From 5c350348d63af1b1cfd807412cc11fc616044da2 Mon Sep 17 00:00:00 2001
From: Francisco Brito <franciscojavierbrito16@gmail.com>
Date: Fri, 15 Mar 2024 15:48:27 -0300
Subject: [PATCH] feature/#7907-script-to-change-local-storage-to-aws

---
 lib/active_storage/migrator.rb            | 35 +++++++++++++++++++++++
 lib/tasks/storage_migrations.rake         | 13 +++++++++
 spec/lib/active_storage/migrator_spec.rb  | 34 ++++++++++++++++++++++
 spec/lib/tasks/storage_migrations_spec.rb | 28 ++++++++++++++++++
 spec/rails_helper.rb                      |  4 +++
 5 files changed, 114 insertions(+)
 create mode 100644 lib/active_storage/migrator.rb
 create mode 100644 lib/tasks/storage_migrations.rake
 create mode 100644 spec/lib/active_storage/migrator_spec.rb
 create mode 100644 spec/lib/tasks/storage_migrations_spec.rb

diff --git a/lib/active_storage/migrator.rb b/lib/active_storage/migrator.rb
new file mode 100644
index 000000000..55787b962
--- /dev/null
+++ b/lib/active_storage/migrator.rb
@@ -0,0 +1,35 @@
+require 'yaml'
+require 'erb'
+
+module ActiveStorage
+  class Migrator
+    def self.migrate(from_service_name, to_service_name)
+      yaml_with_env = ERB.new(File.read('config/storage.yml')).result
+      configs = YAML.load(yaml_with_env)
+
+      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] })
+
+      # Check if services are configured correctly
+      if from_service.nil? || to_service.nil?
+        puts "Error: The services '#{from_service_name}' or '#{to_service_name}' are not configured correctly."
+        return
+      end
+
+      # Configure the blob service for the source service
+      ActiveStorage::Blob.service = from_service
+
+      puts "#{ActiveStorage::Blob.count} Blobs to migrate from #{from_service_name} to #{to_service_name}"
+      ActiveStorage::Blob.find_each do |blob|
+        next unless blob.image?
+
+        print '.'
+
+        blob.open do |io|
+          checksum = blob.checksum
+          to_service.upload(blob.key, io, checksum: checksum)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/tasks/storage_migrations.rake b/lib/tasks/storage_migrations.rake
new file mode 100644
index 000000000..93d085545
--- /dev/null
+++ b/lib/tasks/storage_migrations.rake
@@ -0,0 +1,13 @@
+namespace :storage do
+  desc 'Migrate blobs from one storage service to another'
+  task migrate: :environment do
+    from_service = ENV['FROM']
+    to_service = ENV['TO']
+
+    if from_service.nil? || to_service.nil?
+      raise 'Missing FROM or TO argument. Usage: FROM=service_name TO=service_name rake storage:migrate'
+    end
+
+    ActiveStorage::Migrator.migrate(from_service.to_sym, to_service.to_sym)
+  end
+end
diff --git a/spec/lib/active_storage/migrator_spec.rb b/spec/lib/active_storage/migrator_spec.rb
new file mode 100644
index 000000000..78cd687be
--- /dev/null
+++ b/spec/lib/active_storage/migrator_spec.rb
@@ -0,0 +1,34 @@
+require 'rails_helper'
+
+RSpec.describe ActiveStorage::Migrator do
+  describe '.migrate' do
+    let(:from_service_stub) { double('from_service') }
+    let(:to_service_stub) { double('to_service') }
+    let(:blob_spy) { spy('ActiveStorage::Blob') }
+
+    before do
+      allow(ActiveStorage::Service).to receive(:configure).with(:from_service, any_args).and_return(from_service_stub)
+      allow(ActiveStorage::Service).to receive(:configure).with(:to_service, any_args).and_return(to_service_stub)
+      allow(ActiveStorage::Blob).to receive(:find_each).and_yield(blob_spy)
+    end
+
+    context 'when services are configured correctly' do
+      it 'migrates blobs from one service to another' do
+        allow(blob_spy).to receive(:image?).and_return(true)
+
+        expect(ActiveStorage::Service).to receive(:configure).with(:from_service, any_args)
+        expect(ActiveStorage::Service).to receive(:configure).with(:to_service, any_args)
+
+        described_class.migrate(:from_service, :to_service)
+      end
+    end
+
+    context 'when services are not configured correctly' do
+      it 'prints an error message' do
+        allow(from_service_stub).to receive(:nil?).and_return(true)
+
+        expect { described_class.migrate(:from_service, :to_service) }.to output("Error: The services 'from_service' or 'to_service' are not configured correctly.\n").to_stdout
+      end
+    end
+  end
+end
diff --git a/spec/lib/tasks/storage_migrations_spec.rb b/spec/lib/tasks/storage_migrations_spec.rb
new file mode 100644
index 000000000..6d7d517ed
--- /dev/null
+++ b/spec/lib/tasks/storage_migrations_spec.rb
@@ -0,0 +1,28 @@
+require 'rails_helper'
+require 'rake'
+
+RSpec.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 { Rake::Task['storage:migrate'].invoke }.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 { Rake::Task['storage:migrate'].invoke }.to raise_error(RuntimeError, 'Missing FROM or TO argument. Usage: FROM=service_name TO=service_name rake storage:migrate')
+      end
+    end
+  end
+end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index 616d62d28..0dc019378 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -7,6 +7,10 @@ require 'rspec/rails'
 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'