Connect to a gRPC server with TLS (without a certificate, key pair)

Dockerfile

FROM golang:alpine AS builder
RUN apk --no-cache add build-base git mercurial gcc
ADD . /go/src/grpc-client-test
RUN cd /go/src/grpc-client-test && go build -o grpc-client-test main.go

FROM alpine
COPY --from=builder /go/src/grpc-client-test /grpc-client-test

ENV GRPC_GO_LOG_SEVERITY_LEVEL=info
ENV GRPC_GO_LOG_VERBOSITY_LEVEL=6

ENTRYPOINT ["/grpc-client-test"]

main.go

package main

import (
	"context"
	"crypto/tls"
	"fmt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"google.golang.org/grpc/health/grpc_health_v1"
	"os"
	"path"
	"time"
)

func main() {
	prog := path.Base(os.Args[0])

	if len(os.Args) < 2 {
		_, _ = fmt.Fprintf(os.Stderr, "usage: %s HOST:PORT\n", prog)
		os.Exit(1)
	}

	addr := os.Args[1]
	creds := credentials.NewTLS(&tls.Config{InsecureSkipVerify: false})

	ctx, _ := context.WithTimeout(context.Background(), 5*time.Second)
	conn, err := grpc.DialContext(ctx, addr, grpc.WithTransportCredentials(creds))

	if err != nil {
		_, _ = fmt.Fprintf(os.Stderr, "%s: %s\n", prog, err)
		os.Exit(1)
	}

	defer conn.Close()

	client := grpc_health_v1.NewHealthClient(conn)

	rsp, err := client.Check(context.Background(), &grpc_health_v1.HealthCheckRequest{})

	if err != nil {
		_, _ = fmt.Fprintf(os.Stderr, "%s: %s\n", prog, err)
		os.Exit(1)
	}

	fmt.Printf("Status: %s\n", rsp.Status)
}