Use the golang.org/x/net/http2/h2c module

go.mod

@@ -27,6 +27,7 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.28.0
 	go.opentelemetry.io/otel/sdk v1.28.0
 	go.opentelemetry.io/otel/trace v1.28.0
+	golang.org/x/net v0.26.0
 	google.golang.org/grpc v1.65.0
 	google.golang.org/protobuf v1.34.2
 )
@@ -63,7 +64,6 @@ require (
 	go.opentelemetry.io/proto/otlp v1.3.1 // indirect
 	golang.org/x/crypto v0.24.0 // indirect
 	golang.org/x/mod v0.17.0 // indirect
-	golang.org/x/net v0.26.0 // indirect
 	golang.org/x/sync v0.7.0 // indirect
 	golang.org/x/sys v0.21.0 // indirect
 	golang.org/x/text v0.16.0 // indirect

pkg/grpc/grpc.go

@@ -9,6 +9,8 @@ import (
 	"net/http"
 
 	pb "github.com/grafana/quickpizza/pkg/grpc/quickpizza"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
 	"google.golang.org/grpc"
 )
 
@@ -45,13 +47,13 @@ func NewServer(listen string, healthzListen string) *Server {
 
 func (s *Server) listenHealthz() {
 	mux := http.NewServeMux()
-	mux.HandleFunc("/healthz", func(w http.ResponseWriter, req *http.Request) {
+	mux.HandleFunc("/grpchealthz", func(w http.ResponseWriter, req *http.Request) {
 		w.WriteHeader(http.StatusNoContent)
 	})
 
 	health := &http.Server{
 		Addr:    s.healthzListen,
-		Handler: mux,
+		Handler: h2c.NewHandler(mux, &http2.Server{}),
 	}
 
 	slog.Info("Starting QuickPizza gRPC health check server", "listenAddress", s.healthzListen)

vendor/modules.txt

@@ -228,6 +228,7 @@ golang.org/x/mod/semver
 ## explicit; go 1.18
 golang.org/x/net/http/httpguts
 golang.org/x/net/http2
+golang.org/x/net/http2/h2c
 golang.org/x/net/http2/hpack
 golang.org/x/net/idna
 golang.org/x/net/internal/timeseries