How do I use helper methods in a Migration?

Question

How do I use a helper method like this from application_helper.rb:

def upload_s3(region, file, bucket, filepath)
   s3 = Aws::S3::Resource.new(region: region)
   obj = s3.bucket(bucket).object(filepath)
   obj.upload_file(file)
end

Inside of a migration:

class CreateSeeds < ActiveRecord::Migration[6.0]
   pdf = "https://#{bucket}.s3.#{region}.amazonaws.com/#{record["filepath"]}"
   name = tokenize_by_delimiter_case(".", record["filepath"], 0)
   path = "items/#{name}"
   upload_s3(region, pdf, bucket, path)
end

I know I can use a model's method but I don't want to copy and paste a bunch of the same methods in models just for migrations...otherwise I wouldn't have the helpers in the first place.

I get this error when trying to run my migration:

NoMethodError: undefined method `upload_s3' for #<CreateSeeds:0x00007fe4ee12bbc0>

Answer 1

I would encourage you to organize things differently and create a service class to handle these things, this is really not what migrations and helpers are for. If you create a service class in e.g. app/services you could call that from a rake test easily.

Your helper

module TestHelper
  def test
    puts 'TEST'
  end
end

your migration, the include has to be outside the migration definition

include TestHelper

class Test < ActiveRecord::Migration[6.0]
  def change
    test
  end
end