[#224] Support custom data migration template

[bazay]

Implements feature request in issue: #224

Todo

• Test feature from Rails app

Testing Notes

The following code snippets are taken from a personal Rails application using this feature branch as gem source.

config/initializers/data_migrate.rb

DataMigrate.configure do |config|
  config.data_migrations_path = "db/maintenance/"
  config.data_template_path = Rails.root.join("lib/maintenance/maintenance_migration_template.rb")
end

lib/maintenance/maintenance_migration_template.rb

# frozen_string_literal: true

class <%= migration_class_name %> < <%= migration_base_class_name %>
  def up
    # Call you migration task from here
    #
    # For example:
    # params = {
    #   key: "value",
    # }
    #
    # Maintenance::MyTask.perform_later(**params)
  end

  def down
    raise ActiveRecord::IrreversibleMigration
  end
end

Running the generator:

$ bin/rails g data_migration MaintenanceTest                                                                                                                                                     add-data-migrate
      create  db/maintenance/20221121162436_maintenance_test.rb

where
db/maintenance/20221121162436_maintenance_test.rb
contains

class MaintenanceTest < ActiveRecord::Migration[7.0]
  def up
    # Call you migration task from here
    #
    # For example:
    # params = {
    #   key: "value",
    # }
    #
    # Maintenance::MyTask.perform_later(**params)
  end

  def down
    raise ActiveRecord::IrreversibleMigration
  end
end

I can also confirm that removing config.data_template_path from config/initializers/data_migrate.rb will use the default template.

[bazay]

Performing validation on the setter seems a bit unorthodox, alternatively this can be performed from within the data migration generator i.e. https://github.com/ilyakatz/data-migrate/pull/232/files#diff-a4575045875fb9b1c551bd2d20696bd405d5c84ed26c2c773a895ce660c392ceR30

[ilyakatz]

i like the idea of doing validation here so that the error is raised on startup and devs will know right away that something is wrong. so looks good to me

[ilyakatz]

Thank you, merged and deployed!