Debug PHP in Docker with PHPStorm and Xdebug

README.md

Debug your PHP in Docker with Intellij/PHPStorm and Xdebug

1. For your local dev, create a Dockerfile that is based on your production image and simply install xdebug into it. Exemple:

FROM php:5

RUN yes | pecl install xdebug \
    && echo "zend_extension=$(find /usr/local/lib/php/extensions/ -name xdebug.so)" > /usr/local/etc/php/conf.d/xdebug.ini \
    && echo "xdebug.remote_enable=on" >> /usr/local/etc/php/conf.d/xdebug.ini \
    && echo "xdebug.remote_autostart=off" >> /usr/local/etc/php/conf.d/xdebug.ini

2. Get you local IP address (ifconfig or such)
3. Start your container with the following environment variable: XDEBUG_CONFIG="remote_host={{YOUR_IP_ADDRESS}}"

• Simple docker run: docker run -e XDEBUG_CONFIG="remote_host={{YOUR_IP_ADDRESS}}" your-image

• With docker-compose:

  # docker-compose.yml
  foo:
    build: path/to/Dockerfile
    environment:
      XDEBUG_CONFIG: remote_host={{YOUR_IP_ADDRESS}}

4. In Intellij/PHPStorm go to: Languages & Frameworks > PHP > Debug > DBGp Proxy and set the following settings:

• Host: your IP address
• Port: 9000

Then you're all set and can start listening for PHP Debug connections from your IDE. On the first run it will ask you to map your local directoryies to the docker directories, but after that nothing will be required anymore!

Happy debugging!

The key here is to now start using host.docker.internal in your remote_host configuration moving forward. Also, I think remote_connect_back is not necessary and should be removed. I've consolidated a simplified but generic explanation where I try to focus strictly on configuring Xdebug to work in Docker, if anyone is interested:

Using Xdebug in Docker (gist)

I did this because even though the core solution for Docker-specific setups is pretty simple (i.e. remote_host=host.docker.internal), any extra code, configuration details or unrelated bugs can start to make things very confusing for beginners who are diving into Docker for the first time. If anything, it'll at least help me for future reference 😄

Is it possible to setup connection by next chain: Windows -> Linux (host Docker) -> Docker Linux PHP with PHPUnit ?

MacOS:

[xdebug]
xdebug.remote_host = "docker.for.mac.host.internal"
xdebug.default_enable = 1
xdebug.remote_autostart = 1
xdebug.remote_connect_back = 0
xdebug.remote_enable = 1
xdebug.remote_handler = "dbgp"
xdebug.remote_port = 9000

Linux:

[xdebug]
xdebug.remote_host = "172.18.0.1"
xdebug.default_enable = 1
xdebug.remote_autostart = 1
xdebug.remote_connect_back = 0
xdebug.remote_enable = 1
xdebug.remote_handler = "dbgp"
xdebug.remote_port = 9000

Windows:

[xdebug]
xdebug.remote_host = "docker.for.win.host.internal"
xdebug.default_enable = 1
xdebug.remote_autostart = 1
xdebug.remote_connect_back = 0
xdebug.remote_enable = 1
xdebug.remote_handler = "dbgp"
xdebug.remote_port = 9000

This one is working for me, just replacing the "remote_host" with the value from:

docker network inspect bridge | grep Gateway

sudo iptables -A INPUT -p tcp --dport 9000 -j ACCEPT

If you have problems with running it on Linux (Ubuntu in my case) & you have a firewall enabled then the solution for you may be opening firewall ports for connection to port 9000 on docker service
sudo ufw enable && sudo ufw allow in from 172.16.0.0/12 to any port 9000 comment xdebug

You can check this discussion for more information

Here is a quick reference for XDebug 3 and Docker Gist.

The main change to the xdebug.ini file is:

[XDebug]
zend_extension=xdebug.so

xdebug.mode = debug
xdebug.start_with_request=yes
xdebug.client_host=host.docker.internal