_error(RuntimeError, "Error: The services 'random' or 'random' are not configured correctly.")
+      end
+    end
+  end
+end

spec/lib/tasks/rake/task_storage_migrations_spec.rb

@@ -0,0 +1,35 @@
+require 'rake'
+require 'rails_helper'
+
+RSpec.describe Rake::Task do
+  describe 'storage_migrations' do
+    describe 'rake task' do
+      context 'when FROM argument is missing' do
+        before do
+          ENV['FROM'] = nil
+        end
+
+        it 'raises an error' do
+          expect do
+            described_class['storage:migrate'].invoke
+          end.to raise_error(RuntimeError,
+                             'Missing FROM or TO argument. Usage: FROM=service_name TO=service_name rake storage:migrate')
+        end
+      end
+
+      context 'when TO argument is missing' do
+        before do
+          ENV['FROM'] = 'service_name'
+          ENV['TO'] = nil
+        end
+
+        it 'raises an error' do
+          expect do
+            described_class['storage:migrate'].invoke
+          end.to raise_error(RuntimeError,
+                             'Missing FROM or TO argument. Usage: FROM=service_name TO=service_name rake storage:migrate')
+        end
+      end
+    end
+  end
+end

spec/rails_helper.rb

@@ -7,6 +7,10 @@
 require 'pundit/rspec'
 require 'sidekiq/testing'
 
+# Load Rake tasks
+require 'rake'
+Rails.application.load_tasks
+
 # test-prof helpers for tests optimization
 require 'test_prof/recipes/rspec/before_all'
 require 'test_prof/recipes/rspec/let_it_be'