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authorobscuren <geffobscura@gmail.com>2014-10-31 19:56:05 +0800
committerobscuren <geffobscura@gmail.com>2014-10-31 19:56:05 +0800
commitb1c247231b11f313ca0eedff75ea563926d23f68 (patch)
tree48b2136cb65e69cb79ffac80f3cc3fdf9dba1cc8 /logger/loggers.go
parentfd9da72536b73351bbcdc1e9dbbbb8c0e4bfb21b (diff)
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ethlog => logger
Diffstat (limited to 'logger/loggers.go')
-rw-r--r--logger/loggers.go248
1 files changed, 248 insertions, 0 deletions
diff --git a/logger/loggers.go b/logger/loggers.go
new file mode 100644
index 000000000..1bf7bfa0e
--- /dev/null
+++ b/logger/loggers.go
@@ -0,0 +1,248 @@
+/*
+Package logger implements a multi-output leveled logger.
+
+Other packages use tagged logger to send log messages to shared
+(process-wide) logging engine. The shared logging engine dispatches to
+multiple log systems. The log level can be set separately per log
+system.
+
+Logging is asynchronous and does not block the caller. Message
+formatting is performed by the caller goroutine to avoid incorrect
+logging of mutable state.
+*/
+package logger
+
+import (
+ "fmt"
+ "io"
+ "log"
+ "os"
+ "sync"
+ "sync/atomic"
+)
+
+// LogSystem is implemented by log output devices.
+// All methods can be called concurrently from multiple goroutines.
+type LogSystem interface {
+ GetLogLevel() LogLevel
+ SetLogLevel(i LogLevel)
+ LogPrint(LogLevel, string)
+}
+
+type message struct {
+ level LogLevel
+ msg string
+}
+
+type LogLevel uint8
+
+const (
+ // Standard log levels
+ Silence LogLevel = iota
+ ErrorLevel
+ WarnLevel
+ InfoLevel
+ DebugLevel
+ DebugDetailLevel
+)
+
+var (
+ logMessageC = make(chan message)
+ addSystemC = make(chan LogSystem)
+ flushC = make(chan chan struct{})
+ resetC = make(chan chan struct{})
+)
+
+func init() {
+ go dispatchLoop()
+}
+
+// each system can buffer this many messages before
+// blocking incoming log messages.
+const sysBufferSize = 500
+
+func dispatchLoop() {
+ var (
+ systems []LogSystem
+ systemIn []chan message
+ systemWG sync.WaitGroup
+ )
+ bootSystem := func(sys LogSystem) {
+ in := make(chan message, sysBufferSize)
+ systemIn = append(systemIn, in)
+ systemWG.Add(1)
+ go sysLoop(sys, in, &systemWG)
+ }
+
+ for {
+ select {
+ case msg := <-logMessageC:
+ for _, c := range systemIn {
+ c <- msg
+ }
+
+ case sys := <-addSystemC:
+ systems = append(systems, sys)
+ bootSystem(sys)
+
+ case waiter := <-resetC:
+ // reset means terminate all systems
+ for _, c := range systemIn {
+ close(c)
+ }
+ systems = nil
+ systemIn = nil
+ systemWG.Wait()
+ close(waiter)
+
+ case waiter := <-flushC:
+ // flush means reboot all systems
+ for _, c := range systemIn {
+ close(c)
+ }
+ systemIn = nil
+ systemWG.Wait()
+ for _, sys := range systems {
+ bootSystem(sys)
+ }
+ close(waiter)
+ }
+ }
+}
+
+func sysLoop(sys LogSystem, in <-chan message, wg *sync.WaitGroup) {
+ for msg := range in {
+ if sys.GetLogLevel() >= msg.level {
+ sys.LogPrint(msg.level, msg.msg)
+ }
+ }
+ wg.Done()
+}
+
+// Reset removes all active log systems.
+// It blocks until all current messages have been delivered.
+func Reset() {
+ waiter := make(chan struct{})
+ resetC <- waiter
+ <-waiter
+}
+
+// Flush waits until all current log messages have been dispatched to
+// the active log systems.
