loop: unify top level logger, use lnd's build pacakge for logging

client.go

@@ -134,7 +134,7 @@ func (s *Client) Run(ctx context.Context,
 	if err != nil {
 		return fmt.Errorf("GetInfo error: %v", err)
 	}
-	logger.Infof("Connected to lnd node %v with pubkey %v",
+	log.Infof("Connected to lnd node %v with pubkey %v",
 		info.Alias, hex.EncodeToString(info.IdentityPubkey[:]),
 	)
 
@@ -172,22 +172,22 @@ func (s *Client) Run(ctx context.Context,
 	}
 
 	if err != nil {
-		logger.Errorf("Swap client terminating: %v", err)
+		log.Errorf("Swap client terminating: %v", err)
 	} else {
-		logger.Info("Swap client terminating")
+		log.Info("Swap client terminating")
 	}
 
 	// Cancel all remaining active goroutines.
 	mainCancel()
 
 	// Wait for all to finish.
-	logger.Debug("Wait for executor to finish")
+	log.Debug("Wait for executor to finish")
 	s.executor.waitFinished()
 
-	logger.Debug("Wait for goroutines to finish")
+	log.Debug("Wait for goroutines to finish")
 	s.wg.Wait()
 
-	logger.Info("Swap client terminated")
+	log.Info("Swap client terminated")
 
 	return err
 }
@@ -206,7 +206,7 @@ func (s *Client) resumeSwaps(ctx context.Context,
 		}
 		swap, err := resumeLoopOutSwap(ctx, swapCfg, pend)
 		if err != nil {
-			logger.Errorf("resuming swap: %v", err)
+			log.Errorf("resuming swap: %v", err)
 			continue
 		}
 
@@ -226,7 +226,7 @@ func (s *Client) resumeSwaps(ctx context.Context,
 func (s *Client) LoopOut(globalCtx context.Context,
 	request *OutRequest) (*lntypes.Hash, error) {
 
-	logger.Infof("LoopOut %v to %v (channel: %v)",
+	log.Infof("LoopOut %v to %v (channel: %v)",
 		request.Amount, request.DestAddr,
 		request.LoopOutChannel,
 	)
@@ -276,7 +276,7 @@ func (s *Client) LoopOutQuote(ctx context.Context,
 		return nil, ErrSwapAmountTooHigh
 	}
 
-	logger.Infof("Offchain swap destination: %x", terms.SwapPaymentDest)
+	log.Infof("Offchain swap destination: %x", terms.SwapPaymentDest)
 
 	swapFee := swap.CalcFee(
 		request.Amount, terms.SwapFeeBase, terms.SwapFeeRate,

executor.go

@@ -59,7 +59,7 @@ func (s *executor) run(mainCtx context.Context,
 	// Before starting, make sure we have an up to date block height.
 	// Otherwise we might reveal a preimage for a swap that is already
 	// expired.
-	logger.Infof("Wait for first block ntfn")
+	log.Infof("Wait for first block ntfn")
 
 	var height int32
 	setHeight := func(h int32) {
@@ -77,7 +77,7 @@ func (s *executor) run(mainCtx context.Context,
 	}
 
 	// Start main event loop.
-	logger.Infof("Starting event loop at height %v", height)
+	log.Infof("Starting event loop at height %v", height)
 
 	// Signal that executor being ready with an up to date block height.
 	close(s.ready)

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/golang/protobuf v1.3.1
 	github.com/grpc-ecosystem/grpc-gateway v1.8.5
 	github.com/jessevdk/go-flags v1.4.0
+	github.com/jrick/logrotate v1.0.0
 	github.com/lightninglabs/neutrino v0.0.0-20190314214430-643615b8c132 // indirect
 	github.com/lightningnetwork/lnd v0.0.0-20190314214430-b4a1024ac74fc576c65c8074288a5ffaf6bd1ec4
 	github.com/lightningnetwork/lnd/queue v1.0.1

log.go

@@ -2,28 +2,33 @@ package loop
 
 import (
 	"fmt"
-	"os"
 
 	"github.com/btcsuite/btclog"
+	"github.com/lightningnetwork/lnd/build"
 	"github.com/lightningnetwork/lnd/lntypes"
 )
 
-// log is a logger that is initialized with no output filters.  This
-// means the package will not perform any logging by default until the caller
-// requests it.
-var (
-	backendLog     = btclog.NewBackend(logWriter{})
-	logger         = backendLog.Logger("CLIENT")
-	servicesLogger = backendLog.Logger("SERVICES")
-)
+// log is a logger that is initialized with no output filters.  This means the
+// package will not perform any logging by default until the caller requests
+// it.
+var log btclog.Logger
+
+// The default amount of logging is none.
+func init() {
+	UseLogger(build.NewSubLogger("LOOP", nil))
+}
 
