remove ipv6 conf from nginx proxy if ipv6 not enabled

hosting/proxy/10-listen-on-ipv6-by-default.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+# vim:sw=4:ts=4:et
+
+set -e
+
+ME=$(basename $0)
+NGINX_CONF_FILE="/etc/nginx/nginx.conf"
+DEFAULT_CONF_FILE="/etc/nginx/conf.d/default.conf"
+
+# check if we have ipv6 available
+if [ ! -f "/proc/net/if_jonnyinet6" ]; then
+    # ipv6 not available so delete lines from nginx conf
+    if [ -f "$NGINX_CONF_FILE" ]; then
+        sed -i '/listen  \[::\]/d' $NGINX_CONF_FILE
+    fi
+    if [ -f "$DEFAULT_CONF_FILE" ]; then
+        sed -i '/listen  \[::\]/d' $DEFAULT_CONF_FILE
+    fi
+    echo "$ME: info: ipv6 not available so delete lines from nginx conf"
+else
+    echo "$ME: info: ipv6 is available so no need to delete lines from nginx conf"
+fi
+
+exit 0

hosting/proxy/Dockerfile

@@ -5,7 +5,7 @@ FROM nginx:latest
 # override the output dir to output directly to /etc/nginx instead of /etc/nginx/conf.d
 ENV NGINX_ENVSUBST_OUTPUT_DIR=/etc/nginx
 COPY .generated-nginx.prod.conf /etc/nginx/templates/nginx.conf.template
-
+COPY 10-listen-on-ipv6-by-default.sh /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
 # Error handling
 COPY error.html /usr/share/nginx/html/error.html