cannot connect to xdebug - `Connection to the debugger has been closed`

I’m trying to connect to xdebug on a remote VM, but it just fails instantly with “Connection to the debugger has been closed”. I created github repo with a Vagrant VM which reproduces this issue. Once up and running, the VM is reachable at 33.33.33.10 and has xdebug loaded (it appears in phpinfo output ). I have also checked that xdebug.ini is parsed.

Logging doesn’t help much:

- [Info] {Fri 19 2013 11:59:14} Connection to the debugger has been closed

Looking through the source code, it seems this message is shown when a socket is closed, but I don’t know where to go from here.

vdebug settings:

g:vdebug_options      
{'debug_file': 'vdebug_log',
'debug_file_level': 2,
'watch_window_style': 'expanded',
'marker_default': '*',
'continuous_mode': 0,
'ide_key': '',
'break_on_open': 1,
'on_close': 'detach',
'path_maps': {'/var/www': 'C:\code\xdebug-test'},
'marker_closed_tree': '+',
'timeout': 20,
'port': 9000,
'marker_open_tree': '-',
'debug_window_level': 1,
'server': '33.33.33.10'}

Also, here’s some output from Apache’s access.log:

33.33.33.1 - - [19/Apr/2013:12:26:11 +0100] "GET /debug_me.php HTTP/1.1" 200 314 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0"

[nathanielks]

@Iazel you’re a lifesaver. My understanding of remote_port was the same as yours before. That totally makes sense now!

[iazel]

Hello guys! I’m trying to use docker and this error popup. My current vdebug_options:

let g:vdebug_options = {
      \ 'port': '9001',
      \ "server": '',
      \ 'ide_key': '', 
      \ 'path_maps': {'/var/www/html': expand('<sfile>:h:p')}, 
      \ 'debug_file': '/tmp/vdebug.log', 
      \ 'debug_file_level': 2 
      \ }

However in the log there’s no useful information, only this:

- [Info] {lun 01 2016 12:22:53} Connection to the debugger has been closed

My Dockerfile configuration:

FROM php:7-fpm
RUN yes | pecl install xdebug
ADD ./xdebug.ini /usr/local/etc/php/conf.d/xdebug.ini

The xdebug.ini:

xdebug.remote_enable=1;
xdebug.remote_port=9001;
xdebug.remote_connect_back=1;
xdebug.max_nesting_level=200
xdebug.idekey=""
zend_extension=/usr/local/lib/php/extensions/no-debug-non-zts-20151012/xdebug.so

This is the relevant bit of the docker-compose.yml

php:
    build: ./docker/php/
    expose:
        - 9000
    ports:
        - '9001:9001'
    links:
        - mysql
    volumes_from:
        - app

Any ideas?

Solved

Ok, it seems I wasn’t understanding what remote_port means. I thought it was the port where the debugger was listening to (like node --debug), but It turns out is the other way around and it should be the port on the local machine, the one from which we initiate the debugging! Removing the port bind on 9001 has done the trick, and even more, using docker we can use the default 9000 port 😃

Corret docker-compose.yml:

php:
    build: ./docker/php/
    expose:
        - 9000 # needed by nginx + fpm
    links:
        - mysql
    volumes_from:
        - app

And the xdebug.ini can be shortened to

xdebug.remote_enable=1;
xdebug.remote_connect_back=1;
zend_extension=/usr/local/lib/php/extensions/no-debug-non-zts-20151012/xdebug.so