Poll success, but error: Operation now in progress (29). when Xdebug trying connect to PhpStorm from docker container

Question

I'm trying debug CLI script, and Xdebug can't connect to PhpStorm.
I see error Operation now in progress (29). in Xdebug remote log.
I'm sure Xdebug configured right, but I don't know how to debug PhpStorm.

Summary from phpinfo() generated by https://xdebug.org/wizard.php

Tailored Installation Instructions
Summary
Xdebug installed: 2.6.1
Server API: Command Line Interface
Windows: no
Zend Server: no
PHP Version: 7.1.24
Zend API nr: 320160303
PHP API nr: 20160303
Debug Build: no
Thread Safe Build: no
OPcache Loaded: no
Configuration File Path: /usr/local/etc/php
Configuration File: /usr/local/etc/php/php.ini
Extensions directory: /usr/local/lib/php/extensions/no-debug-non-zts-20160303
You're already running the latest Xdebug version

Xdebug log

Log opened at 2019-02-19 11:59:37
I: Connecting to configured address/port: 46.201.50.194:9000.
W: Creating socket for '46.201.50.194:9000', poll success, but error: Operation now in progress (29).
E: Could not connect to client. :-(
Log closed at 2019-02-19 11:59:37

Xdebug config

xdebug

xdebug support => enabled
Version => 2.6.1
IDE Key => PHPSTORM

Supported protocols
DBGp - Common DeBuGger Protocol

Directive => Local Value => Master Value
xdebug.auto_trace => Off => Off
xdebug.cli_color => 0 => 0
xdebug.collect_assignments => Off => Off
xdebug.collect_includes => On => On
xdebug.collect_params => 0 => 0
xdebug.collect_return => Off => Off
xdebug.collect_vars => Off => Off
xdebug.coverage_enable => On => On
xdebug.default_enable => On => On
xdebug.dump.COOKIE => no value => no value
xdebug.dump.ENV => no value => no value
xdebug.dump.FILES => no value => no value
xdebug.dump.GET => no value => no value
xdebug.dump.POST => no value => no value
xdebug.dump.REQUEST => no value => no value
xdebug.dump.SERVER => no value => no value
xdebug.dump.SESSION => no value => no value
xdebug.dump_globals => On => On
xdebug.dump_once => On => On
xdebug.dump_undefined => Off => Off
xdebug.extended_info => On => On
xdebug.file_link_format => no value => no value
xdebug.filename_format => no value => no value
xdebug.force_display_errors => Off => Off
xdebug.force_error_reporting => 0 => 0
xdebug.gc_stats_enable => Off => Off
xdebug.gc_stats_output_dir => /tmp => /tmp
xdebug.gc_stats_output_name => gcstats.%p => gcstats.%p
xdebug.halt_level => 0 => 0
xdebug.idekey => PHPSTORM => PHPSTORM
xdebug.max_nesting_level => 256 => 256
xdebug.max_stack_frames => -1 => -1
xdebug.overload_var_dump => 2 => 2
xdebug.profiler_aggregate => Off => Off
xdebug.profiler_append => Off => Off
xdebug.profiler_enable => Off => Off
xdebug.profiler_enable_trigger => Off => Off
xdebug.profiler_enable_trigger_value => no value => no value
xdebug.profiler_output_dir => /tmp => /tmp
xdebug.profiler_output_name => cachegrind.out.%p => cachegrind.out.%p
xdebug.remote_addr_header => no value => no value
xdebug.remote_autostart => On => On
xdebug.remote_connect_back => Off => Off
xdebug.remote_cookie_expire_time => 3600 => 3600
xdebug.remote_enable => On => On
xdebug.remote_handler => dbgp => dbgp
xdebug.remote_host => 127.0.0.1 => localhost
xdebug.remote_log => /app/xdebug.log => no value
xdebug.remote_mode => req => req
xdebug.remote_port => 9000 => 9000
xdebug.remote_timeout => 200 => 200
xdebug.scream => Off => Off
xdebug.show_error_trace => Off => Off
xdebug.show_exception_trace => Off => Off
xdebug.show_local_vars => Off => Off
xdebug.show_mem_delta => Off => Off
xdebug.trace_enable_trigger => Off => Off
xdebug.trace_enable_trigger_value => no value => no value
xdebug.trace_format => 0 => 0
xdebug.trace_options => 0 => 0
xdebug.trace_output_dir => /tmp => /tmp
xdebug.trace_output_name => trace.%c => trace.%c
xdebug.var_display_max_children => 128 => 128
xdebug.var_display_max_data => 512 => 512
xdebug.var_display_max_depth => 3 => 3

Answer 1

Xdebug can't connect to PhpStorm because PhpStorm was not reachable by my external host ip. How I debug it. First I checked from docker container that PhpStorm listen port (9000 in my case)

nc -vz external_ip 9000

It got (tcp) failed: Connection refused
I try the same from the host and also got the error Then I tried from host

nc -vz localhost 9000

And I got [tcp/*] succeeded! So the problem in xdebug.remote_host not in PhpStorm probably

I found host ip in container

netstat -nr | grep '^0\.0\.0\.0' | awk '{print $2}'

Put it in xdebug.remote_host and now it works correctly

Thanks for @LazyOne

Answer 2

In my case I simply set the following xdebug conf:

xdebug.remote_connect_back=0
xdebug.remote_host=host.docker.internal

host.docker.internal should 'magically' find the host's IP (cf. documentation). Note that this requires Docker v18.03+ and currently only works on Mac and Windows hosts.