accounts: add label to account

Author: guggero

accounts/interface.go

@@ -104,6 +104,10 @@ type OffChainBalanceAccount struct {
 	// Payments is a list of all payments that are associated with the
 	// account and the last status we were aware of.
 	Payments map[lntypes.Hash]*PaymentEntry
+
+	// Label is an optional label that can be set for the account. If it is
+	// not empty then it must be unique.
+	Label string
 }
 
 // HasExpired returns true if the account has an expiration date set and that
@@ -180,8 +184,8 @@ var (
 type Store interface {
 	// NewAccount creates a new OffChainBalanceAccount with the given
 	// balance and a randomly chosen ID.
-	NewAccount(balance lnwire.MilliSatoshi,
-		expirationDate time.Time) (*OffChainBalanceAccount, error)
+	NewAccount(balance lnwire.MilliSatoshi, expirationDate time.Time,
+		label string) (*OffChainBalanceAccount, error)
 
 	// UpdateAccount writes an account to the database, overwriting the
 	// existing one if it exists.

accounts/rpcserver.go

@@ -70,7 +70,7 @@ func (s *RPCServer) CreateAccount(ctx context.Context,
 	balanceMsat = lnwire.NewMSatFromSatoshis(balance)
 
 	// Create the actual account in the macaroon account store.
-	account, err := s.service.NewAccount(balanceMsat, expirationDate)
+	account, err := s.service.NewAccount(balanceMsat, expirationDate, "")
 	if err != nil {
 		return nil, fmt.Errorf("unable to create account: %v", err)
 	}

accounts/service.go

@@ -212,12 +212,13 @@ func (s *InterceptorService) Start(lightningClient lndclient.LightningClient,
 // NewAccount creates a new OffChainBalanceAccount with the given balance and a
 // randomly chosen ID.
 func (s *InterceptorService) NewAccount(balance lnwire.MilliSatoshi,
-	expirationDate time.Time) (*OffChainBalanceAccount, error) {
+	expirationDate time.Time, label string) (*OffChainBalanceAccount,
+	error) {
 
 	s.Lock()
 	defer s.Unlock()
 
-	return s.store.NewAccount(balance, expirationDate)
+	return s.store.NewAccount(balance, expirationDate, label)
 }
 
 // UpdateAccount writes an account to the database, overwriting the existing one

accounts/service_test.go

@@ -206,7 +206,9 @@ func TestAccountService(t *testing.T) {
 	}, {
 		name: "startup do not track completed payments",
 		setup: func(t *testing.T, lnd *mockLnd, s *InterceptorService) {
-			acct, err := s.store.NewAccount(1234, testExpiration)
+			acct, err := s.store.NewAccount(
+				1234, testExpiration, "",
+			)
 			require.NoError(t, err)
 
 			acct.Invoices[testHash] = struct{}{}

accounts/store.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/rand"
 	"encoding/binary"
+	"encoding/hex"
 	"fmt"
 	"os"
 	"time"
@@ -104,12 +105,39 @@ func (s *BoltStore) Close() error {
 // NewAccount creates a new OffChainBalanceAccount with the given balance and a
 // randomly chosen ID.
 func (s *BoltStore) NewAccount(balance lnwire.MilliSatoshi,
-	expirationDate time.Time) (*OffChainBalanceAccount, error) {
+	expirationDate time.Time, label string) (*OffChainBalanceAccount,
+	error) {
 
 	if balance == 0 {
 		return nil, fmt.Errorf("a new account cannot have balance of 0")
 	}
 
+	// If a label is set, it must be unique, as we use it to identify the
+	// account in some of the RPCs. It also can't be mistaken for a hex
+	// encoded account ID to avoid confusion and make it easier for the CLI
+	// to distinguish between the two.
+	if len(label) > 0 {
+		if _, err := hex.DecodeString(label); err == nil &&
+			len(label) == hex.EncodedLen(AccountIDLen) {
+
+			return nil, fmt.Errorf("the label '%s' is not allowed "+
+				"as it can be mistaken for an account ID",
+				label)
+		}
+
+		accounts, err := s.Accounts()
+		if err != nil {
+			return nil, fmt.Errorf("error checking label "+
+				"uniqueness: %w", err)
+		}
+		for _, account := range accounts {
+			if account.Label == label {
+				return nil, fmt.Errorf("an account with the "+
+					"label '%s' already exists", label)
+			}
+		}
+	}
+
 	// First, create a new instance of an account. Currently, only the type
 	// TypeInitialBalance is supported.
 	account := &OffChainBalanceAccount{
@@ -120,6 +148,7 @@ func (s *BoltStore) NewAccount(balance lnwire.MilliSatoshi,
 		LastUpdate:     time.Now(),
 		Invoices:       make(map[lntypes.Hash]struct{}),
 		Payments:       make(map[lntypes.Hash]*PaymentEntry),
+		Label:          label,
 	}
 
