Add initial "NGINX Unit" based image

The Unit configuration I've included here is based on the example provided by the Unit documentation (https://unit.nginx.org/howto/wordpress/), although I did spend time understanding it before blindly trusting it. 😄

The biggest 😬 here (IMO) is that WordPress itself does not know about Unit yet, so the permalink handling is a bit off -- I've added a hack in `wp-config-docker.php` (specifically in the Unit images only) which works around it by teaching WordPress that Unit is effectively NGINX (which does work and is accurate enough for what WordPress needs), but that should probably be an issue or PR to the WordPress community instead.

Dockerfile.template

@@ -2,7 +2,11 @@
 	def is_alpine:
 		env.variant | index("alpine")
 -}}
+{{ if env.variant == "unit" then ( -}}
+FROM unit:{{ .unit.version }}-php{{ env.phpVersion }}
+{{ ) else ( -}}
 FROM php:{{ env.phpVersion }}-{{ env.variant }}
+{{ ) end -}}
 
 {{ if env.version != "cli" then ( -}}
 # persistent dependencies
@@ -252,12 +256,38 @@ VOLUME /var/www/html
 
 {{ if env.version != "cli" then ( -}}
 COPY --chown=www-data:www-data wp-config-docker.php /usr/src/wordpress/
+{{ if env.variant == "unit" then ( -}}
+
+# NGINX Unit specific bits
+WORKDIR /var/www/html
+RUN set -eux; \
+# save Unit's entrypoint so we can successfully/correctly configure Unit at runtime
+	sed -e 's/docker-entrypoint/unit-entrypoint/g' /usr/local/bin/docker-entrypoint.sh > /usr/local/bin/unit-entrypoint.sh; \
+	grep -F '/unit-entrypoint.d/' /usr/local/bin/unit-entrypoint.sh; \
+	chmod +x /usr/local/bin/unit-entrypoint.sh; \
+	\
+	{ \
+		echo; \
+		echo '// WordPress does not support NGINX Unit (yet), so we have to do a little hackery to let it know that Unit supports nice permalinks (and prevent it from insisting on injecting "/index.php" in all the permalink options) -- the simplest way is teaching it to recognize Unit as if it were NGINX (which is only semi-true, but true enough for these purposes)'; \
+		echo '$is_nginx = $is_nginx || str_starts_with($_SERVER["SERVER_SOFTWARE"], "Unit/");'; \
+		echo '// see also https://github.com/WordPress/WordPress/blob/39f7f558d91afdd2f3afc7f3b049a6a800cd3f80/wp-includes/vars.php#L127'; \
+	} >> /usr/src/wordpress/wp-config-docker.php
+COPY unit.json /unit-entrypoint.d/wordpress.json
+
+{{ ) else "" end -}}
 {{ ) else "" end -}}
 COPY docker-entrypoint.sh /usr/local/bin/
 
 ENTRYPOINT ["docker-entrypoint.sh"]
 {{ if env.version != "cli" then ( -}}
-CMD {{ [ if env.variant == "apache" then "apache2-foreground" else "php-fpm" end ] | @json }}
+CMD {{
+	{
+		apache: [ "apache2-foreground" ],
+		# https://github.com/nginx/unit/blob/fb33ec86a3b6ca6a844dfa6980bb9e083094abec/pkg/docker/Dockerfile.php8.2#L89
+		unit: [ "unitd", "--no-daemon", "--control", "unix:/var/run/control.unit.sock" ],
+	}[env.variant] // [ "php-fpm" ]
+	| @json
+}}
 {{ ) else ( -}}
 USER www-data
 CMD ["wp", "shell"]

apply-templates.sh

@@ -43,6 +43,10 @@ for version; do
 		for variant in "${variants[@]}"; do
 			export variant
 
+			if [ "$variant" = 'unit' ] && jq -e '.[env.version][env.variant].phpVersions | index(env.phpVersion) | not' versions.json > /dev/null; then
+				continue
+			fi
+
 			dir="$version/php$phpVersion/$variant"
 			mkdir -p "$dir"
 
@@ -58,6 +62,10 @@ for version; do
 			else
 				cp -a docker-entrypoint.sh wp-config-docker.php "$dir/"
 			fi
+
+			if [ "$variant" = 'unit' ]; then
+				cp -a unit.json "$dir/"
+			fi
 		done
 	done
 done