phpvisual-studio-codexdebugdocker-for-windows
VS Code PHP debugger does not work with Docker
I am trying to setup a development environment with Docker for Windows and VS Code to debug PHP code.
I have created a Docker container from this Dockerfile:
FROM php:8.0.10-apache
RUN pecl install xdebug-3.0.4 && \
docker-php-ext-enable xdebug && \
mkdir /var/log/php && \
chown www-data:www-data /var/log/php && \
chmod 755 /var/log/php && \
{ \
echo ''; \
echo '[xdebug]'; \
echo 'xdebug.mode=develop,debug'; \
echo 'xdebug.client_host=host.docker.internal'; \
echo 'xdebug.start_with_request=yes'; \
echo 'xdebug.log=/var/log/php/xdebug.log'; \
} >> ${PHP_INI_DIR}/conf.d/docker-php-ext-xdebug.ini && \
echo 'error_reporting=E_ALL' >> ${PHP_INI_DIR}/conf.d/error_reporting.ini
When I start the debugger on VS Code and open a PHP file with my browser, the page loads forever even when I don't put any breakpoint in the PHP file.
If I put a breakpoint in the file, the page still loads forever and the debugger does not stop on the breakpoint: step over/into/out icons are greyed out on VS code and the variables table is empty:
If I stop the debugger on VS Code, the page loads successfully.
These are Xdebug's logs:
[17] Log opened at 2021-09-16 10:39:03.887841
[17] [Step Debug] INFO: Connecting to configured address/port: host.docker.internal:9003.
[17] [Step Debug] INFO: Connected to debugging client: host.docker.internal:9003 (through xdebug.client_host/xdebug.client_port). :-)
[17] [Step Debug] -> <init xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug" fileuri="file:///var/www/html/test.php" language="PHP" xdebug:language_version="8.0.10" protocol_version="1.0" appid="17"><engine version="3.0.4"><![CDATA[Xdebug]]></engine><author><![CDATA[Derick Rethans]]></author><url><![CDATA[https://xdebug.org]]></url><copyright><![CDATA[Copyright (c) 2002-2021 by Derick Rethans]]></copyright></init>
[17] [Step Debug] -> <response xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug" status="stopping" reason="ok"></response>
[17] Log closed at 2021-09-16 10:41:00.782334
[18] Log opened at 2021-09-16 10:41:10.195656
[18] [Step Debug] INFO: Connecting to configured address/port: host.docker.internal:9003.
[18] [Step Debug] INFO: Connected to debugging client: host.docker.internal:9003 (through xdebug.client_host/xdebug.client_port). :-)
[18] [Step Debug] -> <init xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug" fileuri="file:///var/www/html/test.php" language="PHP" xdebug:language_version="8.0.10" protocol_version="1.0" appid="18"><engine version="3.0.4"><![CDATA[Xdebug]]></engine><author><![CDATA[Derick Rethans]]></author><url><![CDATA[https://xdebug.org]]></url><copyright><![CDATA[Copyright (c) 2002-2021 by Derick Rethans]]></copyright></init>
[19] Log opened at 2021-09-16 10:42:26.969063
[19] [Step Debug] INFO: Connecting to configured address/port: host.docker.internal:9003.
[19] [Step Debug] INFO: Connected to debugging client: host.docker.internal:9003 (through xdebug.client_host/xdebug.client_port). :-)
[19] [Step Debug] -> <init xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug" fileuri="file:///var/www/html/test.php" language="PHP" xdebug:language_version="8.0.10" protocol_version="1.0" appid="19"><engine version="3.0.4"><![CDATA[Xdebug]]></engine><author><![CDATA[Derick Rethans]]></author><url><![CDATA[https://xdebug.org]]></url><copyright><![CDATA[Copyright (c) 2002-2021 by Derick Rethans]]></copyright></init>
[19] [Step Debug] -> <response xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug" status="stopping" reason="ok"></response>
[19] Log closed at 2021-09-16 10:42:31.116586
[20] Log opened at 2021-09-16 10:42:36.631851
[20] [Step Debug] INFO: Connecting to configured address/port: host.docker.internal:9003.
[20] [Step Debug] ERR: Time-out connecting to debugging client, waited: 200 ms. Tried: host.docker.internal:9003 (through xdebug.client_host/xdebug.client_port) :-(
[20] Log closed at 2021-09-16 10:42:36.835780
[21] Log opened at 2021-09-16 10:42:38.915095
[21] [Step Debug] INFO: Connecting to configured address/port: host.docker.internal:9003.
[21] [Step Debug] INFO: Connected to debugging client: host.docker.internal:9003 (through xdebug.client_host/xdebug.client_port). :-)
[21] [Step Debug] -> <init xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug" fileuri="file:///var/www/html/test.php" language="PHP" xdebug:language_version="8.0.10" protocol_version="1.0" appid="21"><engine version="3.0.4"><![CDATA[Xdebug]]></engine><author><![CDATA[Derick Rethans]]></author><url><![CDATA[https://xdebug.org]]></url><copyright><![CDATA[Copyright (c) 2002-2021 by Derick Rethans]]></copyright></init>
[1049] Log opened at 2021-09-16 10:42:40.727353
[1049] [Step Debug] INFO: Connecting to configured address/port: host.docker.internal:9003.
[1049] [Step Debug] INFO: Connected to debugging client: host.docker.internal:9003 (through xdebug.client_host/xdebug.client_port). :-)
[1049] [Step Debug] -> <init xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug" fileuri="file:///var/www/html/test.php" language="PHP" xdebug:language_version="8.0.10" protocol_version="1.0" appid="1049"><engine version="3.0.4"><![CDATA[Xdebug]]></engine><author><![CDATA[Derick Rethans]]></author><url><![CDATA[https://xdebug.org]]></url><copyright><![CDATA[Copyright (c) 2002-2021 by Derick Rethans]]></copyright></init>
and this is VS Code's launch.json:
{
// Use IntelliSense to learn about possible attributes.
// Hover to view descriptions of existing attributes.
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
"version": "0.2.0",
"configurations": [
{
"name": "Listen for Xdebug",
"type": "php",
"request": "launch",
"port": 9003,
"pathMappings": {
"/var/www/html/": "${workspaceFolder}"
}
},
{
"name": "Launch currently open script",
"type": "php",
"request": "launch",
"program": "${file}",
"cwd": "${fileDirname}",
"port": 0,
"runtimeArgs": [
"-dxdebug.start_with_request=yes"
],
"env": {
"XDEBUG_MODE": "debug,develop",
"XDEBUG_CONFIG": "client_port=${port}"
}
},
{
"name": "Launch Built-in web server",
"type": "php",
"request": "launch",
"runtimeArgs": [
"-dxdebug.mode=debug",
"-dxdebug.start_with_request=yes",
"-S",
"localhost:0"
],
"program": "",
"cwd": "${workspaceRoot}",
"port": 9003,
"serverReadyAction": {
"pattern": "Development Server \\(http://localhost:([0-9]+)\\) started",
"uriFormat": "http://localhost:%s",
"action": "openExternally"
}
}
]
}
Solution
I have finally figured out why the debugger did not work: I launched the debug session inside the container (I connected to it through the Remote - Containers VS Code extension) and not from the Docker host. So, in this case, the correct value for xdebug.client_host is localhost, since both the Xdebug client and the server are on the same host.
To make it work with xdebug.client_host=host.docker.internal, I had set up a Docker volume and I started the debugger directly on Windows, without connecting to the container from inside VS Code. In this case I also had to add a path mapping in the launch.json file, which maps the Docker volume's path to the workspace folder.