refactor(agent): error handling

agent/main.go

@@ -97,37 +97,31 @@ func main() {
 
 	wg := &errgroup.Group{}
 
-	// Start command executor
-	wg.Go(func() error {
-		cmdexe := new(commander.CommandExecutor)
-		ccli := client.New(cmdexe, cfg.Label, cfg.Label)
 	grpcAddr := cfg.GRPCURL
 	if grpcAddr == "" {
 		grpcAddr = cfg.BackendURL
 	}
 	grpcAddr = strings.TrimPrefix(grpcAddr, "http://")
 	grpcAddr = strings.TrimPrefix(grpcAddr, "https://")
+	// Start command executor
+	wg.Go(func() error {
+		cmdexe := new(commander.CommandExecutor)
+		ccli := client.New(cmdexe, cfg.Label, cfg.Label)
 		return ccli.HandleCommands(ctx, grpcAddr, creds)
 	})
 
 	// Start log collectors
 	if len(cfg.Services) > 0 {
-		grpcAddr := cfg.GRPCURL
-		if grpcAddr == "" {
-			grpcAddr = cfg.BackendURL
-		}
-		grpcAddr = strings.TrimPrefix(grpcAddr, "http://")
-		grpcAddr = strings.TrimPrefix(grpcAddr, "https://")
-
+		wg.Go(func() error {
 			conn, err := grpc.NewClient(grpcAddr, grpc.WithTransportCredentials(creds))
 			if err != nil {
-			lgr.Error("Failed to connect to gRPC", "err", err)
-			os.Exit(1)
+				return fmt.Errorf("failed to connect to gRPC: %w", err)
 			}
 			defer func() { _ = conn.Close() }()
 
 			ccli := proto.NewCollectorClient(conn)
 
+			svcWg := new(errgroup.Group)
 			for _, svc := range cfg.Services {
 				svc := svc
 				var src logsource.LogSource
@@ -135,25 +129,21 @@ func main() {
 				case "journald":
 					src, err = journald.New(svc, os.Getenv("JOURNALD_LOGDIR"))
 					if err != nil {
-					lgr.Error("Failed to create journald source", "service", svc.Name, "err", err)
-					os.Exit(1)
+						return fmt.Errorf("failed to create journald source %q: %w", svc.Name, err)
 					}
 				case "file":
 					if svc.Path == nil {
-					lgr.Error("Path is required for file log source", "service", svc.Name)
-					os.Exit(1)
+						return fmt.Errorf("path is required for file log source %q", svc.Name)
 					}
 					src, err = file.New(*svc.Path)
 					if err != nil {
-					lgr.Error("Failed to create file source", "service", svc.Name, "err", err)
-					os.Exit(1)
+						return fmt.Errorf("failed to create file source %q: %w", svc.Name, err)
 					}
 				default:
-				lgr.Error("Unknown log source type", "type", svc.Type, "service", svc.Name)
-				os.Exit(1)
+					return fmt.Errorf("unknown log source type %q for service %q", svc.Type, svc.Name)
 				}
 
-			wg.Go(func() error {
+				svcWg.Go(func() error {
 					lgr.Info("Starting log stream", "service", svc.Name)
 
 					// First, flush any buffered logs from offline period
@@ -199,6 +189,8 @@ func main() {
 					}
 				})
 			}
+			return svcWg.Wait()
+		})
 	}
 
 	if err := wg.Wait(); err != nil {