Add multi-tenancy support

README.md

@@ -144,6 +144,20 @@ This task will prompt you to choose one of the three options:
 
 Based on your selection, a post-checkout hook will be installed or updated in your `.git/hooks` folder.
 
+## Multi-Tenancy Support
+
+If your application uses multiple schemas or tenants, you can configure ActualDbSchema to manage migrations across all schemas by adding the following to your initializer file (`config/initializers/actual_db_schema.rb`):
+
+```ruby
+ActualDbSchema.config[:multi_tenant_schemas] = -> { # list of all active schemas }
+```
+
+### Example:
+
+```ruby
+ActualDbSchema.config[:multi_tenant_schemas] = -> { ["public", "tenant1", "tenant2"] }
+```
+
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

lib/actual_db_schema.rb

@@ -14,6 +14,7 @@
 require_relative "actual_db_schema/patches/migrator"
 require_relative "actual_db_schema/patches/migration_context"
 require_relative "actual_db_schema/git_hooks"
+require_relative "actual_db_schema/multi_tenant"
 
 require_relative "actual_db_schema/commands/base"
 require_relative "actual_db_schema/commands/rollback"

lib/actual_db_schema/commands/rollback.rb

@@ -17,7 +17,7 @@ def initialize(context, manual_mode: false)
       def call_impl
         rolled_back = context.rollback_branches(manual_mode: @manual_mode)
 
-        return unless rolled_back
+        return unless rolled_back || ActualDbSchema.failed.any?
 
         ActualDbSchema.failed.empty? ? print_success : print_error
       end
@@ -43,11 +43,10 @@ def print_error
 
       def failed_migrations_list
         ActualDbSchema.failed.map.with_index(1) do |failed, index|
-          <<~MIGRATION
-            #{colorize("Migration ##{index}:", :yellow)}
-              File: #{failed.short_filename}
-              Branch: #{failed.branch}
-          MIGRATION
+          migration_details = colorize("Migration ##{index}:\n", :yellow)
+          migration_details += "  File: #{failed.short_filename}\n"
+          migration_details += "  Schema: #{failed.schema}\n" if failed.schema
+          migration_details + "  Branch: #{failed.branch}\n"
         end.join("\n")
       end
 

lib/actual_db_schema/failed_migration.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module ActualDbSchema
-  FailedMigration = Struct.new(:migration, :exception, :branch, keyword_init: true) do
+  FailedMigration = Struct.new(:migration, :exception, :branch, :schema, keyword_init: true) do
     def filename
       migration.filename
     end

lib/actual_db_schema/multi_tenant.rb

@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module ActualDbSchema
+  # Handles multi-tenancy support by switching schemas for supported databases
+  module MultiTenant
+    include ActualDbSchema::OutputFormatter
+
+    class << self
+      def with_schema(schema_name)
+        context = switch_schema(schema_name)
+        yield
+      ensure
+        restore_context(context)
+      end
+
+      private
+
+      def adapter_name
+        ActiveRecord::Base.connection.adapter_name
+      end
+
+      def switch_schema(schema_name)
+        case adapter_name
+        when /postgresql/i
+          switch_postgresql_schema(schema_name)
+        when /mysql/i
+          switch_mysql_schema(schema_name)
+        else
+          message = "[ActualDbSchema] Multi-tenancy not supported for adapter: #{adapter_name}. " \
+            "Proceeding without schema switching."
+          puts colorize(message, :gray)
+        end
+      end
+
+      def switch_postgresql_schema(schema_name)
+        old_search_path = ActiveRecord::Base.connection.schema_search_path
+        ActiveRecord::Base.connection.schema_search_path = schema_name
+        { type: :postgresql, old_context: old_search_path }
+      end
+
+      def switch_mysql_schema(schema_name)
+        old_db = ActiveRecord::Base.connection.current_database
+        ActiveRecord::Base.connection.execute("USE #{ActiveRecord::Base.connection.quote_table_name(schema_name)}")
+        { type: :mysql, old_context: old_db }
+      end
+
+      def restore_context(context)
+        return unless context
+
+        case context[:type]
+        when :postgresql
+          ActiveRecord::Base.connection.schema_search_path = context[:old_context] if context[:old_context]
+        when :mysql
+          return unless context[:old_context]
+
+          ActiveRecord::Base.connection.execute(
+            "USE #{ActiveRecord::Base.connection.quote_table_name(context[:old_context])}"
+          )
+        end
+      end
+    end
+  end
+end

lib/actual_db_schema/patches/migration_context.rb

@@ -3,23 +3,21 @@
 module ActualDbSchema
   module Patches
     # Add new command to roll back the phantom migrations
-    module MigrationContext
+    module MigrationContext # rubocop:disable Metrics/ModuleLength
       include ActualDbSchema::OutputFormatter
 
       def rollback_branches(manual_mode: false)
-        rolled_back = false
+        schemas = multi_tenant_schemas&.call || []
+        schema_count = schemas.any? ? schemas.size : 1
 
