From 8e9cc3697944c3e568186a5c23ac729f6eb4a1f4 Mon Sep 17 00:00:00 2001 From: zelig Date: Mon, 23 Jun 2014 12:49:04 +0100 Subject: [PATCH] refactor logging. Details: - packages use tagged logger sending log messages to shared (process-wide) logging engine - log writers (interface ethlog.LogSystem) can be added to the logging engine by wrappers/guis/clients - shared logging engine dispatching to multiple log systems - log level can be set separately per log system - async logging thread: logging IO does not block main thread - log messages are synchronously stringified to avoid incorrectly logging of changed states - README.md - loggers_test --- ethlog/README.md | 58 +++++++++++++ ethlog/loggers.go | 179 +++++++++++++++++++++++++++++++++++++++++ ethlog/loggers_test.go | 115 ++++++++++++++++++++++++++ 3 files changed, 352 insertions(+) create mode 100644 ethlog/README.md create mode 100644 ethlog/loggers.go create mode 100644 ethlog/loggers_test.go diff --git a/ethlog/README.md b/ethlog/README.md new file mode 100644 index 000000000..f8818d98e --- /dev/null +++ b/ethlog/README.md @@ -0,0 +1,58 @@ +## Features + +- packages use tagged logger sending log messages to shared (process-wide) logging engine +- log writers (interface ethlog.LogSystem) can be added to the logging engine by wrappers/guis/clients +- shared logging engine dispatching to multiple log systems +- log level can be set separately per log system +- async logging thread: logging IO does not block main thread +- log messages are synchronously stringified to avoid incorrectly logging of changed states + +## Usage + +In an ethereum component package: + + import "github.com/ethereum/eth-go/ethlog" + + // package-wide logger using tag + var logger = ethlog.NewLogger("TAG") + + logger.Infoln("this is info") # > [TAG] This is info + +Ethereum wrappers should register log systems conforming to ethlog.LogSystem + + import "github.com/ethereum/eth-go/ethlog" + + type CustomLogWriter struct { + logLevel ethlog.LogLevel + } + + func (t *TestLogSystem) SetLogLevel(i LogLevel) { + t.level = i + } + + func (t *TestLogSystem) GetLogLevel() LogLevel { + return t.level + } + + func (c *CustomLogWriter) Printf(format string, v...interface{}) { + //.... + } + + func (c *CustomLogWriter) Println(v...interface{}) { + //.... + } + + ethlog.AddLogWriter(&CustomLogWriter{}) + +ethlog also provides constructors for that wrap io.Writers into a standard logger with a settable level: + + filename := "test.log" + file, _ := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, os.ModePerm) + fileLogSystem := NewStdLogSystem(file, 0, WarnLevel) + AddLogSystem(fileLogSystem) + stdOutLogSystem := NewStdLogSystem(os.Stdout, 0, WarnLevel) + AddLogSystem(stdOutLogSystem) + + + + diff --git a/ethlog/loggers.go b/ethlog/loggers.go new file mode 100644 index 000000000..e656ffbe5 --- /dev/null +++ b/ethlog/loggers.go @@ -0,0 +1,179 @@ +package ethlog + +import ( + "fmt" + "sync" + "log" + "io" + "os" +) + +type LogSystem interface { + GetLogLevel() LogLevel + SetLogLevel(i LogLevel) + Println(v ...interface{}) + Printf(format string, v ...interface{}) +} + +type logMessage struct { + LogLevel LogLevel + format bool + msg string +} + +func newPrintlnLogMessage(level LogLevel, tag string, v...interface{}) *logMessage { + return &logMessage{level, false, fmt.Sprintf("[%s] %s", tag, fmt.Sprint(v...))} +} + +func newPrintfLogMessage(level LogLevel, tag string, format string, v...interface{}) *logMessage { + return &logMessage{level, true, fmt.Sprintf("[%s] %s", tag, fmt.Sprintf(format, v...))} +} + +func (msg *logMessage) send(logger LogSystem) { + if msg.format { + logger.Printf(msg.msg) + } else { + logger.Println(msg.msg) + } +} + +var logMessages chan(*logMessage) +var logSystems []LogSystem +var drained = true + +type LogLevel uint8 + +const ( + Silence LogLevel = iota + ErrorLevel + WarnLevel + InfoLevel + DebugLevel +) + +// log messages are dispatched to log writers +func start() { + for { + select { + case msg := <- logMessages: + for _, logSystem := range logSystems { + if logSystem.GetLogLevel() >= msg.LogLevel { + msg.send(logSystem) + } + } + default: + drained = true + } + } +} + +// waits until log messages are drained (dispatched to log writers) +func Flush() { + for !drained {} +} + +type Logger struct { + tag string +} + +func NewLogger(tag string) *Logger { + return &Logger{tag} +} + +func AddLogSystem(logSystem LogSystem) { + var mutex = &sync.Mutex{} + mutex.Lock() + defer mutex.Unlock() + if logSystems == nil { + logMessages = make(chan *logMessage) + go start() + } + logSystems = append(logSystems, logSystem) +} + +func (logger *Logger) sendln(level LogLevel, v...interface{}) { + if logMessages != nil { + msg := newPrintlnLogMessage(level, logger.tag, v...) + drained = false + logMessages <- msg + } +} + +func (logger *Logger) sendf(level LogLevel, format