signer: implement account_Version on external API

accounts/external/backend.go

@@ -1,7 +1,6 @@
 package external
 
 import (
-	"errors"
 	"fmt"
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/accounts"
@@ -31,7 +30,7 @@ func NewExternalBackend(endpoint string) (*ExternalBackend, error) {
 		return nil, err
 	}
 	return &ExternalBackend{
-		signers: []accounts.Wallet{ signer},
+		signers: []accounts.Wallet{signer},
 	}, nil
 }
 
@@ -48,6 +47,7 @@ func (eb *ExternalBackend) Subscribe(sink chan<- accounts.WalletEvent) event.Sub
 type ExternalSigner struct {
 	client   *rpc.Client
 	endpoint string
+	status   string
 	cacheMu  sync.RWMutex
 	cache    []accounts.Account
 }
@@ -57,10 +57,17 @@ func NewExternalSigner(endpoint string) (*ExternalSigner, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &ExternalSigner{
+	extsigner := &ExternalSigner{
 		client:   client,
 		endpoint: endpoint,
-	}, nil
+	}
+	// Check if reachable
+	version, err := extsigner.pingVersion()
+	if err != nil {
+		return nil, err
+	}
+	extsigner.status = fmt.Sprintf("ok [version=%v]", version)
+	return extsigner, nil
 }
 
 func (api *ExternalSigner) URL() accounts.URL {
@@ -71,7 +78,7 @@ func (api *ExternalSigner) URL() accounts.URL {
 }
 
 func (api *ExternalSigner) Status() (string, error) {
-	return "ok", nil
+	return api.status, nil
 }
 
 func (api *ExternalSigner) Open(passphrase string) error {
@@ -107,8 +114,8 @@ func (api *ExternalSigner) Accounts() []accounts.Account {
 func (api *ExternalSigner) Contains(account accounts.Account) bool {
 	api.cacheMu.RLock()
 	defer api.cacheMu.RUnlock()
-	for _, a := range api.cache{
-		if a.Address == account.Address && (account.URL == (accounts.URL{}) || account.URL == api.URL()){
+	for _, a := range api.cache {
+		if a.Address == account.Address && (account.URL == (accounts.URL{}) || account.URL == api.URL()) {
 			return true
 		}
 	}
@@ -134,11 +141,10 @@ func (api *ExternalSigner) SignCliqueHeader(account accounts.Account, header *ty
 	return api.signHash(account, accounts.CliqueHash(header).Bytes())
 }
 
-func (api *ExternalSigner) SignText(account accounts.Account, text []byte)([]byte, error){
+func (api *ExternalSigner) SignText(account accounts.Account, text []byte) ([]byte, error) {
 	return api.signHash(account, accounts.TextHash(text))
 }
 
-
 func (api *ExternalSigner) SignTx(account accounts.Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
 	res := ethapi.SignTransactionResult{}
 	to := common.NewMixedcaseAddress(*tx.To())
@@ -174,17 +180,8 @@ func (api *ExternalSigner) listAccounts() ([]common.Address, error) {
 	}
 	return res, nil
 }
-func (api *ExternalSigner) newAccount() (common.Address, error) {
-	var res accounts.Account
-	if err := api.client.Call(&res, "account_new"); err != nil {
-		return common.Address{}, err
-	}
-	return res.Address, nil
-}
+
 func (api *ExternalSigner) signCliqueBlock(a common.Address, rlpBlock hexutil.Bytes) (hexutil.Bytes, error) {
-	if api == nil {
-		return nil, errors.New("External API not initialized")
-	}
 	var sig hexutil.Bytes
 	if err := api.client.Call(&sig, "account_signData", "application/clique", a, rlpBlock); err != nil {
 		return nil, err
@@ -195,3 +192,11 @@ func (api *ExternalSigner) signCliqueBlock(a common.Address, rlpBlock hexutil.By
 	sig[64] -= 27 // Transform V from 27/28 to 0/1 for Clique use
 	return sig, nil
 }
+
+func (api *ExternalSigner) pingVersion() (string, error) {
+	var v string
+	if err := api.client.Call(&v, "account_version"); err != nil {
+		return "", err
+	}
+	return v, nil
+}

cmd/clef/main.go

@@ -49,12 +49,6 @@ import (
 	"gopkg.in/urfave/cli.v1"
 )
 
-// ExternalAPIVersion -- see extapi_changelog.md
-const ExternalAPIVersion = "4.0.0"
-
-// InternalAPIVersion -- see intapi_changelog.md
-const InternalAPIVersion = "3.0.0"
-
 const legalWarning = `
 WARNING! 
 
