Sprockets does not require SQL files for custom rake task

Question

Based on this article, which describes how to use Sprockets to write small SQL manifest files, I have my SQL views and functions automatically re-created on every rake db:migrate. This worked wonderfully until the last upgrade to Rails 5.1

Suddenly the manifest files get compiled, however every single *= require statement is ignored and I end up with an empty manifest file. I've tried several comment styles for the DirectiveProcessor, with and without file extensions, with and without relative paths. No matter what I provide, I end up with an empty file that gets executed via the DB.

my setup

db/functions/application.sql

/*
 * This is a manifest file that'll be compiled into application.sql, which will include all the files
 * from db/functions listed below.
 *
 *= require kill_all_connections.sql
 *= require invalidate_emails.sql
 *
 *= require days_until_birthday.sql
*/

lib/tasks/db_functions.rake

namespace :db do
  desc 'creates DB functions listed in db/functions.sql'
  task :functions => :environment do
    sprocket_env = Sprockets::Environment.new do |env|
      env.register_mime_type('text/sql', '.sql')
      env.register_processor('text/sql', Sprockets::DirectiveProcessor)
      env.append_path 'db/functions'
    end

    ActiveRecord::Base.connection.execute(sprocket_env['application.sql'].to_s)
  end
end

my result

looking at the console when I execute rails db:functions, I see the following:

(69.2ms)  /*
* This is a manifest file that'll be compiled into application.sql, which will include all the files
* from db/functions listed below.
*


*

*/

So the file gets executed but looks empty... Anyone has any ideas?

Answer 1

Isn't Sprockets a bit overkill for the task of simply merging a bunch of files?

namespace :db do
  desc 'creates DB functions listed in db/functions.sql'
  task :functions => :environment do
    File.open(Rails.root.join('db','functions.sql'), 'w') do |dest|
      Dir[Rails.root.join('db', 'functions', '*.sql')].each do |f|
        File.copy_stream(f, dest)
      end
    end
    # ...
  end
end

If you need to have them in a specific order (to manage dependencies) just use an array instead of Dir[Rails.root.join('db', 'functions', '*.sql')].

Answer 2

Try adding the following line to the Sprockets environment configuration block:

env.register_bundle_processor 'text/sql', Sprockets::Bundle

Also, you can add the following line to support single-line SQL comments:

env.register_preprocessor 'text/sql', Sprockets::DirectiveProcessor.new(comments: ['--', ['/*', '*/']])