Disable IPv6 in Nginx if unsupported

Relates to #73

files/40-disable-nginx-ipv6-if-unsupported.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+# Based on /etc/docker-entrypoint.d/10-listen-on-ipv6-by-default.sh, since the
+# same one cannot be used because the checksum of the default.conf differs.
+
+set -e
+ME=$(basename $0)
+
+# Disable IPv6 configuration if not supported or nginx is not installed
+# Added to resolve https://github.com/ckulka/baikal-docker/issues/73
+if nginx -t 2>&1 >/dev/null | grep -q '\[emerg\] socket() \[::\]:80 failed (97: Address family not supported by protocol)'; then
+    echo >&3 "$ME: info: Disable IPv6 in configuration"
+    sed -i 's/listen \[::\]:80;/# listen \[::\]:80/' /etc/nginx/conf.d/default.conf
+fi