build: switch to slog Handlers

build/handler_sets.go

@@ -169,3 +169,27 @@ func (r *reducedSet) WithGroup(name string) slog.Handler {
 
 // A compile-time check to ensure that handlerSet implements slog.Handler.
 var _ slog.Handler = (*reducedSet)(nil)
+
+// subLogGenerator implements the SubLogCreator backed by a Handler.
+type subLogGenerator struct {
+	handler Handler
+}
+
+// newSubLogGenerator constructs a new subLogGenerator from a Handler.
+func newSubLogGenerator(handler Handler) *subLogGenerator {
+	return &subLogGenerator{
+		handler: handler,
+	}
+}
+
+// Logger returns a new logger for a particular sub-system.
+//
+// NOTE: this is part of the SubLogCreator interface.
+func (b *subLogGenerator) Logger(subsystemTag string) btclog.Logger {
+	handler := b.handler.Subsystem(subsystemTag)
+
+	return btclog.NewSLogger(handler)
+}
+
+// A compile-time check to ensure that handlerSet implements slog.Handler.
+var _ SubLogCreator = (*subLogGenerator)(nil)

build/log.go

@@ -1,7 +1,7 @@
 package build
 
 import (
-	"io"
+	"os"
 
 	"github.com/btcsuite/btclog"
 )
@@ -34,17 +34,6 @@ func (t LogType) String() string {
 	}
 }
 
-// LogWriter is a stub type whose behavior can be changed using the build flags
-// "stdlog" and "nolog". The default behavior is to write to both stdout and the
-// RotatorPipe. Passing "stdlog" will cause it only to write to stdout, and
-// "nolog" implements Write as a no-op.
-type LogWriter struct {
-	// RotatorPipe is the write-end pipe for writing to the log rotator.  It
-	// is written to by the Write method of the LogWriter type. This only
-	// needs to be set if neither the stdlog or nolog builds are set.
-	RotatorPipe *io.PipeWriter
-}
-
 // NewSubLogger constructs a new subsystem log from the current LogWriter
 // implementation. This is primarily intended for use with stdlog, as the actual
 // writer is shared amongst all instantiations.
@@ -78,7 +67,7 @@ func NewSubLogger(subsystem string,
 		// that they share the same backend, since all output is written
 		// to std out.
 		case LogTypeStdOut:
-			backend := btclog.NewBackend(&LogWriter{})
+			backend := btclog.NewBackend(os.Stdout)
 			logger := backend.Logger(subsystem)
 
 			// Set the logging level of the stdout logger to use the

build/log_default.go

@@ -3,17 +3,6 @@
 
 package build
 
-import "os"
-
 // LoggingType is a log type that writes to both stdout and the log rotator, if
 // present.
 const LoggingType = LogTypeDefault
-
-// Write writes the byte slice to both stdout and the log rotator, if present.
-func (w *LogWriter) Write(b []byte) (int, error) {
-	os.Stdout.Write(b)
-	if w.RotatorPipe != nil {
-		w.RotatorPipe.Write(b)
-	}
-	return len(b), nil
-}

build/log_nolog.go

@@ -5,8 +5,3 @@ package build
 
 // LoggingType is a log type that writes no logs.
 const LoggingType = LogTypeNone
-
-// Write is a noop.
-func (w *LogWriter) Write(b []byte) (int, error) {
-	return len(b), nil
-}

build/log_stdlog.go

@@ -3,13 +3,5 @@
 
 package build
 
-import "os"
-
 // LoggingType is a log type that only writes to stdout.
 const LoggingType = LogTypeStdOut
-
-// Write writes the provided byte slice to stdout.
-func (w *LogWriter) Write(b []byte) (int, error) {
-	os.Stdout.Write(b)
-	return len(b), nil
-}

build/logrotator.go

@@ -12,7 +12,8 @@ import (
 // RotatingLogWriter is a wrapper around the LogWriter that supports log file
 // rotation.
 type RotatingLogWriter struct {
-	logWriter *LogWriter
+	// pipe is the write-end pipe for writing to the log rotator
+	pipe *io.PipeWriter
 
 	rotator *rotator.Rotator
 }
@@ -21,8 +22,8 @@ type RotatingLogWriter struct {
 //
 // NOTE: `InitLogRotator` must be called to set up log rotation after creating
 // the writer.
-func NewRotatingLogWriter(w *LogWriter) *RotatingLogWriter {
-	return &RotatingLogWriter{logWriter: w}
+func NewRotatingLogWriter() *RotatingLogWriter {
+	return &RotatingLogWriter{}
 }
 
