gRPC Load Balancing in Go

Go does not have a built-in gRPC load balancer; you must configure one in your http.Transport or use an external service like Envoy. For client-side round-robin or least-request balancing, set the Dial function in your http.Transport to connect to a list of backend addresses and cycle through them manually, or use the golang.org/x/net/http2 package with a custom DialTLS implementation that selects the next available server.

import (
	"context"
	"crypto/tls"
	"net"
	"net/http"
	"sync/atomic"
	"time"
)

var serverIndex uint64
var servers = []string{"addr1:50051", "addr2:50051", "addr3:50051"}

func dialFunc(ctx context.Context, network, addr string) (net.Conn, error) {
	idx := atomic.AddUint64(&serverIndex, 1) % uint64(len(servers))
	return net.DialTimeout(network, servers[idx], 5*time.Second)
}

func main() {
	tr := &http.Transport{
		DialContext: dialFunc,
		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
	}
	client := &http.Client{Transport: tr}
	// Use client for gRPC over HTTP/2 requests
}

Go's standard library doesn't automatically split traffic across multiple gRPC servers. You need to write a small piece of code that picks a server address from a list every time a new connection is made, similar to a traffic cop directing cars to different lanes to prevent congestion.