+func Flush() {
+ waiter := make(chan struct{})
+ flushC <- waiter
+ <-waiter
+}
+
+// AddLogSystem starts printing messages to the given LogSystem.
+func AddLogSystem(sys LogSystem) {
+ addSystemC <- sys
+}
+
+// A Logger prints messages prefixed by a given tag. It provides named
+// Printf and Println style methods for all loglevels. Each ethereum
+// component should have its own logger with a unique prefix.
+type Logger struct {
+ tag string
+}
+
+func NewLogger(tag string) *Logger {
+ return &Logger{"[" + tag + "] "}
+}
+
+func (logger *Logger) sendln(level LogLevel, v ...interface{}) {
+ logMessageC <- message{level, logger.tag + fmt.Sprintln(v...)}
+}
+
+func (logger *Logger) sendf(level LogLevel, format string, v ...interface{}) {
+ logMessageC <- message{level, logger.tag + fmt.Sprintf(format, v...)}
+}
+
+// Errorln writes a message with ErrorLevel.
+func (logger *Logger) Errorln(v ...interface{}) {
+ logger.sendln(ErrorLevel, v...)
+}
+
+// Warnln writes a message with WarnLevel.
+func (logger *Logger) Warnln(v ...interface{}) {
+ logger.sendln(WarnLevel, v...)
+}
+
+// Infoln writes a message with InfoLevel.
+func (logger *Logger) Infoln(v ...interface{}) {
+ logger.sendln(InfoLevel, v...)
+}
+
+// Debugln writes a message with DebugLevel.
+func (logger *Logger) Debugln(v ...interface{}) {
+ logger.sendln(DebugLevel, v...)
+}
+
+// DebugDetailln writes a message with DebugDetailLevel.
+func (logger *Logger) DebugDetailln(v ...interface{}) {
+ logger.sendln(DebugDetailLevel, v...)
+}
+
+// Errorf writes a message with ErrorLevel.
+func (logger *Logger) Errorf(format string, v ...interface{}) {
+ logger.sendf(ErrorLevel, format, v...)
+}
+
+// Warnf writes a message with WarnLevel.
+func (logger *Logger) Warnf(format string, v ...interface{}) {
+ logger.sendf(WarnLevel, format, v...)
+}
+
+// Infof writes a message with InfoLevel.
+func (logger *Logger) Infof(format string, v ...interface{}) {
+ logger.sendf(InfoLevel, format, v...)
+}
+
+// Debugf writes a message with DebugLevel.
+func (logger *Logger) Debugf(format string, v ...interface{}) {
+ logger.sendf(DebugLevel, format, v...)
+}
+
+// DebugDetailf writes a message with DebugDetailLevel.
+func (logger *Logger) DebugDetailf(format string, v ...interface{}) {
+ logger.sendf(DebugDetailLevel, format, v...)
+}
+
+// Fatalln writes a message with ErrorLevel and exits the program.
+func (logger *Logger) Fatalln(v ...interface{}) {
+ logger.sendln(ErrorLevel, v...)
+ Flush()
+ os.Exit(0)
+}
+
+// Fatalf writes a message with ErrorLevel and exits the program.
+func (logger *Logger) Fatalf(format string, v ...interface{}) {
+ logger.sendf(ErrorLevel, format, v...)
+ Flush()
+ os.Exit(0)
+}
+
+// NewStdLogSystem creates a LogSystem that prints to the given writer.
+// The flag values are defined package log.
+func NewStdLogSystem(writer io.Writer, flags int, level LogLevel) LogSystem {
+ logger := log.New(writer, "", flags)
+ return &stdLogSystem{logger, uint32(level)}
+}
+
+type stdLogSystem struct {
+ logger *log.Logger
+ level uint32
+}
+
+func (t *stdLogSystem) LogPrint(level LogLevel, msg string) {
+ t.logger.Print(msg)
+}
+
+func (t *stdLogSystem) SetLogLevel(i LogLevel) {
+ atomic.StoreUint32(&t.level, uint32(i))
+}
+
+func (t *stdLogSystem) GetLogLevel() LogLevel {
+ return LogLevel(atomic.LoadUint32(&t.level))
+}