-        phantom_migrations.reverse_each do |migration|
-          next unless status_up?(migration)
+        rolled_back_migrations = if schemas.any?
+                                   rollback_multi_tenant(schemas, manual_mode: manual_mode)
+                                 else
+                                   rollback_branches_for_schema(manual_mode: manual_mode)
+                                 end
 
-          rolled_back = true
-          show_info_for(migration) if manual_mode
-          migrate(migration) if !manual_mode || user_wants_rollback?
-        rescue StandardError => e
-          handle_rollback_error(migration, e)
-        end
-
-        rolled_back
+        delete_migrations(rolled_back_migrations, schema_count)
+        rolled_back_migrations.any?
       end
 
       def phantom_migrations
@@ -34,6 +32,32 @@ def phantom_migrations
 
       private
 
+      def rollback_branches_for_schema(manual_mode: false, schema_name: nil, rolled_back_migrations: [])
+        phantom_migrations.reverse_each do |migration|
+          next unless status_up?(migration)
+
+          show_info_for(migration, schema_name) if manual_mode
+          migrate(migration, rolled_back_migrations, schema_name) if !manual_mode || user_wants_rollback?
+        rescue StandardError => e
+          handle_rollback_error(migration, e, schema_name)
+        end
+
+        rolled_back_migrations
+      end
+
+      def rollback_multi_tenant(schemas, manual_mode: false)
+        all_rolled_back_migrations = []
+
+        schemas.each do |schema_name|
+          ActualDbSchema::MultiTenant.with_schema(schema_name) do
+            rollback_branches_for_schema(manual_mode: manual_mode, schema_name: schema_name,
+                                         rolled_back_migrations: all_rolled_back_migrations)
+          end
+        end
+
+        all_rolled_back_migrations
+      end
+
       def down_migrator_for(migration)
         if ActiveRecord::Migration.current_version < 6
           ActiveRecord::Migrator.new(:down, [migration], migration.version)
@@ -69,26 +93,29 @@ def user_wants_rollback?
         answer[0] == "y"
       end
 
-      def show_info_for(migration)
+      def show_info_for(migration, schema_name = nil)
         puts colorize("\n[ActualDbSchema] A phantom migration was found and is about to be rolled back.", :gray)
         puts "Please make a decision from the options below to proceed.\n\n"
+        puts "Schema: #{schema_name}" if schema_name
         puts "Branch: #{branch_for(migration.version.to_s)}"
         puts "Database: #{ActualDbSchema.db_config[:database]}"
         puts "Version: #{migration.version}\n\n"
         puts File.read(migration.filename)
       end
 
-      def migrate(migration)
+      def migrate(migration, rolled_back_migrations, schema_name = nil)
         migration.name = extract_class_name(migration.filename)
 
-        message = "[ActualDbSchema] Rolling back phantom migration #{migration.version} #{migration.name} " \
-            "(from branch: #{branch_for(migration.version.to_s)})"
+        message = "[ActualDbSchema]"
+        message += " #{schema_name}:" if schema_name
+        message += " Rolling back phantom migration #{migration.version} #{migration.name} " \
+                   "(from branch: #{branch_for(migration.version.to_s)})"
         puts colorize(message, :gray)
 
         migrator = down_migrator_for(migration)
         migrator.extend(ActualDbSchema::Patches::Migrator)
         migrator.migrate
-        File.delete(migration.filename)
+        rolled_back_migrations << migration
       end
 
       def extract_class_name(filename)
@@ -104,7 +131,7 @@ def metadata
         @metadata ||= ActualDbSchema::Store.instance.read
       end
 
-      def handle_rollback_error(migration, exception)
+      def handle_rollback_error(migration, exception, schema_name = nil)
         error_message = <<~ERROR
           Error encountered during rollback:
 
@@ -115,7 +142,8 @@ def handle_rollback_error(migration, exception)
         ActualDbSchema.failed << FailedMigration.new(
           migration: migration,
           exception: exception,
-          branch: branch_for(migration.version.to_s)
+          branch: branch_for(migration.version.to_s),
+          schema: schema_name
         )
       end
 
@@ -127,6 +155,21 @@ def cleaned_exception_message(message)
 
         patterns_to_remove.reduce(message.strip) { |msg, pattern| msg.gsub(pattern, "").strip }
       end
+
+      def delete_migrations(migrations, schema_count)
+        migration_counts = migrations.each_with_object(Hash.new(0)) do |migration, hash|
+          hash[migration.filename] += 1
+        end
+
+        migrations.uniq.each do |migration|
+          count = migration_counts[migration.filename]
+          File.delete(migration.filename) if count == schema_count && File.exist?(migration.filename)
+        end
+      end
+
+      def multi_tenant_schemas
+        ActualDbSchema.config[:multi_tenant_schemas]
+      end
     end
   end
 end