Add --syslog flag to optionally log to syslog on capable platforms

cmd/cmd.go

@@ -31,7 +31,6 @@ var (
 	statsInterval = fs.DurationP("stats", "", time.Minute*1, "Interval between printing stats, e.g 500ms, 60s, 5m. (0 to disable)")
 	dataRateUnit  = fs.StringP("stats-unit", "", "bytes", "Show data rate in stats as either 'bits' or 'bytes'/s")
 	version       bool
-	logFile       = fs.StringP("log-file", "", "", "Log everything to this file")
 	retries       = fs.IntP("retries", "", 3, "Retry operations this many times if they fail")
 )
 
@@ -320,20 +319,8 @@ func StartStats() chan struct{} {
 
 // initConfig is run by cobra after initialising the flags
 func initConfig() {
-	// Log file output
+	// Start the logger
-	if *logFile != "" {
+	fs.InitLogging()
-		f, err := os.OpenFile(*logFile, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0640)
-		if err != nil {
-			log.Fatalf("Failed to open log file: %v", err)
-		}
-		_, err = f.Seek(0, os.SEEK_END)
-		if err != nil {
-			fs.Errorf(nil, "Failed to seek log file to end: %v", err)
-		}
-		log.SetOutput(f)
-		fs.DebugLogger.SetOutput(f)
-		redirectStderr(f)
-	}
 
 	// Load the rest of the config now we have started the logger
 	fs.LoadConfig()

docs/content/docs.md

@@ -502,6 +502,18 @@ then the files will have SUFFIX added on to them.
 
 See `--backup-dir` for more info.
 
+### --syslog ###
+
+On capable OSes (not Windows or Plan9) send all log output to syslog.
+
+This can be useful for running rclone in script or `rclone mount`.
+
+### -syslog-facility string ###
+
+If using `--syslog` this sets the syslog facility (eg `KERN`, `USER`).
+See `man syslog` for a list of possible facilities.  The default
+facility is `DAEMON`.
+
 ### --track-renames ###
 
 By default rclone doesn't not keep track of renamed files, so if you

fs/flags.go

@@ -254,7 +254,7 @@ func setDefaultFromEnv(name string) {
 		if err != nil {
 			log.Fatalf("Invalid value for environment variable %q: %v", key, err)
 		}
-		// log.Printf("Set default for %q from %q to %q (%v)", name, key, newValue, flag.Value)
+		Debugf(nil, "Set default for %q from %q to %q (%v)", name, key, newValue, flag.Value)
 		flag.DefValue = newValue
 	}
 }

fs/log.go

@@ -11,9 +11,17 @@ import (
 // LogLevel describes rclone's logs.  These are a subset of the syslog log levels.
 type LogLevel byte
 
-//go:generate stringer -type=LogLevel
+// Log levels.  These are the syslog levels of which we only use a
-
+// subset.
-// Log levels - a subset of the syslog logs
+//
+//    LOG_EMERG      system is unusable
+//    LOG_ALERT      action must be taken immediately
+//    LOG_CRIT       critical conditions
+//    LOG_ERR        error conditions
+//    LOG_WARNING    warning conditions
+//    LOG_NOTICE     normal, but significant, condition
+//    LOG_INFO       informational message
+//    LOG_DEBUG      debug-level message
 const (
 	LogLevelEmergency LogLevel = iota
 	LogLevelAlert
@@ -25,25 +33,52 @@ const (
 	LogLevelDebug  // Debug level, needs -vv
 )
 
-// Outside world interface
+var logLevelToString = []string{
+	LogLevelEmergency: "EMERGENCY",
+	LogLevelAlert:     "ALERT",
+	LogLevelCritical:  "CRITICAL",
+	LogLevelError:     "ERROR",
+	LogLevelWarning:   "WARNING",
+	LogLevelNotice:    "NOTICE",
+	LogLevelInfo:      "INFO",
+	LogLevelDebug:     "DEBUG",
+}
 
