Add a new protocol

Co-authored-by: Gérald Croës <gerald@containo.us>

tcp/rr_load_balancer.go

@@ -0,0 +1,44 @@
+package tcp
+
+import (
+	"net"
+	"sync"
+
+	"github.com/containous/traefik/log"
+)
+
+// RRLoadBalancer is a naive RoundRobin load balancer for TCP services
+type RRLoadBalancer struct {
+	servers []Handler
+	lock    sync.RWMutex
+	current int
+}
+
+// NewRRLoadBalancer creates a new RRLoadBalancer
+func NewRRLoadBalancer() *RRLoadBalancer {
+	return &RRLoadBalancer{}
+}
+
+// ServeTCP forwards the connection to the right service
+func (r *RRLoadBalancer) ServeTCP(conn net.Conn) {
+	r.next().ServeTCP(conn)
+}
+
+// AddServer appends a server to the existing list
+func (r *RRLoadBalancer) AddServer(server Handler) {
+	r.servers = append(r.servers, server)
+}
+
+func (r *RRLoadBalancer) next() Handler {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+
+	// FIXME handle weight
+	if r.current >= len(r.servers) {
+		r.current = 0
+		log.Debugf("Load balancer: going back to the first available server")
+	}
+	handler := r.servers[r.current]
+	r.current++
+	return handler
+}