docker: Add script for selecting different PHP versions

`jetpack docker select-php` (or `select-php` inside the container) is
now avalable to install and run a different version of PHP inside the
container.

tools/cli/commands/docker.js

@@ -328,6 +328,8 @@ const buildExecCmd = argv => {
 		opts.push( 'bash' );
 	} else if ( cmd === 'db' ) {
 		opts.push( 'mysql', '--defaults-group-suffix=docker' );
+	} else if ( cmd === 'select-php' ) {
+		opts.push( 'select-php', argv.version );
 	} else if ( cmd === 'phpunit' ) {
 		// @todo: Make this scale.
 		console.warn( chalk.yellow( 'This currently only run tests for the Jetpack plugin.' ) );
@@ -624,6 +626,18 @@ export function dockerDefine( yargs ) {
 					builder: yargExec => defaultOpts( yargExec ),
 					handler: argv => execDockerCmdHandler( argv ),
 				} )
+				.command( {
+					command: 'select-php <version>',
+					description:
+						'Select the version of PHP for use inside the container. See documentation for important notes!',
+					builder: yargCmd => {
+						yargCmd.positional( 'version', {
+							describe: 'The version to select, or "default".',
+							type: 'string',
+						} );
+					},
+					handler: argv => execDockerCmdHandler( argv ),
+				} )
 				.command( {
 					command: 'phpunit',
 					description: 'Run PHPUnit tests inside container',

tools/docker/Dockerfile

@@ -12,6 +12,13 @@ ENV LC_ALL en_US.UTF-8
 
 WORKDIR /tmp
 
+# Record ARGs
+RUN \
+	echo "PHP_VERSION=$PHP_VERSION" > /etc/docker-args.sh \
+	&& echo "NODE_VERSION=$NODE_VERSION" >> /etc/docker-args.sh \
+	&& echo "COMPOSER_VERSION=$COMPOSER_VERSION" >> /etc/docker-args.sh \
+	&& echo "PNPM_VERSION=$PNPM_VERSION" >> /etc/docker-args.sh
+
 # Install basic packages, including Apache.
 RUN --mount=type=cache,target=/var/lib/apt/lists/,sharing=private \
 	export DEBIAN_FRONTEND=noninteractive \
@@ -41,31 +48,12 @@ RUN --mount=type=cache,target=/var/lib/apt/lists/,sharing=private \
 RUN a2enmod rewrite
 
 # Install requested version of PHP.
+COPY ./bin/select-php.sh /usr/local/bin/select-php
+RUN chmod +x /usr/local/bin/select-php
+COPY ./config/php.ini /var/lib/jetpack-config/php.ini
 RUN --mount=type=cache,target=/var/lib/apt/lists/,sharing=private \
 	: "${PHP_VERSION:?Build argument PHP_VERSION needs to be set and non-empty.}" \
-	&& export DEBIAN_FRONTEND=noninteractive \
-	&& apt-get install -y \
-		libapache2-mod-php${PHP_VERSION} \
-		php${PHP_VERSION} \
-		php${PHP_VERSION}-bcmath \
-		php${PHP_VERSION}-cli \
-		php${PHP_VERSION}-curl \
-		php${PHP_VERSION}-intl \
-		php${PHP_VERSION}-ldap \
-		php${PHP_VERSION}-mbstring \
-		php${PHP_VERSION}-mysql \
-		php${PHP_VERSION}-opcache \
-		php${PHP_VERSION}-pgsql \
-		php${PHP_VERSION}-soap \
-		php${PHP_VERSION}-sqlite3 \
-		php${PHP_VERSION}-xdebug \
-		php${PHP_VERSION}-xml \
-		php${PHP_VERSION}-xsl \
-		php${PHP_VERSION}-zip \
-	&& apt-get install -y --no-install-recommends \
-		php${PHP_VERSION}-apcu \
-		php${PHP_VERSION}-gd \
-		php${PHP_VERSION}-imagick \
+	&& /usr/local/bin/select-php "$PHP_VERSION" \
 	&& find /var/ -name '*-old' -delete && rm -rf /var/log/dpkg.log /var/log/alternatives.log /var/log/apt/ ~/.launchpadlib
 
 # Install requested version of Composer.
@@ -109,10 +97,6 @@ RUN mkdir /usr/local/src/psysh \
 # Copy a default config file for an apache host.
 COPY ./config/apache_default /etc/apache2/sites-available/000-default.conf
 
-# Copy a default set of settings for PHP (php.ini).
-COPY ./config/php.ini /etc/php/${PHP_VERSION}/mods-available/jetpack-wordpress.ini
-RUN phpenmod jetpack-wordpress
-
 # Copy single site htaccess to /var/lib/jetpack-config. run.sh will move it to the site's base dir if there's none present.
 COPY ./config/htaccess /var/lib/jetpack-config/htaccess
 COPY ./config/htaccess-multi /var/lib/jetpack-config/htaccess-multi

tools/docker/README.md

@@ -212,6 +212,25 @@ wp> get_bloginfo( 'name' );
 
 Note that each `wp shell` session counts as a single request, causing unexpected situations with WP cache. You might want to run [`wp_cache_flush()`](https://developer.wordpress.org/reference/functions/wp_cache_flush/) between requests you expect to get cached by WordPress.
 
