corelight/json-tcp-lb repository overview

⁠json tcp lb

This is a simple line based tcp load balancing proxy. It is designed to work with newline delimited json, but will work with any line based protocol.

This is different from a basic TCP proxy in that it will load balance data in a single connection across multiple destinations.

⁠Features

• Load balancing to multiple connections across multiple targets.
• Failed transmissions will be retried to avoid ever losing data.
• Target failover and failback.

⁠Implementation

• The proxy will start up N worker connections to each target.
• The proxy will read data from the incoming connection into a 16KB buffer.
• The buffer will be split cleanly on a newline boundary, or combined with additional data until at least one newline is seen.
• The buffer containing one or more lines is places onto a channel and will be pulled by a worker and transmitted to a target.
• If any of the worker connections fail, it will attempt to connect to a random target instead.
• Every 5 minutes it will attempt to reconnect to its original target.

⁠Usage

Usage of ./json-tcp-lb:
  -addr string
        Address to listen on (default "0.0.0.0")
  -port int
        Port to listen on (default 9000)
  -target string
        Address to proxy to. separate multiple with comma (default "127.0.0.1:9999")
  -connections int
        Number of outbound connections to make to each target (default 4)

⁠Container Usage

The Dockerfile can be used to build the tcp lb in a container, then run like the following example:

docker build -t json-tcp-lb .
docker run -p ${LISTEN_PORT}:${LISTEN_PORT} -target ${TARGET_STRING} json-tcp-lb

⁠Alternatives

I'm not aware of any simple alternatives. This is similar to something like gRPC load balancing across a single http/2 session in something like Envoy. It's likely possible to add 'newline delimited' data as a codec in Envoy or another load balancer.