feat(gl): add standalone ledger authority mode

cmd/healthcheck/main.go

@@ -3,15 +3,22 @@ package main
 import (
 	"context"
 	"flag"
+	"net"
 	"os"
+	"strconv"
 	"time"
 
+	basev1 "gl/gen/base/v1"
+	ledgerv1 "gl/gen/ledger/v1"
 	"gl/infrastructure/config"
 	"gl/infrastructure/postgres"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
 )
 
 func main() {
 	configPath := flag.String("conf", "/app/config.toml", "path to the GL TOML configuration file")
+	grpcProbe := flag.Bool("grpc", false, "check the serving GL API instead of only its database")
 	flag.Parse()
 	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 	defer cancel()
@@ -19,6 +26,23 @@ func main() {
 	if err != nil {
 		os.Exit(1)
 	}
+
+	if *grpcProbe {
+		host := cfg.GRPC.Host
+		if host == "0.0.0.0" || host == "::" {
+			host = "127.0.0.1"
+		}
+		connection, err := grpc.NewClient(net.JoinHostPort(host, strconv.Itoa(cfg.GRPC.Port)), grpc.WithTransportCredentials(insecure.NewCredentials()))
+		if err != nil {
+			os.Exit(1)
+		}
+		defer connection.Close()
+		health, err := ledgerv1.NewGeneralLedgerServiceClient(connection).Health(ctx, &basev1.Empty{})
+		if err != nil || !health.GetServing() || !health.GetDatabaseReady() {
+			os.Exit(1)
+		}
+		return
+	}
 	database, err := postgres.Open(ctx, cfg.Database)
 	if err != nil {
 		os.Exit(1)