Release v0.3.0

vendor/github.com/lightningnetwork/lnd/build/log.go

@@ -0,0 +1,200 @@
+package build
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/btcsuite/btclog"
+)
+
+// LogType is an indicating the type of logging specified by the build flag.
+type LogType byte
+
+const (
+	// LogTypeNone indicates no logging.
+	LogTypeNone LogType = iota
+
+	// LogTypeStdOut all logging is written directly to stdout.
+	LogTypeStdOut
+
+	// LogTypeDefault logs to both stdout and a given io.PipeWriter.
+	LogTypeDefault
+)
+
+// String returns a human readable identifier for the logging type.
+func (t LogType) String() string {
+	switch t {
+	case LogTypeNone:
+		return "none"
+	case LogTypeStdOut:
+		return "stdout"
+	case LogTypeDefault:
+		return "default"
+	default:
+		return "unknown"
+	}
+}
+
+// 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.
+func NewSubLogger(subsystem string,
+	genSubLogger func(string) btclog.Logger) btclog.Logger {
+
+	switch Deployment {
+
+	// For production builds, generate a new subsystem logger from the
+	// primary log backend. If no function is provided, logging will be
+	// disabled.
+	case Production:
+		if genSubLogger != nil {
+			return genSubLogger(subsystem)
+		}
+
+	// For development builds, we must handle two distinct types of logging:
+	// unit tests and running the live daemon, e.g. for integration testing.
+	case Development:
+		switch LoggingType {
+
+		// Default logging is used when running the standalone daemon.
+		// We'll use the optional sublogger constructor to mimic the
+		// production behavior.
+		case LogTypeDefault:
+			if genSubLogger != nil {
+				return genSubLogger(subsystem)
+			}
+
+		// Logging to stdout is used in unit tests. It is not important
+		// that they share the same backend, since all output is written
+		// to std out.
+		case LogTypeStdOut:
+			backend := btclog.NewBackend(&LogWriter{})
+			logger := backend.Logger(subsystem)
+
+			// Set the logging level of the stdout logger to use the
+			// configured logging level specified by build flags.
+			level, _ := btclog.LevelFromString(LogLevel)
+			logger.SetLevel(level)
+
+			return logger
+		}
+	}
+
+	// For any other configurations, we'll disable logging.
+	return btclog.Disabled
+}
+
+// SubLoggers is a type that holds a map of subsystem loggers keyed by their
+// subsystem name.
+type SubLoggers map[string]btclog.Logger
+
+// LeveledSubLogger provides the ability to retrieve the subsystem loggers of
+// a logger and set their log levels individually or all at once.
+type LeveledSubLogger interface {
+	// SubLoggers returns the map of all registered subsystem loggers.
+	SubLoggers() SubLoggers
+
+	// SupportedSubsystems returns a slice of strings containing the names
+	// of the supported subsystems. Should ideally correspond to the keys
+	// of the subsystem logger map and be sorted.
+	SupportedSubsystems() []string
+
+	// SetLogLevel assigns an individual subsystem logger a new log level.
+	SetLogLevel(subsystemID string, logLevel string)
+
+	// SetLogLevels assigns all subsystem loggers the same new log level.
+	SetLogLevels(logLevel string)
+}
+
+// ParseAndSetDebugLevels attempts to parse the specified debug level and set
+// the levels accordingly on the given logger. An appropriate error is returned
+// if anything is invalid.
+func ParseAndSetDebugLevels(level string, logger LeveledSubLogger) error {
+	// When the specified string doesn't have any delimiters, treat it as
+	// the log level for all subsystems.
+	if !strings.Contains(level, ",") && !strings.Contains(level, "=") {
+		// Validate debug log level.
+		if !validLogLevel(level) {
+			str := "the specified debug level [%v] is invalid"
+			return fmt.Errorf(str, level)
+		}
+
+		// Change the logging level for all subsystems.
+		logger.SetLogLevels(level)
+
+		return nil
+	}
+
+	// Split the specified string into subsystem/level pairs while detecting
+	// issues and update the log levels accordingly.
+	for _, logLevelPair := range strings.Split(level, ",") {
+		if !strings.Contains(logLevelPair, "=") {
+			str := "the specified debug level contains an " +
+				"invalid subsystem/level pair [%v]"
+			return fmt.Errorf(str, logLevelPair)
+		}
+
+		// Extract the specified subsystem and log level.
+		fields := strings.Split(logLevelPair, "=")
+		if len(fields) != 2 {
+			str := "the specified debug level has an invalid " +
+				"format [%v] -- use format subsystem1=level1," +
+				"subsystem2=level2"
+			return fmt.Errorf(str, logLevelPair)
+		}
+		subsysID, logLevel := fields[0], fields[1]
+		subLoggers := logger.SubLoggers()
+
+		// Validate subsystem.
+		if _, exists := subLoggers[subsysID]; !exists {
+			str := "the specified subsystem [%v] is invalid -- " +
+				"supported subsystems are %v"
+			return fmt.Errorf(
+				str, subsysID, logger.SupportedSubsystems(),
+			)
+		}
+
+		// Validate log level.
+		if !validLogLevel(logLevel) {
+			str := "the specified debug level [%v] is invalid"
+			return fmt.Errorf(str, logLevel)
+		}
+
+		logger.SetLogLevel(subsysID, logLevel)
+	}
+
+	return nil
+}
+
+// validLogLevel returns whether or not logLevel is a valid debug log level.
+func validLogLevel(logLevel string) bool {
+	switch logLevel {
+	case "trace":
+		fallthrough
+	case "debug":
+		fallthrough
+	case "info":
+		fallthrough
+	case "warn":
+		fallthrough
+	case "error":
+		fallthrough
+	case "critical":
+		fallthrough
+	case "off":
+		return true
+	}
+	return false
+}