Speed up page rendering

Roughly doubles the speed when serving from warm caches.

.gitmodules

@@ -31,3 +31,6 @@
 [submodule "src/extensions/Nuke"]
 	path = src/extensions/Nuke
 	url = git@github.com:wikimedia/mediawiki-extensions-Nuke.git
+[submodule "ext/luasandbox"]
+	path = ext/luasandbox
+	url = https://gerrit.wikimedia.org/r/mediawiki/php/luasandbox.git

Dockerfile

@@ -65,6 +65,18 @@ RUN composer install --no-dev --working-dir=/var/www/html/w/extensions/CheckUser
 RUN composer install --no-dev --working-dir=/var/www/html/w/extensions/Echo
 RUN composer install --no-dev --working-dir=/var/www/html/w/extensions/Flow
 
+# Better Scribunto (lua) performance, apparently
+COPY ext/luasandbox /opt/luasandbox
+RUN apt-get update && apt-get install -y liblua5.1-0-dev
+RUN ( \
+    cd /opt/luasandbox; \
+    phpize; \
+    ./configure; \
+    make; \
+    make install \
+)
+RUN docker-php-ext-enable luasandbox
+
 # Generate config at runtime
 COPY scripts/configure-mediawiki.sh /usr/local/bin/configure-mediawiki
 COPY scripts/configure-blackfire.sh /usr/local/bin/configure-blackfire

configs/LocalSettings.php

@@ -388,7 +388,7 @@
 
 # Scribunto extension for running lua code on wiki -- Moussekateer 16/11/13
 wfLoadExtension( 'Scribunto' );
-$wgScribuntoDefaultEngine = 'luastandalone';
+$wgScribuntoDefaultEngine = 'luasandbox';
 
 # CodeEditor extension for more featured editor for code pages -- Moussekateer 16/11/13
 wfLoadExtension( 'CodeEditor' );