-// DebugLogger - logs to Stdout
+// String turns a LogLevel into a string
-var DebugLogger = log.New(os.Stdout, "", log.LstdFlags)
+func (l LogLevel) String() string {
-
+	if l >= LogLevel(len(logLevelToString)) {
-// makeLog produces a log string from the arguments passed in
+		return fmt.Sprintf("LogLevel(%d)", l)
-func makeLog(o interface{}, text string, args ...interface{}) string {
-	out := fmt.Sprintf(text, args...)
-	if o == nil {
-		return out
 	}
-	return fmt.Sprintf("%v: %s", o, out)
+	return logLevelToString[l]
+}
+
+// Flags
+var (
+	logFile        = StringP("log-file", "", "", "Log everything to this file")
+	useSyslog      = BoolP("syslog", "", false, "Use Syslog for logging")
+	syslogFacility = StringP("syslog-facility", "", "DAEMON", "Facility for syslog, eg KERN,USER,...")
+)
+
+// logPrint sends the text to the logger of level
+var logPrint = func(level LogLevel, text string) {
+	text = fmt.Sprintf("%-6s: %s", level, text)
+	log.Print(text)
+}
+
+// logPrintf produces a log string from the arguments passed in
+func logPrintf(level LogLevel, o interface{}, text string, args ...interface{}) {
+	out := fmt.Sprintf(text, args...)
+	if o != nil {
+		out = fmt.Sprintf("%v: %s", o, out)
+	}
+	logPrint(level, out)
 }
 
 // Errorf writes error log output for this Object or Fs.  It
-// unconditionally logs a message regardless of Config.LogLevel
+// should always be seen by the user.
 func Errorf(o interface{}, text string, args ...interface{}) {
 	if Config.LogLevel >= LogLevelError {
-		log.Print(makeLog(o, text, args...))
+		logPrintf(LogLevelError, o, text, args...)
 	}
 }
 
@@ -54,7 +89,7 @@ func Errorf(o interface{}, text string, args ...interface{}) {
 // out with the -q flag.
 func Logf(o interface{}, text string, args ...interface{}) {
 	if Config.LogLevel >= LogLevelNotice {
-		log.Print(makeLog(o, text, args...))
+		logPrintf(LogLevelNotice, o, text, args...)
 	}
 }
 
@@ -63,7 +98,7 @@ func Logf(o interface{}, text string, args ...interface{}) {
 // appear with the -v flag.
 func Infof(o interface{}, text string, args ...interface{}) {
 	if Config.LogLevel >= LogLevelInfo {
-		DebugLogger.Print(makeLog(o, text, args...))
+		logPrintf(LogLevelInfo, o, text, args...)
 	}
 }
 
@@ -71,6 +106,31 @@ func Infof(o interface{}, text string, args ...interface{}) {
 // debug only.  The user must have to specify -vv to see this.
 func Debugf(o interface{}, text string, args ...interface{}) {
 	if Config.LogLevel >= LogLevelDebug {
-		DebugLogger.Print(makeLog(o, text, args...))
+		logPrintf(LogLevelDebug, o, text, args...)
+	}
+}
+
+// InitLogging start the logging as per the command line flags
+func InitLogging() {
+	// Log file output
+	if *logFile != "" {
+		f, err := os.OpenFile(*logFile, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0640)
+		if err != nil {
+			log.Fatalf("Failed to open log file: %v", err)
+		}
+		_, err = f.Seek(0, os.SEEK_END)
+		if err != nil {
+			Errorf(nil, "Failed to seek log file to end: %v", err)
+		}
+		log.SetOutput(f)
+		redirectStderr(f)
+	}
+
+	// Syslog output
+	if *useSyslog {
+		if *logFile != "" {
+			log.Fatalf("Can't use --syslog and --log-file together")
+		}
+		startSysLog()
 	}
 }

