Add support for forward input

In order to place the sumologic integration in a broader fluentd
infrastructure, add support the forward protocol, allowing to aggregate
logs from several external sources, send all in one place to sumologic.

Author: tjamet

Dockerfile

@@ -59,6 +59,8 @@ ENV K8S_METADATA_FILTER_VERIFY_SSL "true"
 ENV K8S_METADATA_FILTER_BEARER_CACHE_SIZE "1000"
 ENV K8S_METADATA_FILTER_BEARER_CACHE_TTL "3600"
 ENV VERIFY_SSL "true"
+ENV FORWARD_INPUT_BIND "0.0.0.0"
+ENV FORWARD_INPUT_PORT "24224"
 
 COPY --from=builder /var/lib/gems /var/lib/gems
 

conf.d/forward/placeholder

@@ -4,7 +4,7 @@ if [ $# -gt 0 ] && [ "${1:0:1}" != "-" ]; then
 else
   cd `dirname $0`
 
-  if [ $FLUENTD_SOURCE != file ] && [ $FLUENTD_SOURCE != systemd ]; then
+  if ! ls /fluentd/etc/fluent.${FLUENTD_SOURCE}.conf > /dev/null; then
     echo "Unknown source '$FLUENTD_SOURCE'"
     if [ -e /dev/termination-log ]; then
       echo "Unknown source '$FLUENTD_SOURCE'" >/dev/termination-log

entrypoint.sh

@@ -0,0 +1,18 @@
+## built-in TCP input
+## $ echo <json> | fluent-cat <tag>
+<source>
+  @type forward
+  @id forward_input
+  port "#{ENV['FORWARD_INPUT_PORT']}"
+  bind "#{ENV['FORWARD_INPUT_BIND']}"
+</source>
+
+<source>
+  @type monitor_agent
+  bind 0.0.0.0
+  port 24220
+</source>
+
+@include /fluentd/conf.d/forward/source.*.conf
+@include /fluentd/conf.d/user/*.conf
+@include /fluentd/conf.d/out.sumo.conf