disable IPv6 via env

Author: moonbuggy

README.md

@@ -102,6 +102,7 @@ ENV PROXY_REQUEST_BUFFERING="true"
   - PROXY_CONNECT_READ_TIMEOUT : see [proxy_connect_read_timeout](https://github.com/chobits/ngx_http_proxy_connect_module#proxy_connect_read_timeout)
   - PROXY_CONNECT_CONNECT_TIMEOUT : see [proxy_connect_connect_timeout](https://github.com/chobits/ngx_http_proxy_connect_module#proxy_connect_connect_timeout)
   - PROXY_CONNECT_SEND_TIMEOUT : see [proxy_connect_send_timeout](https://github.com/chobits/ngx_http_proxy_connect_module#proxy_connect_send_timeout)
+- Env `DISABLE_IPV6`: If set to `true`, prevents nginx from getting IPv6 addresses from the resolver without needing a [custom resolver config](#custom_nginx_resolvers_configuration)
 
 
 ### Simple (no auth, all cache)

entrypoint.sh

@@ -33,6 +33,10 @@ confpath=/etc/nginx/resolvers.conf
 if [ ! -e $confpath ]
 then
     echo "Using auto-determined resolver '$conf' via '$confpath'"
+    if [[ "a${DISABLE_IPV6}" == "atrue" ]]; then
+      echo "Disabling IPv6 in '$confpath'"
+      conf="${conf%;*} ipv6=off;"
+    fi
     echo "$conf" > $confpath
 else
     echo "Not using resolver config, keep existing '$confpath' -- mounted by user?"