Simplify handling of `XDEBUG_CLIENT_HOST`

[homersimpsons]

Previously, we had to manually fetch the host ip from the container. This is rather hacky, and this starts failing for me locally. We should instead default to xdebug://gateway, https://xdebug.org/docs/step_debug#client_host:

xdebug://gateway

Use the system defined network gateway.

Supported on Linux only.

References:

docker-images-php/utils/docker-entrypoint-as-root.sh

Lines 84 to 114 in 355c1ac

	if [ -z "$XDEBUG_CLIENT_HOST" ]; then
	export XDEBUG_CLIENT_HOST=`/sbin/ip route|awk '/default/ { print $3 }'`
	set +e
	# On Windows and MacOS with Docker >= 18.03, check that host.docker.internal exists. it true, use this.
	# Linux systems can report the value exists, but it is bound to localhost. In this case, ignore.
	host -t A host.docker.internal &> /dev/null
	if [[ $? == 0 ]]; then
	# The host exists.
	DOCKER_HOST_INTERNAL=`host -t A host.docker.internal | awk '/has address/ { print $4 }'`
	if [ "$DOCKER_HOST_INTERNAL" != "127.0.0.1" ]; then
	export XDEBUG_CLIENT_HOST=$DOCKER_HOST_INTERNAL
	export REMOTE_HOST_FOUND=1
	fi
	fi
	if [[ "$REMOTE_HOST_FOUND" != "1" ]]; then
	# On mac with Docker < 18.03, check that docker.for.mac.localhost exists. it true, use this.
	# Linux systems can report the value exists, but it is bound to localhost. In this case, ignore.
	host -t A docker.for.mac.localhost &> /dev/null
	if [[ $? == 0 ]]; then
	# The host exists.
	DOCKER_FOR_MAC_REMOTE_HOST=`host -t A docker.for.mac.localhost | awk '/has address/ { print $4 }'`
	if [ "$DOCKER_FOR_MAC_REMOTE_HOST" != "127.0.0.1" ]; then
	export XDEBUG_CLIENT_HOST=$DOCKER_FOR_MAC_REMOTE_HOST
	fi
	fi
	fi
	set -e
	fi

docker-images-php/README.md

Line 330 in 355c1ac

If you enable XDebug, the image will do its best to configure the `xdebug.client_host` to point back to your Docker host.

docker-images-php/utils/README.blueprint.md

Line 278 in 355c1ac

If you enable XDebug, the image will do its best to configure the `xdebug.client_host` to point back to your Docker host.

Maybe we should adapt the test too

docker-images-php/tests-suite/php-xdebug.sh

Lines 1 to 23 in 355c1ac

	#!/usr/bin/env bash
	. ./config
	############################################################
	## xdebug
	############################################################
	test_config() {
	# Let's check that the "xdebug.client_host" contains a value different from "no value"
	docker run ${RUN_OPTIONS} --rm -e PHP_EXTENSION_XDEBUG=1 "${REPO}:${TAG_PREFIX}${PHP_VERSION}-${BRANCH}-${BRANCH_VARIANT}" \
	php -i | grep xdebug.client_host | grep -v -q "no value"
	assert_equals "0" "$?" '"xdebug.client_host" contains "no value"'
	# Let's check that "xdebug.mode" is set to "debug" by default
	docker run ${RUN_OPTIONS} --rm -e PHP_EXTENSION_XDEBUG=1 "${REPO}:${TAG_PREFIX}${PHP_VERSION}-${BRANCH}-${BRANCH_VARIANT}" \
	php -i | grep xdebug.mode | grep -q "debug"
	assert_equals "0" "$?" '"xdebug.mode" is not set to "debug" by default'
	# Let's check that "xdebug.mode" is properly overridden
	docker run ${RUN_OPTIONS} --rm -e PHP_EXTENSION_XDEBUG=1 -e PHP_INI_XDEBUG__MODE=debug,coverage \
	"${REPO}:${TAG_PREFIX}${PHP_VERSION}-${BRANCH}-${BRANCH_VARIANT}" \
	php -i | grep xdebug.mode | grep -q "debug,coverage"
	assert_equals "0" "$?" '"xdebug.mode" is not properly overridden'
	}