fs/loglevel_string.go

@@ -1,16 +0,0 @@
-// Code generated by "stringer -type=LogLevel"; DO NOT EDIT
-
-package fs
-
-import "fmt"
-
-const _LogLevel_name = "LogLevelEmergencyLogLevelAlertLogLevelCriticalLogLevelErrorLogLevelWarningLogLevelNoticeLogLevelInfoLogLevelDebug"
-
-var _LogLevel_index = [...]uint8{0, 17, 30, 46, 59, 74, 88, 100, 113}
-
-func (i LogLevel) String() string {
-	if i >= LogLevel(len(_LogLevel_index)-1) {
-		return fmt.Sprintf("LogLevel(%d)", i)
-	}
-	return _LogLevel_name[_LogLevel_index[i]:_LogLevel_index[i+1]]
-}

fs/redirect_stderr.go

@@ -2,15 +2,11 @@
 
 // +build !windows,!darwin,!dragonfly,!freebsd,!linux,!nacl,!netbsd,!openbsd
 
-package cmd
+package fs
 
-import (
+import "os"
-	"os"
-
-	"github.com/ncw/rclone/fs"
-)
 
 // redirectStderr to the file passed in
 func redirectStderr(f *os.File) {
-	fs.Errorf(nil, "Can't redirect stderr to file")
+	Errorf(nil, "Can't redirect stderr to file")
 }

fs/redirect_stderr_unix.go

@@ -2,7 +2,7 @@
 
 // +build !windows,!solaris,!plan9
 
-package cmd
+package fs
 
 import (
 	"log"

fs/redirect_stderr_windows.go

@@ -6,7 +6,7 @@
 
 // +build windows
 
-package cmd
+package fs
 
 import (
 	"log"

fs/syslog.go

@@ -0,0 +1,16 @@
+// Syslog interface for non-Unix variants only
+
+// +build windows nacl plan9
+
+package fs
+
+import (
+	"log"
+	"runtime"
+)
+
+// Starts syslog if configured, returns true if it was started
+func startSysLog() bool {
+	log.Fatalf("--syslog not supported on %s platform", runtime.GOOS)
+	return false
+}

fs/syslog_unix.go

@@ -0,0 +1,65 @@
+// Syslog interface for Unix variants only
+
+// +build !windows,!nacl,!plan9
+
+package fs
+
+import (
+	"log"
+	"log/syslog"
+	"os"
+	"path"
+)
+
+var (
+	syslogFacilityMap = map[string]syslog.Priority{
+		"KERN":     syslog.LOG_KERN,
+		"USER":     syslog.LOG_USER,
+		"MAIL":     syslog.LOG_MAIL,
+		"DAEMON":   syslog.LOG_DAEMON,
+		"AUTH":     syslog.LOG_AUTH,
+		"SYSLOG":   syslog.LOG_SYSLOG,
+		"LPR":      syslog.LOG_LPR,
+		"NEWS":     syslog.LOG_NEWS,
+		"UUCP":     syslog.LOG_UUCP,
+		"CRON":     syslog.LOG_CRON,
+		"AUTHPRIV": syslog.LOG_AUTHPRIV,
+		"FTP":      syslog.LOG_FTP,
+	}
+)
+
+// Starts syslog
+func startSysLog() bool {
+	facility, ok := syslogFacilityMap[*syslogFacility]
+	if !ok {
+		log.Fatalf("Unknown syslog facility %q - man syslog for list", *syslogFacility)
+	}
+	Me := path.Base(os.Args[0])
+	w, err := syslog.New(syslog.LOG_NOTICE|facility, Me)
+	if err != nil {
+		log.Fatalf("Failed to start syslog: %v", err)
+	}
+	log.SetFlags(0)
+	log.SetOutput(w)
+	logPrint = func(level LogLevel, text string) {
+		switch level {
+		case LogLevelEmergency:
+			_ = w.Emerg(text)
+		case LogLevelAlert:
+			_ = w.Alert(text)
+		case LogLevelCritical:
+			_ = w.Crit(text)
+		case LogLevelError:
+			_ = w.Err(text)
+		case LogLevelWarning:
+			_ = w.Warning(text)
+		case LogLevelNotice:
+			_ = w.Notice(text)
+		case LogLevelInfo:
+			_ = w.Info(text)
+		case LogLevelDebug:
+			_ = w.Debug(text)
+		}
+	}
+	return true
+}