add export key command (Layr-Labs#22)

* add export key command

* fix lint

* make it less comlicated

* add test for filename

* fix lint

Author: shrimalmadhur

pkg/operator/keys.go

@@ -14,6 +14,7 @@ func KeysCmd(p utils.Prompter) *cli.Command {
 			keys.CreateCmd(p),
 			keys.ListCmd(),
 			keys.ImportCmd(p),
+			keys.ExportCmd(p),
 		},
 	}
 

pkg/operator/keys/export.go

@@ -0,0 +1,134 @@
+package keys
+
+import (
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/Layr-Labs/eigenlayer-cli/pkg/utils"
+	"github.com/Layr-Labs/eigensdk-go/crypto/bls"
+	"github.com/Layr-Labs/eigensdk-go/crypto/ecdsa"
+	"github.com/urfave/cli/v2"
+)
+
+func ExportCmd(p utils.Prompter) *cli.Command {
+	exportCmd := &cli.Command{
+		Name:      "export",
+		Usage:     "Used to export existing keys from local keystore",
+		UsageText: "export --key-type <key-type> [flags] [keyname]",
+		Description: `Used to export ecdsa and bls key from local keystore
+
+keyname - This will be the name of the key to be imported. If the path of keys is
+different from default path created by "create"/"import" command, then provide the
+full path using --key-path flag.
+
+If both keyname is provided and --key-path flag is provided, then keyname will be used. 
+
+use --key-type ecdsa/bls to export ecdsa/bls key. 
+- ecdsa - exported key should be plaintext hex encoded private key
+- bls - exported key should be plaintext bls private key
+
+It will prompt for password to encrypt the key.
+
+This command will import keys from $HOME/.eigenlayer/operator_keys/ location
+
+But if you want it to export from a different location, use --key-path flag`,
+
+		Flags: []cli.Flag{
+			&KeyTypeFlag,
+			&KeyPathFlag,
+		},
+		Action: func(c *cli.Context) error {
+			keyType := c.String(KeyTypeFlag.Name)
+
+			keyName := c.Args().Get(0)
+			if err := validateKeyName(keyName); err != nil {
+				return err
+			}
+
+			keyPath := c.String(KeyPathFlag.Name)
+			if len(keyPath) == 0 && len(keyName) == 0 {
+				return errors.New("one of keyname or --key-path is required")
+			}
+
+			if len(keyPath) > 0 && len(keyName) > 0 {
+				return errors.New("keyname and --key-path both are provided. Please provide only one")
+			}
+
+			filePath, err := getKeyPath(keyPath, keyName, keyType)
+			if err != nil {
+				return err
+			}
+
+			confirm, err := p.Confirm("This will show your private key. Are you sure you want to export?")
+			if err != nil {
+				return err
+			}
+			if !confirm {
+				return nil
+			}
+
+			password, err := p.InputHiddenString("Enter password to decrypt the key", "", func(s string) error {
+				return nil
+			})
+			if err != nil {
+				return err
+			}
+			fmt.Println("exporting key from: ", filePath)
+
+			privateKey, err := getPrivateKey(keyType, filePath, password)
+			if err != nil {
+				return err
+			}
+			fmt.Println("Private key: ", privateKey)
+			return nil
+		},
+	}
+
+	return exportCmd
+}
+
+func getPrivateKey(keyType string, filePath string, password string) (string, error) {
+	switch keyType {
+	case KeyTypeECDSA:
+		key, err := ecdsa.ReadKey(filePath, password)
+		if err != nil {
+			return "", err
+		}
+		return hex.EncodeToString(key.D.Bytes()), nil
+	case KeyTypeBLS:
+		key, err := bls.ReadPrivateKeyFromFile(filePath, password)
+		if err != nil {
+			return "", err
+		}
+		return key.PrivKey.String(), nil
+	default:
+		return "", ErrInvalidKeyType
+	}
+}
+
+func getKeyPath(keyPath string, keyName string, keyType string) (string, error) {
+	homePath, err := os.UserHomeDir()
+	if err != nil {
+		return "", err
+	}
+
+	var filePath string
+	if len(keyName) > 0 {
+		switch keyType {
+		case KeyTypeECDSA:
+			filePath = filepath.Join(homePath, OperatorKeystoreSubFolder, keyName+".ecdsa.key.json")
+		case KeyTypeBLS:
+			filePath = filepath.Join(homePath, OperatorKeystoreSubFolder, keyName+".bls.key.json")
+		default:
+			return "", ErrInvalidKeyType
+		}
+
+	} else {
+		filePath = filepath.Clean(keyPath)
+	}
+
+	return filePath, nil
+}

pkg/operator/keys/export_test.go

@@ -0,0 +1,55 @@
+package keys
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetKeyPath(t *testing.T) {
+	homePath, err := os.UserHomeDir()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tests := []struct {
+		name         string
+		keyType      string
+		keyPath      string
+		keyName      string
+		err          error
+		expectedPath string
+	}{
+		{
+			name:         "correct key path using keyname",
+			keyType:      KeyTypeECDSA,
+			keyName:      "test",
+			err:          nil,
+			expectedPath: filepath.Join(homePath, OperatorKeystoreSubFolder, "test.ecdsa.key.json"),
+		},
+		{
+			name:         "correct key path using keypath",
+			keyType:      KeyTypeECDSA,
+			keyPath:      filepath.Join(homePath, "x.json"),
+			err:          nil,
+			expectedPath: filepath.Join(homePath, "x.json"),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			path, err := getKeyPath(tt.keyPath, tt.keyName, tt.keyType)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if tt.err != nil {
+				assert.EqualError(t, err, tt.err.Error())
+			} else {
+				assert.Equal(t, tt.expectedPath, path)
+			}
+		})
+	}
+}

pkg/operator/keys/flags.go

@@ -17,4 +17,11 @@ var (
 		Usage:   "Use this flag to skip password validation",
 		EnvVars: []string{"INSECURE"},
 	}
+
+	KeyPathFlag = cli.StringFlag{
+		Name:    "key-path",
+		Aliases: []string{"p"},
+		Usage:   "Use this flag to specify the path of the key",
+		EnvVars: []string{"KEY_PATH"},
+	}
 )