Merge pull request #30 from dl1998/async-logger

Add async logger

docs/architecture/diagrams/plantuml/class_diagram.plantuml

@@ -227,6 +227,28 @@ package pkg {
             + Critical(message : string, parameters : ...any)
             + Emergency(message : string, parameters : ...any)
         }
+        struct baseAsyncLogger implements baseLoggerInterface {
+            ~ *baseLogger
+            ~ messageQueue : chan logrecord.Interface
+            ~ waitGroup sync.WaitGroup
+            ~ startListeningMessages()
+            + WaitToFinishLogging()
+            + Open(queueSize : int)
+            + Close()
+            + Log(level : level.Level, message : string, parameters : ...any)
+        }
+        interface AsyncLoggerInterface extends Interface {
+            + Interface
+            + WaitToFinishLogging()
+            + Open(queueSize : int)
+            + Close()
+        }
+        struct AsyncLogger implements AsyncLoggerInterface {
+            + *Logger
+            + WaitToFinishLogging()
+            + Open(queueSize : int)
+            + Close()
+        }
         struct Configuration {
             ~ fromLevel : level.Level
             ~ toLevel : level.Level
@@ -243,6 +265,7 @@ package pkg {
             ~ template : string
             ~ init()
             + New(name : string, timeFormat : string) : *Logger
+            + NewAsyncLogger(name : string, timeFormat : string, queueSize : int) : *AsyncLogger
             + WithFromLevel(fromLevel : level.Level) : Option
             + WithToLevel(toLevel : level.Level) : Option
             + WithTemplate(template : string) : Option
@@ -268,7 +291,9 @@ package pkg {
             + Emergency(message : string, parameters : ...any)
         }
 
+        baseAsyncLogger *-- baseLogger
         Logger *-- baseLoggerInterface
+        AsyncLogger *-- Logger
         "<<module>>" ..> Logger : uses
         "<<module>>" ..> Option : uses
         "<<module>>" ..> Configuration : uses

examples/README.md

@@ -2,13 +2,24 @@
 
 This package contains examples how to use logger.
 
+## customasynclogger
+
+Demonstrates how to create a new custom logger for the application.
+
+It creates an async logger with provided queue size that writes messages on the console asynchronously. It also provides
+an example how to wait for all messages to be written.
+
 ## customlogger
 
-Demonstrates how to create a new custom logger for the application. It creates a simple logger that writes messages on the console.
+Demonstrates how to create a new custom logger for the application.
+
+It creates a simple logger that writes messages on the console.
 
 ## customstructuredlogger
 
-Demonstrates how to create a new custom logger for the application. It creates a simple logger that writes messages on the console in structured format.
+Demonstrates how to create a new custom logger for the application.
+
+It creates a simple logger that writes messages on the console in structured format.
 
 ## defaultlogger
 

examples/customasynclogger/main.go

@@ -0,0 +1,29 @@
+// Example that shows how to create and use custom async logger.
+package main
+
+import (
+	"fmt"
+	"github.com/dl1998/go-logging/pkg/common/level"
+	"github.com/dl1998/go-logging/pkg/logger"
+	"github.com/dl1998/go-logging/pkg/logger/formatter"
+	"github.com/dl1998/go-logging/pkg/logger/handler"
+	"time"
+)
+
+func main() {
+	asyncQueueSize := 10
+
+	applicationLogger := logger.NewAsyncLogger("example", time.DateTime, asyncQueueSize)
+
+	applicationFormatter := formatter.New("%(datetime) [%(level)] %(message)")
+	consoleHandler := handler.NewConsoleHandler(level.Debug, level.Null, applicationFormatter)
+	applicationLogger.AddHandler(consoleHandler)
+
+	for index := 0; index < asyncQueueSize; index++ {
+		applicationLogger.Warning("This message will be displayed.")
+	}
+
+	fmt.Println("This will be printed before the last warning log message.")
+
+	applicationLogger.WaitToFinishLogging()
+}

examples/customlogger/main.go

@@ -14,7 +14,7 @@ func main() {
 
 	applicationLogger.Debug("This message will not be displayed, because there are no handlers registered.")
 
