server+lntest: extract ErrServerNotActive error

rpcserver.go

@@ -1257,8 +1257,7 @@ func (r *rpcServer) ConnectPeer(ctx context.Context,
 	// The server hasn't yet started, so it won't be able to service any of
 	// our requests, so we'll bail early here.
 	if !r.server.Started() {
-		return nil, fmt.Errorf("chain backend is still syncing, server " +
-			"not active yet")
+		return nil, ErrServerNotActive
 	}
 
 	if in.Addr == nil {
@@ -1311,8 +1310,7 @@ func (r *rpcServer) DisconnectPeer(ctx context.Context,
 	rpcsLog.Debugf("[disconnectpeer] from peer(%s)", in.PubKey)
 
 	if !r.server.Started() {
-		return nil, fmt.Errorf("chain backend is still syncing, server " +
-			"not active yet")
+		return nil, ErrServerNotActive
 	}
 
 	// First we'll validate the string passed in within the request to
@@ -1398,8 +1396,7 @@ func (r *rpcServer) OpenChannel(in *lnrpc.OpenChannelRequest,
 		in.LocalFundingAmount, in.PushSat)
 
 	if !r.server.Started() {
-		return fmt.Errorf("chain backend is still syncing, server " +
-			"not active yet")
+		return ErrServerNotActive
 	}
 
 	localFundingAmt := btcutil.Amount(in.LocalFundingAmount)
@@ -1558,8 +1555,7 @@ func (r *rpcServer) OpenChannelSync(ctx context.Context,
 	// syncing, as otherwise we may not be able to obtain the relevant
 	// notifications.
 	if !r.server.Started() {
-		return nil, fmt.Errorf("chain backend is still syncing, server " +
-			"not active yet")
+		return nil, ErrServerNotActive
 	}
 
 	// Creation of channels before the wallet syncs up is currently
@@ -3205,8 +3201,7 @@ func (r *rpcServer) sendPayment(stream *paymentStream) error {
 	// syncing as we may be trying to sent a payment over a "stale"
 	// channel.
 	if !r.server.Started() {
-		return fmt.Errorf("chain backend is still syncing, server " +
-			"not active yet")
+		return ErrServerNotActive
 	}
 
 	// TODO(roasbeef): check payment filter to see if already used?
@@ -3396,8 +3391,7 @@ func (r *rpcServer) sendPaymentSync(ctx context.Context,
 	// syncing as we may be trying to sent a payment over a "stale"
 	// channel.
 	if !r.server.Started() {
-		return nil, fmt.Errorf("chain backend is still syncing, server " +
-			"not active yet")
+		return nil, ErrServerNotActive
 	}
 
 	// First we'll attempt to map the proto describing the next payment to