Can't start remote debug server undefined method `wait_connection=' for Byebug:Module (NoMethodError)

[jessesanford]

When I try to start the remote server following the guide I get the following with every version of byebug > 5.x:

undefined method `wait_connection=' for Byebug:Module (NoMethodError)

relevant code:

  require 'byebug'
  Byebug.wait_connection = true
  Byebug.start_server('localhost', 8989)

[guilherme]

to help:

i've discovered that:

require 'byebug/core'
Byebug.wait_connection = true
Byebug.start_server('localhost', 8989)

works.

and if you try:

require 'byebug'
debugger
Byebug.wait_connection = true
Byebug.start_server('localhost', 8989)

works too.

It works because "debugger" calls: Byebug.attach(https://github.com/deivid-rodriguez/byebug/blob/master/lib/byebug/attacher.rb), which calls require 'byebug/core' which requires the remote part.

I wonder if: https://github.com/deivid-rodriguez/byebug/blob/master/lib/byebug.rb should require 'byebug/core' ?

[deivid-rodriguez]

Indeed. This was changed in b77855c to speed up library loading. I didn't notice that it would break remote debugging.

I thinking we could add another kernel method remote_byebug to make setting this up easier and less likely to break, that would do the whole

require 'byebug/core'
Byebug.wait_connection = true
Byebug.start_server('localhost', 8989)

For now, follow @guilherme's fix! 😃

[raphi]

👍

[donnoman]

I had a hard time launching the remote debugger ONLY when I wanted it launched. It was further complicated that I got some other error when calling 'debugger' as one of the previous posters mentioned.

This is what I had to do, in order to start the debugger on a multi-process unicorn and connect to it with the byebug remote client.

I added the following to the class under test.

The order of the requires was important. Using the :: to denote top level class was also important.

  def self.remote_debugger
    require "byebug/core"
    port = begin
      server = TCPServer.new(nil, 0)
      server.addr[1]
    ensure
      server.close if server
    end
    puts "Remote debugger on port #{port}"
    ::Byebug.wait_connection = true
    ::Byebug.start_server('localhost', port)
    require "byebug"
  end

Now to trigger the debugger where I wanted it also in this class. I couldn't call 'debugger' here. I had to ::Byebug.byebug to avoid that naming conflict. This was deep in a mailer view with Rails and Devise.

  # http://stackoverflow.com/questions/14286601/resque-and-resque-mailer-with-devise
  def self.perform(action, *args)
    remote_debugger
    ::Byebug.byebug
    # Hack to prevent RuntimeError - Could not find a valid mapping for admin.attributes
    record_wrapper = args.shift
    record_hash = args.shift
...

I really wish the remote debugger server and client were reversed, or were supported in such a fashion. Such that I could just start the debugger cli listening at a specific port and it would wait until the app contacted it, it could debug then when done wait for the next debugger call.

Then in the app when triggering a breakpoint, it connects to the cli. That way it wouldn't matter which process was being debugged.

[donnoman]

I was able to revise my hack

  module Byebug
    class << self
      def start_remote_debugging
        require "byebug/core"
        require "byebug"
        port = begin
          server = TCPServer.new(nil, 0)
          server.addr[1]
        ensure
          server.close if server
        end
        "Remote debugger on port #{port}".tap do |message|
          puts message
          Rails.logger.warn message
        end
        self.wait_connection = true
        start_server('localhost', port)
        attach
      end
    end
  end

then later

def some_method_somewhere
  Byebug.start_remote_debugging
...

which spits out something like

Remote debugger on port 51737

bundle exec byebug -R 51737

[cben]

@donnoman The TCPServer part is just to find an unused port, right?
After #277 gets merged you should be able to simply do

self.wait_connection = true
start_server('localhost', 0) do
  puts "Remote debugger on port #{Byebug.actual_port}"
end

[deivid-rodriguez]

This was improved via #406. Now you can use remote_byebug to start the remote debugger.