[#666] cmd/neofs-adm: Initial app structure with config init command

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

cmd/neofs-adm/internal/modules/root.go

@@ -0,0 +1,63 @@
+package modules
+
+import (
+	"fmt"
+
+	"github.com/nspcc-dev/neofs-node/cmd/neofs-adm/internal/modules/config"
+	"github.com/nspcc-dev/neofs-node/misc"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+var (
+	rootCmd = &cobra.Command{
+		Use:   "neofs-adm",
+		Short: "NeoFS Administrative Tool",
+		Long: `NeoFS Administrative Tool provides functions to setup and
+manage NeoFS network deployment.`,
+		RunE:         entryPoint,
+		SilenceUsage: true,
+	}
+
+	configFlag = "config"
+)
+
+func init() {
+	cobra.OnInitialize(func() { initConfig(rootCmd) })
+	// we need to init viper config to bind viper and cobra configurations for
+	// rpc endpoint, alphabet wallet dir, key credentials, etc.
+
+	rootCmd.PersistentFlags().StringP(configFlag, "c", "", "config file")
+	rootCmd.Flags().Bool("version", false, "application version")
+
+	rootCmd.AddCommand(config.RootCmd)
+}
+
+func Execute() error {
+	return rootCmd.Execute()
+}
+
+func entryPoint(cmd *cobra.Command, args []string) error {
+	printVersion, err := cmd.Flags().GetBool("version")
+	if err == nil && printVersion {
+		fmt.Printf("Version: %s \nBuild: %s \nDebug: %s\n",
+			misc.Version,
+			misc.Build,
+			misc.Debug,
+		)
+		return nil
+	}
+
+	return cmd.Usage()
+}
+
+func initConfig(cmd *cobra.Command) {
+	configFile, err := cmd.Flags().GetString(configFlag)
+	if err != nil || configFile == "" {
+		return
+	}
+
+	viper.SetConfigType("yml")
+	viper.SetConfigFile(configFile)
+	_ = viper.ReadInConfig() // if config file is set but unavailable, ignore it
+}