@@ -479,8 +473,8 @@ func signer(c *cli.Context) error {
 	}
 	ui.OnSignerStartup(core.StartupInfo{
 		Info: map[string]interface{}{
-			"extapi_version": ExternalAPIVersion,
-			"intapi_version": InternalAPIVersion,
+			"extapi_version": core.ExternalAPIVersion,
+			"intapi_version": core.InternalAPIVersion,
 			"extapi_http":    extapiURL,
 			"extapi_ipc":     ipcapiURL,
 		},

signer/core/api.go

@@ -36,8 +36,14 @@ import (
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
-// numberOfAccountsToDerive For hardware wallets, the number of accounts to derive
-const numberOfAccountsToDerive = 10
+const (
+	// numberOfAccountsToDerive For hardware wallets, the number of accounts to derive
+	numberOfAccountsToDerive = 10
+	// ExternalAPIVersion -- see extapi_changelog.md
+	ExternalAPIVersion = "4.0.0"
+	// InternalAPIVersion -- see intapi_changelog.md
+	InternalAPIVersion = "3.0.0"
+)
 
 // ExternalAPI defines the external API through which signing requests are made.
 type ExternalAPI interface {
@@ -47,7 +53,7 @@ type ExternalAPI interface {
 	New(ctx context.Context) (accounts.Account, error)
 	// SignTransaction request to sign the specified transaction
 	SignTransaction(ctx context.Context, args SendTxArgs, methodSelector *string) (*ethapi.SignTransactionResult, error)
-	// Sign - request to sign the given data (plus prefix)
+	// Sign - resquest to sign the given data (plus prefix)
 	Sign(ctx context.Context, addr common.MixedcaseAddress, data hexutil.Bytes) (hexutil.Bytes, error)
 	// Export - request to export an account
 	Export(ctx context.Context, addr common.Address) (json.RawMessage, error)
@@ -55,6 +61,7 @@ type ExternalAPI interface {
 	// Should be moved to Internal API, in next phase when we have
 	// bi-directional communication
 	//Import(ctx context.Context, keyJSON json.RawMessage) (Account, error)
+	Version(ctx context.Context) (string, error)
 }
 
 // SignerUI specifies what method a UI needs to implement to be able to be used as a UI for the signer
@@ -610,3 +617,9 @@ func (api *SignerAPI) Import(ctx context.Context, keyJSON json.RawMessage) (Acco
 	}
 	return Account{Typ: "Account", URL: acc.URL, Address: acc.Address}, nil
 }
+
+// Returns the external api version. This method does not require user acceptance. Available methods are
+// available via enumeration anyway, and this info does not contain user-specific data
+func (api *SignerAPI) Version(ctx context.Context) (string, error) {
+	return ExternalAPIVersion, nil
+}

signer/core/auditlog.go

@@ -80,14 +80,13 @@ func (l *AuditLogger) Export(ctx context.Context, addr common.Address) (json.Raw
 	return j, e
 }
 
-//func (l *AuditLogger) Import(ctx context.Context, keyJSON json.RawMessage) (Account, error) {
-//	// Don't actually log the json contents
-//	l.log.Info("Import", "type", "request", "metadata", MetadataFromContext(ctx).String(),
-//		"keyJSON size", len(keyJSON))
-//	a, e := l.api.Import(ctx, keyJSON)
-//	l.log.Info("Import", "type", "response", "addr", a.String(), "error", e)
-//	return a, e
-//}
+func (l *AuditLogger) Version(ctx context.Context) (string, error) {
+	l.log.Info("Version", "type", "request", "metadata", MetadataFromContext(ctx).String())
+	data, err := l.api.Version(ctx)
+	l.log.Info("Version", "type", "response", "data", data, "error", err)
+	return data, err
+
+}
 
 func NewAuditLogger(path string, api ExternalAPI) (*AuditLogger, error) {
 	l := log.New("api", "signer")