FROM php:8.0-fpm-alpine

# install dependencies
RUN set -ex; \
    apk add --no-cache --virtual \
    .build-deps \
    $PHPIZE_DEPS \
    bash

# use the mlocati/docker-php-extension-installer to install necessary packages and php extensions
# the installer cleans up all dev packages which were only used for compiling
COPY --from=mlocati/php-extension-installer /usr/bin/install-php-extensions /usr/local/bin/
RUN chmod uga+x /usr/local/bin/install-php-extensions && \
    sync && \
    install-php-extensions \
    xdebug

# install composer (needed for PHPUnit updates)
RUN set -ex; \
    curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer

# modify xdebug.ini to reflect php version (replaced by the 'docker-php-ext-enable imagick' command, but still
# a pretty nice command to my mind)
COPY xdebug.ini /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
RUN set -ex; \
    find /usr/local/lib/php/extensions -name "no-debug-non-zts-*" | \
    xargs basename | \
    xargs -I '{}' sed -i 's/{folder_version}/{}/g' /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini

VOLUME /var/www/html
WORKDIR /var/www/html

CMD php-fpm

Version => 3.0.1
Support Xdebug on Patreon, GitHub, or as a business: https://xdebug.org/support

Directive => Local Value => Master Value
xdebug.auto_trace => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.auto_trace" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.auto_trace"
xdebug.collect_includes => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_includes" => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_includes"
xdebug.collect_params => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_params" => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_params"

...

[xdebug]
; enable the extension
zend_extension=/usr/local/lib/php/extensions/{folder_version}/xdebug.so

; do NOT use the incoming IP address to connect back
xdebug.remote_connect_back=0
; use DNS entry to resolve the host instead
; @see https://docs.docker.com/docker-for-windows/networking/#i-cannot-ping-my-containers
xdebug.remote_host=10.254.254.254
; use port 9000 on the remote host for connection
xdebug.remote_port=9002
; enable debugging
xdebug.default_enable=0
xdebug.remote_enable=1
xdebug.remote_autostart=0
xdebug.idekey=PHPSTORM

; save detailed information in a log file
; only required when setting up xdebug
xdebug.remote_log="/tmp/xdebug.log"