package tcp import ( "net" "sync" "github.com/containous/traefik/pkg/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) { if len(r.servers) == 0 { log.WithoutContext().Error("no available server") return } 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() 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 }