 // InitLogRotator initializes the log file rotator to write logs to logFile and
@@ -57,11 +58,19 @@ func (r *RotatingLogWriter) InitLogRotator(logFile string, maxLogFileSize int,
 		}
 	}()
 
-	r.logWriter.RotatorPipe = pw
+	r.pipe = pw
 
 	return nil
 }
 
+// Write writes the byte slice to both stdout and the log rotator, if present.
+func (r *RotatingLogWriter) Write(b []byte) (int, error) {
+	if r.rotator != nil {
+		return r.rotator.Write(b)
+	}
+	return len(b), nil
+}
+
 // Close closes the underlying log rotator if it has already been created.
 func (r *RotatingLogWriter) Close() error {
 	if r.rotator != nil {

build/sub_logger.go

@@ -2,7 +2,6 @@ package build
 
 import (
 	"fmt"
-	"io"
 	"sort"
 	"strings"
 	"sync"
@@ -30,10 +29,12 @@ type SubLoggerManager struct {
 var _ LeveledSubLogger = (*SubLoggerManager)(nil)
 
 // NewSubLoggerManager constructs a new SubLoggerManager.
-func NewSubLoggerManager(w io.Writer) *SubLoggerManager {
+func NewSubLoggerManager(handlers ...Handler) *SubLoggerManager {
 	return &SubLoggerManager{
-		loggers:   SubLoggers{},
-		genLogger: btclog.NewBackend(w),
+		loggers: SubLoggers{},
+		genLogger: newSubLogGenerator(
+			newHandlerSet(btclog.LevelInfo, handlers...),
+		),
 	}
 }
 

config.go

@@ -495,7 +495,6 @@ type Config struct {
 	// LogMgr is the root logger that all the daemon's subloggers are
 	// hooked up to.
 	LogMgr     *build.SubLoggerManager
-	LogWriter  *build.LogWriter
 	LogRotator *build.RotatingLogWriter
 
 	// networkDir is the path to the directory of the currently active
@@ -713,7 +712,7 @@ func DefaultConfig() Config {
 		MaxChannelFeeAllocation:   htlcswitch.DefaultMaxLinkFeeAllocation,
 		MaxCommitFeeRateAnchors:   lnwallet.DefaultAnchorsCommitMaxFeeRateSatPerVByte,
 		MaxFeeExposure:            uint64(htlcswitch.DefaultMaxFeeExposure.ToSatoshis()),
-		LogWriter:                 &build.LogWriter{},
+		LogRotator:                build.NewRotatingLogWriter(),
 		DB:                        lncfg.DefaultDB(),
 		Cluster:                   lncfg.DefaultCluster(),
 		RPCMiddleware:             lncfg.DefaultRPCMiddleware(),
@@ -1435,14 +1434,20 @@ func ValidateConfig(cfg Config, interceptor signal.Interceptor, fileParser,
 		lncfg.NormalizeNetwork(cfg.ActiveNetParams.Name),
 	)
 
-	// A log writer must be passed in, otherwise we can't function and would
-	// run into a panic later on.
-	if cfg.LogWriter == nil {
-		return nil, mkErr("log writer missing in config")
+	var (
+		cliLogHander = build.NewCLIHandler(os.Stdout, false)
+		logHandlers  []build.Handler
+	)
+	switch build.LoggingType {
+	case build.LogTypeStdOut:
+		logHandlers = []build.Handler{cliLogHander}
+	case build.LogTypeDefault:
+		logHandlers = []build.Handler{
+			cliLogHander,
+			build.NewLogFileHandler(cfg.LogRotator),
+		}
 	}
-
-	cfg.LogRotator = build.NewRotatingLogWriter(cfg.LogWriter)
-	cfg.LogMgr = build.NewSubLoggerManager(cfg.LogWriter)
+	cfg.LogMgr = build.NewSubLoggerManager(logHandlers...)
 
 	// Special show command to list supported subsystems and exit.
 	if cfg.DebugLevel == "show" {