This library provides the proxyproto package which can be used for servers
listening behind HAProxy of Amazon ELB load balancers. Those load balancers
support the use of a proxy protocol (http://haproxy.1wt.eu/download/1.5/doc/proxy-protocol.txt),
which provides a simple mechansim for the server to get the address of the client
instead of the load balancer.
This library provides both a net.Listener and net.Conn implementation that can be used to handle situation in which you may be using the proxy protocol. Only proxy protocol version 1, the human-readable form, is understood.
The only caveat is that we check for the "PROXY " prefix to determine if the protocol is being used. If that string may occur as part of your input, then it is ambiguous if the protocol is being used and you may have problems.
Full documentation can be found here.
Using the library is very simple:
// Create a listener
list, err := net.Listen("tcp", "...")
// Wrap listener in a proxyproto listener
proxyList := &proxyproto.Listener{list}
conn, err :=proxyList.Accept()
...