feat(client): Add flag & reading mnemonic from file (#20690)

CHANGELOG.md

@@ -42,6 +42,7 @@ Every module contains its own CHANGELOG.md. Please refer to the module you are i
 
 ### Features
 
+* (client) [#20690](https://github.com/cosmos/cosmos-sdk/pull/20690) Import mnemonic from file
 * (tests) [#20013](https://github.com/cosmos/cosmos-sdk/pull/20013) Introduce system tests to run multi node local testnet in CI
 * (runtime) [#19953](https://github.com/cosmos/cosmos-sdk/pull/19953) Implement `core/transaction.Service` in runtime.
 * (client) [#19905](https://github.com/cosmos/cosmos-sdk/pull/19905) Add grpc client config to `client.toml`.

client/keys/add.go

@@ -7,6 +7,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
+	"os"
 	"sort"
 	"strings"
 
@@ -38,6 +40,7 @@ const (
 	flagHDPath       = "hd-path"
 	flagPubKeyBase64 = "pubkey-base64"
 	flagIndiscreet   = "indiscreet"
+	flagMnemonicSrc  = "source"
 
 	// DefaultKeyPass contains the default key password for genesis transactions
 	DefaultKeyPass = "12345678"
@@ -60,6 +63,11 @@ local keystore.
 Use the --pubkey flag to add arbitrary public keys to the keystore for constructing
 multisig transactions.
 
+Use the --source flag to import mnemonic from a file in recover or interactive mode. 
+Example:
+
+	keys add testing --recover --source ./mnemonic.txt
+
 You can create and store a multisig key by passing the list of key names stored in a keyring
 and the minimum number of signatures required through --multisig-threshold. The keys are
 sorted by address, unless the flag --nosort is set.
@@ -87,6 +95,7 @@ Example:
 	f.Uint32(flagIndex, 0, "Address index number for HD derivation (less than equal 2147483647)")
 	f.String(flags.FlagKeyType, string(hd.Secp256k1Type), "Key signing algorithm to generate keys for")
 	f.Bool(flagIndiscreet, false, "Print seed phrase directly on current terminal (only valid when --no-backup is false)")
+	f.String(flagMnemonicSrc, "", "Import mnemonic from a file (only usable when recover or interactive is passed)")
 
 	// support old flags name for backwards compatibility
 	f.SetNormalizeFunc(func(f *pflag.FlagSet, name string) pflag.NormalizedName {
@@ -282,19 +291,34 @@ func runAddCmd(ctx client.Context, cmd *cobra.Command, args []string, inBuf *buf
 	var mnemonic, bip39Passphrase string
 
 	recoverFlag, _ := cmd.Flags().GetBool(flagRecover)
+	mnemonicSrc, _ := cmd.Flags().GetString(flagMnemonicSrc)
 	if recoverFlag {
-		mnemonic, err = input.GetString("Enter your bip39 mnemonic", inBuf)
-		if err != nil {
-			return err
+		if mnemonicSrc != "" {
+			mnemonic, err = readMnemonicFromFile(mnemonicSrc)
+			if err != nil {
+				return err
+			}
+		} else {
+			mnemonic, err = input.GetString("Enter your bip39 mnemonic", inBuf)
+			if err != nil {
+				return err
+			}
 		}
 
 		if !bip39.IsMnemonicValid(mnemonic) {
 			return errors.New("invalid mnemonic")
 		}
 	} else if interactive {
-		mnemonic, err = input.GetString("Enter your bip39 mnemonic, or hit enter to generate one.", inBuf)
-		if err != nil {
-			return err
+		if mnemonicSrc != "" {
+			mnemonic, err = readMnemonicFromFile(mnemonicSrc)
+			if err != nil {
+				return err
+			}
+		} else {
+			mnemonic, err = input.GetString("Enter your bip39 mnemonic, or hit enter to generate one.", inBuf)
+			if err != nil {
+				return err
+			}
 		}
 
 		if !bip39.IsMnemonicValid(mnemonic) && mnemonic != "" {
@@ -404,3 +428,17 @@ func printCreate(ctx client.Context, cmd *cobra.Command, k *keyring.Record, show
 
 	return nil
 }
+
+func readMnemonicFromFile(filePath string) (string, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	bz, err := io.ReadAll(file)
+	if err != nil {
+		return "", err
+	}
+	return string(bz), nil
+}