We are on Linux (Fedora v30), as Stanislas guide us (using Macintosh) @ : https://github.com/angristan/php-xdebug-docker
seems that Xdebug loaded at phpinfo();
but there is no communication with the out world except container. In detail, setuping Xdebug into a container means that we doing remote debugging. The problem in his example is that provide the DockerIP using the const host.docker.internal, where is not exists on linux.
On Docker for Windows (and Mac), there is a magic hostname host.docker.internal that containers can use to connect to services on the host. There’s no direct equivalent in Linux Docker.
This easily can be validated by searching Docker Docs https://docs.docker.com/search/?q=host.docker.internal returns only these two https://docs.docker.com/docker-for-mac/networking/ https://docs.docker.com/docker-for-windows/networking/
There are different ways getting the DockerIP
1) As Stanislas guide linked us : https://github.com/docker/for-linux/issues/264
2) executing out of container :
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# src - https://github.com/angristan/php-xdebug-docker/issues/4#issuecomment-528418403
sudo docker network inspect bridge
find out the “Config > Gateway“ IP 
3) executing out of container :
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ip a
find out the “inet“ for docker0 
4) If you expect that IP address might change you could go the extra mile and do something like :
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docker container run -e "DOCKER_HOST=$(ip -4 addr show docker0 | grep -Po 'inet \K[\d.]+')"
this way every time you run your container, it’ll have the IP address available inside the container set to the DOCKER_HOST environment variable. src
So we know the DockerIP^. Dockerfile part, for Xdebug is :
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# Install xDebug [start]
RUN pecl install xdebug \
&& docker-php-ext-enable xdebug \
&& echo "xdebug.remote_enable=1" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini \
#here replace your DockerIP
&& echo "xdebug.remote_host=172.17.0.1" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
#An IDE key has to be set, but anything works, at least for PhpStorm and VS Code...
ENV XDEBUG_CONFIG="xdebug.idekey=''"
# Install xDebug [end]
At Docker, in a general routine, the mandatory file is the Dockerfile and nothing else, meaning that all various commands using others in a docker-compose.yml file, can be done through commandline. If finally we have a docker-compose.yml file, we proceed with the image build & run, by executing :
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sudo docker-compose up --build -d
Now all setted.
Setup php.ini for Xdebug
inside container, we have to add the following lines at php.ini
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[XDebug]
xdebug.remote_enable = 1
xdebug.remote_autostart = 1
the common path for php.ini is at /usr/local/etc/php, when doesnt exist, locate it using one of the following :
-do a phpinfo() and check the ‘Configuration File (php.ini) Path’ -outside docker exec ‘sudo docker inspect laravel-phpx’ to find the PHP_INI_DIR environment variable (Config > Env > PHP_INI_DIR)
Steps might we take, when no docker-compose.yml file is present.
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# install dependencies - https://hub.docker.com/_/composer
sudo docker run --rm -v $(pwd):/app composer install
# create network - https://docs.docker.com/engine/reference/commandline/network_create/
sudo docker network create --driver bridge laravelX
# build the image - https://docs.docker.com/engine/reference/commandline/build/
sudo docker build -t laravel-php-imgx -f Dockerfile .
# run the image - https://docs.docker.com/v17.12/engine/reference/commandline/run/
sudo docker run --name laravel-phpx --network laravelX -p 8080:80 -v $PWD:/var/www/html laravel-php-imgx
# if you want also mysql run on the same 'network‘ (new container will be created) :
sudo docker run --name laravel-dbX --network laravelX -p 3306:3306 -e MYSQL_ROOT_PASSWORD=root -d mysql:5.7
ref (mysql:5.7) - https://hub.docker.com/_/mysql?tab=tags
after all, make sure is up and running by exec ‘list containers’ command. Various commands :
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# list containers
sudo docker ps -a
# delete the container
sudo docker rm --force laravel-phpx
# list bridges
sudo docker network ls
# get in container
sudo docker exec -it laravel-phpx bash
# remove container (force)
sudo docker rm -f laravel-phpx
# start docker service
sudo service docker start
# start a container
sudo docker start laravel-phpx
# inspect properties
sudo docker inspect laravel-phpx
When container is up and running, make a test php file to see if Xdebug module is there.
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phpinfo();
alternatively :
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# src - https://gist.github.com/joseluisq/d7586c9e5bd52012e0cf
php -r 'echo (extension_loaded("xdebug") ? "xdebug up and running!" : "xdebug is not loaded!");'
At Visual Studio Code (VSCode), add this addon https://marketplace.visualstudio.com/items?itemName=felixfbecker.php-debug
make sure the addon configuration (launch.json) is setted as (the port doesnt matter, if shows that is in use, use 9001 and so on), the various line here is the pathMappings) :
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{
"version": "0.2.0",
"configurations": [
{
"name": "Listen for XDebug",
"type": "php",
"request": "launch",
"port": 9000,
"pathMappings": {
"/var/www/html/": "${workspaceFolder}"
},
}
]
}
XDebug - Debug context lost on multiple connections try to clear @ IDE the watch variable(s) first and restart container and try again!
–
Laravel & Xdebug by Jonathan
By default Laravel will encrypt, and subsequently also decrypt, all cookies on a request.
When using Xdebug to debug your application from a browser, a cookie called “XDEBUG_SESSION” is set. As this cookie was not set, and thus not encrypted, by the Laravel framework, an error will be thrown when the framework automatically detects and tries to decrypt the cookie.
merge this to xdebug addon configuration (launch.json)
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,
"ignore": [
"**/vendor/**/*.php"
]
src - https://stackoverflow.com/a/55340395/1320686
On Fedora, the docker images exist at : /var/lib/docker/overlay2 more
refs : https://xdebug.org/docs/all_settings
Docker for Beginners: Full Course (video)
2017 - After moving from linux to macOS I bumped into looping back to host issue
#docker
origin - https://www.pipiscrew.com/?p=16420 setup-xdebug-in-docker-container-on-linux