Changes Requested to Support Discourse on TruffleRuby

bjfish · April 28, 2022, 5:06pm

I would like to request the following 3 changes to help support running Discourse on TruffleRuby:

Change Requested
Update bin/rails to disable unicorn when fork is not supported.

Error

<internal:core> core/kernel.rb:764:in `fork': fork is not available (NotImplementedError)

Files
bin/rails

github.com

discourse/discourse/blob/b266a36967533105215e6848e475c69cb9e36e3e/bin/rails

#!/usr/bin/env ruby
# frozen_string_literal: true

if !ENV["RAILS_ENV"] && (ARGV[0] == "s" || ARGV[0] == "server")
  ENV["UNICORN_PORT"] ||= "3000"

  if ARGV[1] == "-p" && (port = ARGV[2].to_i) > 0
    ENV["UNICORN_PORT"] = port.to_s
  end

  ENV["RAILS_LOGS_STDOUT"] ||= "1"

  exec File.expand_path("unicorn", __dir__)
end

APP_PATH = File.expand_path('../config/application', __dir__)
require_relative '../config/boot'
require 'rails/commands'

Why
TruffleRuby do not support forking.

Suggestion
Disable unicorn if !Process.respond_to?(:fork)

========================================================

Change Requested
Disable mini_profiler for TruffleRuby

Error

<internal:core> core/kernel.rb:236:in `gem_original_require': cannot load such file -- stackprof (LoadError)

Files
config/initializers/006-mini_profiler.rb

github.com

discourse/discourse/blob/b266a36967533105215e6848e475c69cb9e36e3e/config/initializers/006-mini_profiler.rb

# frozen_string_literal: true

# If Mini Profiler is included via gem
if Rails.configuration.respond_to?(:load_mini_profiler) && Rails.configuration.load_mini_profiler
  require 'rack-mini-profiler'
  require 'stackprof'

  begin
    require 'memory_profiler'
  rescue => e
    STDERR.put "#{e} failed to require mini profiler"
  end

  # initialization is skipped so trigger it
  Rack::MiniProfilerRails.initialize!(Rails.application)
end

if defined?(Rack::MiniProfiler) && defined?(Rack::MiniProfiler::Config)
  # note, we may want to add some extra security here that disables mini profiler in a multi hosted env unless user global admin
  #   raw_connection means results are not namespaced

This file has been truncated. show original

Why
Stackprof is not currently supported on TruffleRuby

Suggestion
Disable mini_profiler loading when RUBY_ENGINE is “TruffleRuby”

========================================================

Change Requested
Prevent rbtrace from loading

Similar usages already preventing rb_trace from loading:

github.com

discourse/discourse/blob/b266a36967533105215e6848e475c69cb9e36e3e/config/application.rb#L264

      
        
                          discourse/tests/test-boot-rails.js
                          wizard/test/test_helper.js
                        }.include?(logical_path) ||
                        logical_path =~ /\/node_modules/ ||
                        logical_path =~ /\/dist/
                    end
                  end
                end
            
            
    if ENV['RBTRACE'] == "1"
                  require 'rbtrace'
                end
            
            
    config.generators do |g|
                  g.test_framework :rspec, fixture: false
                end
              end
            end

github.com

discourse/discourse/blob/b266a36967533105215e6848e475c69cb9e36e3e/config/environments/development.rb#L80

      
        
              config.hosts.concat(hosts.split(","))
            end
            
            
require 'middleware/turbo_dev'
            config.middleware.insert 0, Middleware::TurboDev
            require 'middleware/missing_avatars'
            config.middleware.insert 1, Middleware::MissingAvatars
            
            
config.enable_anon_caching = false
            if RUBY_ENGINE == "ruby"
              require 'rbtrace'
            end
            
            
if emails = GlobalSetting.developer_emails
              config.developer_emails = emails.split(",").map(&:downcase).map(&:strip)
            end
            
            
if ENV["DISCOURSE_SKIP_CSS_WATCHER"] != "1" && (defined?(Rails::Server) || defined?(Puma) || defined?(Unicorn))
              require 'stylesheet/watcher'
              STDERR.puts "Starting CSS change watcher"
              @watcher = Stylesheet::Watcher.watch

Error
Failure/Error: require ‘rbtrace’

Suggestion
Use one of the methods in the above links to prevent loading rbtrace

Files
spec/rails_helper.rb

github.com

discourse/discourse/blob/b266a36967533105215e6848e475c69cb9e36e3e/spec/rails_helper.rb#L16

      
        
              SimpleCov.start 'rails' do
                add_group 'Libraries', /^\/lib\/(?!tasks).*$/
                add_group 'Scripts', 'script'
                add_group 'Serializers', 'app/serializers'
                add_group 'Services', 'app/services'
                add_group 'Tasks', 'lib/tasks'
              end
            end
            
            
require 'rubygems'
            require 'rbtrace'
            require 'pry'
            require 'pry-byebug'
            require 'pry-rails'
            require 'fabrication'
            require 'mocha/api'
            require 'certified'
            require 'webmock/rspec'
            
            
class RspecErrorTracker
              def self.last_exception=(ex)

gerhard · April 29, 2022, 12:12pm

Those seem like reasonable requests.

BTW: Has anything changed about mini_racer not being supported on TruffleRuby? That’s a major blocker.

bjfish · April 29, 2022, 6:55pm

BTW: Has anything changed about mini_racer not being supported on TruffleRuby? That’s a major blocker.

I have a branch with most of the mini_racer functionality passing the test suite using using GraalJS for TruffleRuby. I believe it handles all of the functionality needed for Discourse. It just needs to be reviewed and I’ll then I’ll try to get it merged. This is how I’ve been running it locally: x.com

bjfish · May 2, 2022, 3:44pm

Correction:
Disable mini_profiler loading when RUBY_ENGINE is “truffleruby”

sam · May 3, 2022, 5:04am

mini_profiler should still be fine, I would recommend just having us not load rbtrace / stackprof etc. There are loose dependencies.

mini_profiler can still provide plenty value in truffle world, nothing MRI specific about this.

gerhard · May 4, 2022, 8:10pm

Here’s a PR with the requested changes.

I still couldn’t get it to run successfully, there was a java.lang.NullPointerException, but that might be just me crudely disabling mini_racer. I’m really looking forward to seeing a fully functional Discourse running on TruffleRuby.

I didn’t look into this any further, but I noticed an error when I only disabled loading of stackprof and memory_profiler. So I completely disabled mini_profiler for now.

2022-05-04 21:48:13 +0200 Rack app ("POST /mini-profiler-resources/results" - (127.0.0.1)): #<SystemStackError: stack level too deep
        from StackOverflowCheckImpl.java:328:in `com.oracle.svm.core.graal.snippets.StackOverflowCheckImpl.newStackOverflowError0'>

It might have been a side effect of other problems. I guess we could investigate when other problems are solved.

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