+### Changing PHP versions
+
+You can select different versions of PHP. For example, to use PHP 8.0 inside the container:
+
+```sh
+jetpack docker select-php 8.0
+```
+
+If you're already inside the container after using `jetpack docker sh`, you can use `select-php 8.0` there too.
+
+Note some caveats:
+
+* Running `jetpack docker down` or otherwise recreating the containers will reset to the default PHP version.
+* If you're wanting the new version of PHP to be used to serve web requests, you'll need to `jetpack docker stop && jetpack docker up -d` or the like.
+* You may need to update Composer packages from inside the container before you can successfully run `phpunit` or the like, in order to install a version compatible with the new version of PHP.
+  * For example, `jetpack docker exec -- composer -d /usr/local/src/jetpack-monorepo/projects/plugins/jetpack update`
+  * Be careful not to commit any resulting changes to `composer.lock` files!
+  * On Linux systems, doing this may result in odd ownership of files in relevant `vendor/` and `jetpack_vendor/` directories. Removing them (probaby using `sudo`) is a valid fix.
+
 ## MySQL database
 
 You can see your database files via local file system at `./tools/docker/data/mysql`

tools/docker/bin/select-php.sh

@@ -0,0 +1,93 @@
+#!/bin/bash
+
+set -eo pipefail
+
+source /etc/docker-args.sh
+
+VER=$1
+if [[ "$1" == default ]]; then
+	VER="$PHP_VERSION"
+elif [[ ! "$1" =~ ^[0-9]+\.[0-9]+$ ]]; then
+	cat <<-EOF
+		USAGE: $0 <version>
+
+		<version> may be "default" or a two-part version number like "$PHP_VERSION".
+	EOF
+	exit 1
+fi
+
+export DEBIAN_FRONTEND=noninteractive
+
+# Determine packages to install.
+PKGS=(
+	"libapache2-mod-php${VER}"
+	"php${VER}"
+	"php${VER}-bcmath"
+	"php${VER}-cli"
+	"php${VER}-curl"
+	"php${VER}-intl"
+	"php${VER}-ldap"
+	"php${VER}-mbstring"
+	"php${VER}-mysql"
+	"php${VER}-opcache"
+	"php${VER}-pgsql"
+	"php${VER}-soap"
+	"php${VER}-sqlite3"
+	"php${VER}-xdebug"
+	"php${VER}-xml"
+	"php${VER}-xsl"
+	"php${VER}-zip"
+)
+NO_RECOMMENDS_PKGS=(
+	"php${VER}-apcu"
+	"php${VER}-gd"
+	"php${VER}-imagick"
+)
+
+# php-json is built in in 8.0+.
+if [[ "$VER" == [57].* ]]; then
+	PKGS+=( "php${VER}-json" )
+fi
+
+# Install selected packages.
+printf '\e[1m== Installing PHP %s ==\e[0m\n' "$VER"
+apt-get update -q
+apt-get install -qy "${PKGS[@]}"
+apt-get install -qy --no-install-recommends "${NO_RECOMMENDS_PKGS[@]}"
+
+# Enable our custom config for the new version.
+[[ -e "/etc/php/${VER}/mods-available/jetpack-wordpress.ini" ]] || ln -s /var/lib/jetpack-config/php.ini "/etc/php/${VER}/mods-available/jetpack-wordpress.ini"
+phpenmod -v "$VER" jetpack-wordpress
+
+# Upgrade or downgrade Composer if necessary.
+if command -v composer &> /dev/null; then
+	printf '\n\e[1m== Installing Composer ==\e[0m\n'
+	if [[ "$VER" == 5.6 || "$VER" == 7.[01] ]]; then
+		CV=2.2.18
+	else
+		CV="$COMPOSER_VERSION"
+	fi
+	# Execute with whichever version of PHP is newer.
+	if php -r 'exit( version_compare( PHP_VERSION, $argv[1], ">" ) ? 0 : 1 );' "$PHP_VERSION"; then
+		composer self-update "$CV"
+	else
+		"php$VER" "$(command -v composer)" self-update "$CV"
+	fi
+fi
+
+# Select the new version to be used for stuff.
+printf '\n\e[1m== Setting PHP %s as default ==\e[0m\n' "$VER"
+for name in php phar phar.phar; do
+	update-alternatives --quiet --set "$name" "/usr/bin/$name$VER"
+done
+if a2query -m | grep -q "^php$VER "; then
+	:
+else
+	if a2query -m | grep -q '^php'; then
+		a2dismod 'php*'
+	fi
+	a2enmod "php$VER"
+
+	printf '\n\e[30;43mThe web server is still running the old version of PHP!\e[0m\n'
+	printf '\e[30;43mRestart the docker container (e.g. `jetpack docker stop && jetpack docker up -d`) to use the new version.\e[0m\n'
+fi