 	// Try storing the account in the account database, so we can keep track

accounts/store_test.go

@@ -18,11 +18,11 @@ func TestAccountStore(t *testing.T) {
 
 	// An initial balance of 0 is not allowed, but later we can reach a
 	// zero balance.
-	_, err = store.NewAccount(0, time.Time{})
+	_, err = store.NewAccount(0, time.Time{}, "")
 	require.ErrorContains(t, err, "cannot have balance of 0")
 
 	// Create an account that does not expire.
-	acct1, err := store.NewAccount(123, time.Time{})
+	acct1, err := store.NewAccount(123, time.Time{}, "foo")
 	require.NoError(t, err)
 	require.False(t, acct1.HasExpired())
 
@@ -31,6 +31,14 @@ func TestAccountStore(t *testing.T) {
 
 	assertEqualAccounts(t, acct1, dbAccount)
 
+	// Make sure we cannot create a second account with the same label.
+	_, err = store.NewAccount(123, time.Time{}, "foo")
+	require.ErrorContains(t, err, "account with the label 'foo' already")
+
+	// Make sure we cannot set a label that looks like an account ID.
+	_, err = store.NewAccount(123, time.Time{}, "0011223344556677")
+	require.ErrorContains(t, err, "is not allowed as it can be mistaken")
+
 	// Update all values of the account that we can modify.
 	acct1.CurrentBalance = -500
 	acct1.ExpirationDate = time.Now()

accounts/tlv.go

@@ -21,6 +21,7 @@ const (
 	typeExpirationDate tlv.Type = 6
 	typeInvoices       tlv.Type = 7
 	typePayments       tlv.Type = 8
+	typeLabel          tlv.Type = 9
 )
 
 func serializeAccount(account *OffChainBalanceAccount) ([]byte, error) {
@@ -34,6 +35,7 @@ func serializeAccount(account *OffChainBalanceAccount) ([]byte, error) {
 		initialBalance = uint64(account.InitialBalance)
 		currentBalance = uint64(account.CurrentBalance)
 		lastUpdate     = uint64(account.LastUpdate.UnixNano())
+		label          = []byte(account.Label)
 	)
 
 	tlvRecords := []tlv.Record{
@@ -55,6 +57,7 @@ func serializeAccount(account *OffChainBalanceAccount) ([]byte, error) {
 		tlvRecords,
 		newHashMapRecord(typeInvoices, &account.Invoices),
 		newPaymentEntryMapRecord(typePayments, &account.Payments),
+		tlv.MakePrimitiveRecord(typeLabel, &label),
 	)
 
 	tlvStream, err := tlv.NewStream(tlvRecords...)
@@ -80,6 +83,7 @@ func deserializeAccount(content []byte) (*OffChainBalanceAccount, error) {
 		expirationDate uint64
 		invoices       map[lntypes.Hash]struct{}
 		payments       map[lntypes.Hash]*PaymentEntry
+		label          []byte
 	)
 
 	tlvStream, err := tlv.NewStream(
@@ -91,6 +95,7 @@ func deserializeAccount(content []byte) (*OffChainBalanceAccount, error) {
 		tlv.MakePrimitiveRecord(typeExpirationDate, &expirationDate),
 		newHashMapRecord(typeInvoices, &invoices),
 		newPaymentEntryMapRecord(typePayments, &payments),
+		tlv.MakePrimitiveRecord(typeLabel, &label),
 	)
 	if err != nil {
 		return nil, err
@@ -108,6 +113,7 @@ func deserializeAccount(content []byte) (*OffChainBalanceAccount, error) {
 		LastUpdate:     time.Unix(0, int64(lastUpdate)),
 		Invoices:       invoices,
 		Payments:       payments,
+		Label:          string(label),
 	}
 	copy(account.ID[:], id)