string, v...interface{}) { + if logMessages != nil { + msg := newPrintfLogMessage(level, logger.tag, format, v...) + drained = false + logMessages <- msg + } +} + +func (logger *Logger) Errorln(v...interface{}) { + logger.sendln(ErrorLevel, v...) +} + +func (logger *Logger) Warnln(v...interface{}) { + logger.sendln(WarnLevel, v...) +} + +func (logger *Logger) Infoln(v...interface{}) { + logger.sendln(InfoLevel, v...) +} + +func (logger *Logger) Debugln(v...interface{}) { + logger.sendln(DebugLevel, v...) +} + +func (logger *Logger) Errorf(format string, v...interface{}) { + logger.sendf(ErrorLevel, format, v...) +} + +func (logger *Logger) Warnf(format string, v...interface{}) { + logger.sendf(WarnLevel, format, v...) +} + +func (logger *Logger) Infof(format string, v...interface{}) { + logger.sendf(InfoLevel, format, v...) +} + +func (logger *Logger) Debugf(format string, v...interface{}) { + logger.sendf(DebugLevel, format, v...) +} + +func (logger *Logger) Fatalln (v...interface{}) { + logger.sendln(ErrorLevel, v...) + Flush() + os.Exit(0) +} + +func (logger *Logger) Fatalf (format string, v...interface{}) { + logger.sendf(ErrorLevel, format, v...) + Flush() + os.Exit(0) +} + +type StdLogSystem struct { + logger *log.Logger + level LogLevel +} + +func (t *StdLogSystem) Println(v ...interface{}) { + t.logger.Println(v...) +} + +func (t *StdLogSystem) Printf(format string, v ...interface{}) { + t.logger.Printf(format, v...) +} + +func (t *StdLogSystem) SetLogLevel(i LogLevel) { + t.level = i +} + +func (t *StdLogSystem) GetLogLevel() LogLevel { + return t.level +} + +func NewStdLogSystem(writer io.Writer, flags int, level LogLevel) *StdLogSystem { + logger := log.New(writer, "", flags) + return &StdLogSystem{logger, level} +} + diff --git a/ethlog/loggers_test.go b/ethlog/loggers_test.go new file mode 100644 index 000000000..c33082012 --- /dev/null +++ b/ethlog/loggers_test.go @@ -0,0 +1,115 @@ +package ethlog + +import ( + "testing" + "fmt" + "io/ioutil" + "os" +) + +type TestLogSystem struct { + Output string + level LogLevel +} + +func (t *TestLogSystem) Println(v ...interface{}) { + t.Output += fmt.Sprintln(v...) +} + +func (t *TestLogSystem) Printf(format string, v ...interface{}) { + t.Output += fmt.Sprintf(format, v...) +} + +func (t *TestLogSystem) SetLogLevel(i LogLevel) { + t.level = i +} + +func (t *TestLogSystem) GetLogLevel() LogLevel { + return t.level +} + +func quote(s string) string { + return fmt.Sprintf("'%s'", s) +} + +func TestLoggerPrintln(t *testing.T) { + logger := NewLogger("TEST") + testLogSystem := &TestLogSystem{level: WarnLevel} + AddLogSystem(testLogSystem) + logger.Errorln("error") + logger.Warnln("warn") + logger.Infoln("info") + logger.Debugln("debug") + Flush() + output := testLogSystem.Output + fmt.Println(quote(output)) + if output != "[TEST] error\n[TEST] warn\n" { + t.Error("Expected logger output '[TEST] error\\n[TEST] warn\\n', got ", quote(testLogSystem.Output)) + } +} + +func TestLoggerPrintf(t *testing.T) { + logger := NewLogger("TEST") + testLogSystem := &TestLogSystem{level: WarnLevel} + AddLogSystem(testLogSystem) + logger.Errorf("error to %v\n", *testLogSystem) + logger.Warnf("warn") + logger.Infof("info") + logger.Debugf("debug") + Flush() + output := testLogSystem.Output + fmt.Println(quote(output)) + if output != "[TEST] error to { 2}\n[TEST] warn" { + t.Error("Expected logger output '[TEST] error to { 2}\\n[TEST] warn', got ", quote(testLogSystem.Output)) + } +} + +func TestMultipleLogSystems(t *testing.T) { + logger := NewLogger("TEST") + testLogSystem0 := &TestLogSystem{level: ErrorLevel} + testLogSystem1 := &TestLogSystem{level: WarnLevel} + AddLogSystem(testLogSystem0) + AddLogSystem(testLogSystem1) + logger.Errorln("error") + logger.Warnln("warn") + Flush() + output0 := testLogSystem0.Output + output1 := testLogSystem1.Output + if output0 != "[TEST] error\n" { + t.Error("Expected logger 0 output '[TEST] error\\n', got ", quote(testLogSystem0.Output)) + } + if output1 != "[TEST] error\n[TEST] warn\n" { + t.Error("Expected logger 1 output '[TEST] error\\n[TEST] warn\\n', got ", quote(testLogSystem1.Output)) + } +} + +func TestFileLogSystem(t *testing.T) { + logger := NewLogger("TEST") + filename := "test.log" + file, _ := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, os.ModePerm) + testLogSystem := NewStdLogSystem(file, 0, WarnLevel) + AddLogSystem(testLogSystem) + logger.Errorf("error to %s\n", filename) + logger.Warnln("warn") + Flush() + contents, _ := ioutil.ReadFile(filename) + output := string(contents) + fmt.Println(quote(output)) + if output != "[TEST] error to test.log\n[TEST] warn\n" { + t.Error("Expected contents of file 'test.log': '[TEST] error to test.log\\n[TEST] warn\\n', got ", quote(output)) + } else { + os.Remove(filename) + } +} + +func TestNoLogSystem(t *testing.T) { + logger := NewLogger("TEST") + logger.Warnln("warn") + Flush() +} + + + + + +