[#76] Implement accounting.balance command in CLI

It prints result as a float type value. With verbose flag
it prints decimal precision and value.

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

cmd/neofs-cli/modules/accounting.go

@@ -1,8 +1,11 @@
 package cmd
 
 import (
+	"context"
 	"fmt"
+	"math"
 
+	"github.com/nspcc-dev/neofs-api-go/pkg/accounting"
 	"github.com/spf13/cobra"
 )
 
@@ -11,13 +14,39 @@ var accountingCmd = &cobra.Command{
 	Use:   "accounting",
 	Short: "Operations with accounts and balances",
 	Long:  `Operations with accounts and balances`,
-	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("accounting called")
+}
+
+var accountingBalanceCmd = &cobra.Command{
+	Use:   "balance",
+	Short: "Get internal balance of NeoFS account",
+	Long:  `Get internal balance of NeoFS account`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		var (
+			response *accounting.Decimal
+			err      error
+			ctx      = context.Background()
+		)
+
+		cli, err := getSDKClient()
+		if err != nil {
+			return err
+		}
+
+		response, err = cli.GetSelfBalance(ctx)
+		if err != nil {
+			return fmt.Errorf("rpc error: %w", err)
+		}
+
+		// print to stdout
+		prettyPrintDecimal(response)
+
+		return nil
 	},
 }
 
 func init() {
 	rootCmd.AddCommand(accountingCmd)
+	accountingCmd.AddCommand(accountingBalanceCmd)
 
 	// Here you will define your flags and configuration settings.
 
@@ -29,3 +58,22 @@ func init() {
 	// is called directly, e.g.:
 	// accountingCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
 }
+
+func prettyPrintDecimal(decimal *accounting.Decimal) {
+	if decimal == nil {
+		return
+	}
+
+	if verbose {
+		fmt.Println("value:", decimal.GetValue())
+		fmt.Println("precision:", decimal.GetPrecision())
+	} else {
+		// divider = 10^{precision}; v:365, p:2 => 365 / 10^2 = 3.65
+		divider := math.Pow(10, float64(decimal.GetPrecision()))
+
+		// %0.8f\n for precision 8
+		format := fmt.Sprintf("%%0.%df\n", decimal.GetPrecision())
+
+		fmt.Printf(format, float64(decimal.GetValue())/divider)
+	}
+}

cmd/neofs-cli/modules/root.go

@@ -7,6 +7,7 @@ import (
 	"os"
 
 	"github.com/mitchellh/go-homedir"
+	"github.com/nspcc-dev/neofs-api-go/pkg/client"
 	crypto "github.com/nspcc-dev/neofs-crypto"
 	"github.com/nspcc-dev/neofs-node/pkg/network"
 	"github.com/spf13/cobra"
@@ -111,3 +112,24 @@ func getEndpointAddress() (*network.Address, error) {
 
 	return addr, nil
 }
+
+// getSDKClient returns default neofs-api-go sdk client. Consider using
+// opts... to provide TTL or other global configuration flags.
+func getSDKClient() (*client.Client, error) {
+	key, err := getKey()
+	if err != nil {
+		return nil, err
+	}
+
+	netAddr, err := getEndpointAddress()
+	if err != nil {
+		return nil, err
+	}
+
+	ipAddr, err := netAddr.IPAddrString()
+	if err != nil {
+		return nil, errInvalidEndpoint
+	}
+
+	return client.New(key, client.WithAddress(ipAddr))
+}