A sample program to connect to a headscale server over gRPC

headscale_grpc_client.go

// A sample program that connects to the headscale gRPC server
// and lists all the API keys
//
// Usage Example: go run main.go -server=localhost:50443 -apikey=3GbSjH5IqA.1FPG5ZiqB3a8idtvJnhBjCSb_V5pffuaLyFJyYZNPlQ

package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/signal"

	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
)

var (
	HeadscaleServer string
	ApiKey          string
)

func main() {
	flag.StringVar(&HeadscaleServer, "server", "", "<headscale-grpc-endpoint:port>")
	flag.StringVar(&ApiKey, "apikey", "", "")
	flag.Parse()

	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, os.Kill)
	defer cancel()

	client, err := getHeadscaleClient(ctx, HeadscaleServer, ApiKey)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	res, err := client.ListApiKeys(ctx, &v1.ListApiKeysRequest{})
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	fmt.Println(res)
}

type tokenAuth struct {
	token string
}

// Return value is mapped to request headers.
func (t tokenAuth) GetRequestMetadata(
	ctx context.Context,
	in ...string,
) (map[string]string, error) {
	return map[string]string{
		"authorization": "Bearer " + t.token,
	}, nil
}

func (tokenAuth) RequireTransportSecurity() bool { return false }

func getHeadscaleClient(
	ctx context.Context, server,
	apiKey string,
) (v1.HeadscaleServiceClient, error) {
	grpcOptions := []grpc.DialOption{
		grpc.WithBlock(),
		grpc.WithPerRPCCredentials(tokenAuth{
			token: ApiKey,
		}),
		grpc.WithTransportCredentials(insecure.NewCredentials()),
	}

	conn, err := grpc.DialContext(ctx, HeadscaleServer, grpcOptions...)
	if err != nil {
		return nil, err
	}

	client := v1.NewHeadscaleServiceClient(conn)

	return client, nil
}