-// logWriter implements an io.Writer that outputs to both standard output and
-// the write-end pipe of an initialized log rotator.
-type logWriter struct{}
+// DisableLog disables all library log output.  Logging output is disabled by
+// default until UseLogger is called.
+func DisableLog() {
+	UseLogger(btclog.Disabled)
+}
 
-func (logWriter) Write(p []byte) (n int, err error) {
-	os.Stdout.Write(p)
-	return len(p), nil
+// UseLogger uses a specified Logger to output package logging info.  This
+// should be used in preference to SetLogWriter if the caller is also using
+// btclog.
+func UseLogger(logger btclog.Logger) {
+	log = logger
 }
 
 // SwapLog logs with a short swap hash prefix.

loopout.go

@@ -50,7 +50,7 @@ func newLoopOutSwap(globalCtx context.Context, cfg *swapConfig,
 	// Generate random preimage.
 	var swapPreimage [32]byte
 	if _, err := rand.Read(swapPreimage[:]); err != nil {
-		logger.Error("Cannot generate preimage")
+		log.Error("Cannot generate preimage")
 	}
 	swapHash := lntypes.Hash(sha256.Sum256(swapPreimage[:]))
 
@@ -66,7 +66,7 @@ func newLoopOutSwap(globalCtx context.Context, cfg *swapConfig,
 
 	// Post the swap parameters to the swap server. The response contains
 	// the server revocation key and the swap and prepay invoices.
-	logger.Infof("Initiating swap request at height %v", currentHeight)
+	log.Infof("Initiating swap request at height %v", currentHeight)
 
 	swapResp, err := cfg.server.NewLoopOutSwap(globalCtx, swapHash,
 		request.Amount, receiverKey,
@@ -135,7 +135,7 @@ func resumeLoopOutSwap(reqContext context.Context, cfg *swapConfig,
 
 	hash := lntypes.Hash(sha256.Sum256(pend.Contract.Preimage[:]))
 
-	logger.Infof("Resuming swap %v", hash)
+	log.Infof("Resuming swap %v", hash)
 
 	swapKit, err := newSwapKit(
 		hash, TypeOut, cfg, &pend.Contract.SwapContract,
@@ -291,7 +291,7 @@ func (s *loopOutSwap) executeSwap(globalCtx context.Context) error {
 
 	// Verify amount if preimage hasn't been revealed yet.
 	if s.state != loopdb.StatePreimageRevealed && htlcValue < s.AmountRequested {
-		logger.Warnf("Swap amount too low, expected %v but received %v",
+		log.Warnf("Swap amount too low, expected %v but received %v",
 			s.AmountRequested, htlcValue)
 
 		s.state = loopdb.StateFailInsufficientValue
@@ -468,7 +468,7 @@ func (s *loopOutSwap) waitForConfirmedHtlc(globalCtx context.Context) (
 			case notification := <-s.blockEpochChan:
 				s.height = notification.(int32)
 
-				logger.Infof("Received block %v", s.height)
+				log.Infof("Received block %v", s.height)
 
 				if checkMaxRevealHeightExceeded() {
 					return nil, nil
@@ -653,21 +653,21 @@ func validateLoopOutContract(lnd *lndclient.LndServices,
 
 	swapFee := swapInvoiceAmt + prepayInvoiceAmt - request.Amount
 	if swapFee > request.MaxSwapFee {
-		logger.Warnf("Swap fee %v exceeding maximum of %v",
+		log.Warnf("Swap fee %v exceeding maximum of %v",
 			swapFee, request.MaxSwapFee)
 
 		return ErrSwapFeeTooHigh
 	}
 
 	if prepayInvoiceAmt > request.MaxPrepayAmount {
-		logger.Warnf("Prepay amount %v exceeding maximum of %v",
+		log.Warnf("Prepay amount %v exceeding maximum of %v",
 			prepayInvoiceAmt, request.MaxPrepayAmount)
 
 		return ErrPrepayAmountTooHigh
 	}
 
 	if response.expiry-height < MinLoopOutPreimageRevealDelta {
-		logger.Warnf("Proposed expiry %v (delta %v) too soon",
+		log.Warnf("Proposed expiry %v (delta %v) too soon",
 			response.expiry, response.expiry-height)
 
 		return ErrExpiryTooSoon

swap.go

@@ -48,7 +48,7 @@ func newSwapKit(hash lntypes.Hash, swapType Type, cfg *swapConfig,
 
 	log := &SwapLog{
 		Hash:   hash,
-		Logger: logger,
+		Logger: log,
 	}
 
 	log.Infof("Htlc address: %v", htlcAddress)