-	applicationFormatter := formatter.New("%(isotime) [%(level)] %(message)")
+	applicationFormatter := formatter.New("%(datetime) [%(level)] %(message)")
 	consoleHandler := handler.NewConsoleHandler(level.Debug, level.Null, applicationFormatter)
 	applicationLogger.AddHandler(consoleHandler)
 

examples/logtofile/main.go

@@ -24,7 +24,7 @@ func main() {
 
 	applicationLogger := logger.New("file-logger", time.RFC3339)
 
-	applicationFormatter := formatter.New("%(isotime) [%(level)] %(message)")
+	applicationFormatter := formatter.New("%(datetime) [%(level)] %(message)")
 	fileHandler := handler.NewFileHandler(level.Warning, level.Null, applicationFormatter, fmt.Sprintf("%s/file.log", directory))
 	applicationLogger.AddHandler(fileHandler)
 

pkg/logger/asynclogger.go

@@ -0,0 +1,101 @@
+package logger
+
+import (
+	"github.com/dl1998/go-logging/pkg/common/level"
+	"github.com/dl1998/go-logging/pkg/logger/handler"
+	"github.com/dl1998/go-logging/pkg/logger/logrecord"
+	"sync"
+)
+
+// baseAsyncLogger struct contains basic fields for the async logger.
+type baseAsyncLogger struct {
+	// baseLogger is a base logger.
+	*baseLogger
+	// messageQueue is a channel for the log messages.
+	messageQueue chan logrecord.Interface
+	// waitGroup is a wait group for the async logger messages.
+	waitGroup sync.WaitGroup
+}
+
+// startListeningMessages starts listening for messages in the messageQueue.
+func (logger *baseAsyncLogger) startListeningMessages() {
+	for record := range logger.messageQueue {
+		for _, registeredHandler := range logger.handlers {
+			registeredHandler.Write(record)
+		}
+		logger.waitGroup.Done()
+	}
+}
+
+// WaitToFinishLogging waits for all messages to be logged.
+func (logger *baseAsyncLogger) WaitToFinishLogging() {
+	logger.waitGroup.Wait()
+}
+
+// Open opens the messageQueue with the provided queueSize and starts listening
+// for messages.
+func (logger *baseAsyncLogger) Open(queueSize int) {
+	logger.messageQueue = make(chan logrecord.Interface, queueSize)
+	go logger.startListeningMessages()
+}
+
+// Close closes the messageQueue.
+func (logger *baseAsyncLogger) Close() {
+	close(logger.messageQueue)
+}
+
+// Log logs interpolated message with the provided level.Level.
+func (logger *baseAsyncLogger) Log(level level.Level, message string, parameters ...any) {
+	logger.waitGroup.Add(1)
+	record := logrecord.New(logger.name, level, logger.timeFormat, message, parameters, 3)
+	logger.messageQueue <- record
+}
+
+// AsyncLoggerInterface defines async logger interface.
+type AsyncLoggerInterface interface {
+	Interface
+	WaitToFinishLogging()
+	Open(queueSize int)
+	Close()
+}
+
+// AsyncLogger represents an asynchronous logger.
+type AsyncLogger struct {
+	// Logger is a standard logger.
+	*Logger
+}
+
+// NewAsyncLogger creates a new AsyncLogger with the provided name, timeFormat, and queueSize.
+func NewAsyncLogger(name string, timeFormat string, queueSize int) *AsyncLogger {
+	newBaseLogger := &baseAsyncLogger{
+		baseLogger: &baseLogger{
+			name:       name,
+			timeFormat: timeFormat,
+			handlers:   make([]handler.Interface, 0),
+		},
+		messageQueue: make(chan logrecord.Interface, queueSize),
+		waitGroup:    sync.WaitGroup{},
+	}
+	go newBaseLogger.startListeningMessages()
+	return &AsyncLogger{
+		Logger: &Logger{
+			baseLogger: newBaseLogger,
+		},
+	}
+}
+
+// WaitToFinishLogging waits for all messages to be logged.
+func (logger *AsyncLogger) WaitToFinishLogging() {
+	logger.baseLogger.(*baseAsyncLogger).WaitToFinishLogging()
+}
+
+// Open opens the messageQueue with the provided queueSize and starts listening
+// for messages.
+func (logger *AsyncLogger) Open(queueSize int) {
+	logger.baseLogger.(*baseAsyncLogger).Open(queueSize)
+}
+
+// Close closes the messageQueue.
+func (logger *AsyncLogger) Close() {
+	logger.baseLogger.(*baseAsyncLogger).Close()
+}