Add ability to configure whether background migrations should be run …

…inline

CHANGELOG.md

@@ -1,5 +1,13 @@
 ## master (unreleased)
 
+- Add ability to configure whether background migrations should be run inline
+
+    The previous behavior of running inline in development and test environments is preserved, unless overriden.
+
+    ```ruby
+    config.run_background_migrations_inline = -> { Rails.env.local? }
+    ```
+
 ## 0.13.1 (2024-01-23)
 
 - Fix calculation of batch ranges for background migration created with explicit ranges

docs/configuring.md

@@ -214,6 +214,17 @@ Add to an initializer file:
 config.auto_analyze = true
 ```
 
+### Running background migrations inline
+
+`config.run_background_migrations_inline` can be configured with a proc to decide whether background migrations should be run inline. For convenience defaults to true for development and test environments.
+
+```ruby
+# config/initializers/online_migrations.rb
+config.run_background_migrations_inline = -> { Rails.env.local? }
+```
+
+Set to `nil` to avoid running background migrations inline.
+
 ## Schema Sanity
 
 Columns can flip order in `db/schema.rb` when you have multiple developers. One way to prevent this is to [alphabetize them](https://www.pgrs.net/2008/03/12/alphabetize-schema-rb-columns/).

lib/generators/online_migrations/templates/initializer.rb.tt

@@ -77,6 +77,10 @@ OnlineMigrations.configure do |config|
   #   end
   # end
 
+  # Decide whether background migrations should be run inline.
+  # Convenient for development and test environments.
+  config.run_background_migrations_inline = -> { Rails.env.local? }
+
   # ==> Background migrations configuration
 
   # The path where generated background migrations will be placed.

lib/online_migrations/background_migrations/migration_helpers.rb

@@ -372,8 +372,8 @@ def perform_action_on_relation_in_background(model_name, conditions, action, upd
       def enqueue_background_migration(migration_name, *arguments, **options)
         migration = create_background_migration(migration_name, *arguments, **options)
 
-        # For convenience in dev/test environments
-        if Utils.developer_env?
+        run_inline = OnlineMigrations.config.run_background_migrations_inline
+        if run_inline && run_inline.call
           runner = MigrationRunner.new(migration)
           runner.run_all_migration_jobs
         end

lib/online_migrations/config.rb

@@ -171,6 +171,16 @@ def target_version
     #
     attr_accessor :verbose_sql_logs
 
+    # The proc which decides whether background migrations should be run inline.
+    # For convenience defaults to true for development and test environments.
+    #
+    # @example
+    #   OnlineMigrations.config.run_background_migrations_inline = -> { Rails.env.local? }
+    #
+    # @return [Proc]
+    #
+    attr_accessor :run_background_migrations_inline
+
     # Configuration object to configure background migrations
     #
     # @return [BackgroundMigrationsConfig]
@@ -202,6 +212,7 @@ def initialize
       @alphabetize_schema = false
       @enabled_checks = @error_messages.keys.index_with({})
       @verbose_sql_logs = defined?(Rails.env) && (Rails.env.production? || Rails.env.staging?)
+      @run_background_migrations_inline = -> { Utils.developer_env? }
     end
 
     def lock_retrier=(value)

test/schema_statements/misc_test.rb

@@ -170,6 +170,43 @@ def test_enqueue_background_migration
       assert_equal OnlineMigrations.config.background_migrations.batch_size, m.batch_size
     end
 
+    def test_run_background_migrations_inline_true_in_local
+      user = User.create!
+      assert_nil user.admin
+
+      @connection.enqueue_background_migration("MakeAllNonAdmins")
+
+      m = OnlineMigrations::BackgroundMigrations::Migration.last
+      assert m.succeeded?
+      assert_equal false, user.reload.admin
+    end
+
+    def test_run_background_migrations_inline_configured_to_nil
+      user = User.create!
+      assert_nil user.admin
+
+      OnlineMigrations.config.stub(:run_background_migrations_inline, nil) do
+        @connection.enqueue_background_migration("MakeAllNonAdmins")
+      end
+
+      m = OnlineMigrations::BackgroundMigrations::Migration.last
+      assert m.enqueued?
+      assert_nil user.reload.admin
+    end
+
+    def test_run_background_migrations_inline_configured_to_custom_proc
+      user = User.create!
+      assert_nil user.admin
+
+      OnlineMigrations.config.stub(:run_background_migrations_inline, -> { false }) do
+        @connection.enqueue_background_migration("MakeAllNonAdmins")
+      end
+
+      m = OnlineMigrations::BackgroundMigrations::Migration.last
+      assert m.enqueued?
+      assert_nil user.reload.admin
+    end
+
     def test_disable_statement_timeout
       prev_value = get_statement_timeout
       set_statement_timeout(10)