// Package cylogger provides a feature-rich, colored logging library for Go applications. // It offers structured logging with multiple levels, colored output, goroutine tracking, // panic recovery, and object dumping capabilities. // // Key Features: // - Multiple log levels (Error, Warning, Info, Debug, Trace, Dump, Lua) // - Colored terminal output with customizable styling // - Structured logging with fields and context // - Goroutine ID tracking // - Panic recovery and safe goroutine execution // - Object dumping for debugging and testing // - Multiple output destinations (stdout, files) // - Thread-safe operations // // Basic Usage: // // cylogger.Init(cylogger.LevelInfo) // cylogger.Info("Application started") // cylogger.WithField("user", "john").Info("User logged in") // // Advanced Usage: // // logger := cylogger.New(os.Stdout, "", log.LstdFlags) // logger.SetLevel(cylogger.LevelDebug) // logger.WithFields(map[string]interface{}{"service": "api", "version": "1.0"}).Info("Service initialized") package cylogger import ( "bytes" "flag" "fmt" "io" "log" "os" "path/filepath" "runtime" "strconv" "strings" "sync" "time" "github.com/hexops/valast" ) // TODO: Enable turning colors on and off maybe even per stream? var loglevel = flag.String("loglevel", "info", "log level") // LogLevel defines the severity and type of log messages. // Lower values indicate higher priority. Messages are only logged if their level // is less than or equal to the current logger level. type LogLevel int const ( // LevelError is for critical errors that should always be displayed. // These represent serious problems that may cause the application to fail. LevelError LogLevel = iota // LevelWarning is for important warnings that indicate potential issues. // These represent situations that are not errors but may require attention. LevelWarning // LevelInfo is for general informational messages about application flow. // These provide context about what the application is doing. LevelInfo // LevelDebug is for detailed debugging information. // These are useful for diagnosing problems during development. LevelDebug // LevelTrace is for very detailed tracing information. // These provide the most verbose output for deep debugging. LevelTrace // LevelDump is for dumping objects to console for regressive tests. // This level is specifically designed for object inspection and testing. LevelDump // LevelLua is specifically for output from Lua scripts. // This level bypasses normal level filtering and is always shown. LevelLua // LevelPrefix is used internally for styling user prefixes. // This is not a logging level but a style identifier. LevelPrefix ) // LevelStyle defines the visual styling configuration for a log level. // It controls how log messages appear in the terminal with colors and formatting. type LevelStyle struct { // Tag is the text label displayed for this log level (e.g., "ERROR", "INFO") Tag string // TagColor is the ANSI color code for the tag text TagColor string // TagBackgroundColor is the ANSI color code for the tag background TagBackgroundColor string // MessageColor is the ANSI color code for the message text MessageColor string // MessageBackgroundColor is the ANSI color code for the message background MessageBackgroundColor string } // levelStyles maps LogLevel to its display style var levelStyles = map[LogLevel]LevelStyle{ LevelError: { Tag: "ERROR", TagColor: BIRed, // Bold Intense Red TagBackgroundColor: On_White, // White background MessageColor: White, // Bold White text MessageBackgroundColor: On_IRed, // Intense Red background }, LevelWarning: { Tag: "WARNING", TagColor: BIOrange, // Bold Intense Orange TagBackgroundColor: On_White, // White background MessageColor: White, // Bold White text MessageBackgroundColor: On_IOrange, // Intense Orange background }, LevelInfo: { Tag: "INFO", TagColor: BGreen, // Bold Green }, LevelDebug: { Tag: "DEBUG", TagColor: BCyan, // Bold Cyan }, LevelTrace: { Tag: "TRACE", TagColor: BPurple, // Bold Purple }, LevelDump: { Tag: "DUMP", TagColor: BIMagenta, // Bold Intense Magenta TagBackgroundColor: On_White, // White background MessageColor: IMagenta, // White text }, LevelLua: { Tag: "LUA", TagColor: BBlue, // Bold Blue }, LevelPrefix: { Tag: "PREFIX", // Used for coloring the user prefix TagColor: BIGray, // Bold Gray }, } // Logger is a thread-safe, feature-rich logger that supports multiple output destinations, // structured logging, colored output, and various log levels. It can be used both as a // standalone logger or as part of a structured logging system with context fields. type Logger struct { // mu protects all fields from concurrent access mu sync.Mutex // out is the list of output destinations for log messages out []io.Writer // currentLevel determines which log messages are actually written currentLevel LogLevel // prefix is the standard Go log prefix (timestamp, file, etc.) prefix string // userPrefix is a custom user-defined prefix for log messages userPrefix string // flag controls which standard log information is included (timestamp, file, line, etc.) flag int // useColors determines whether ANSI color codes are included in output useColors bool // callerOffset adjusts the stack depth for caller information callerOffset int // defaultFields are key-value pairs included in all log messages from this logger defaultFields map[string]interface{} // showGoroutine determines whether goroutine ID is included in log messages showGoroutine bool } var ( // Default is the global logger instance used by package-level functions. // It is automatically initialized when first used if not explicitly set. Default *Logger // defaultLogLevel is the default log level used when initializing the logger defaultLogLevel = LevelInfo // initMutex protects the initialization of the Default logger from race conditions initMutex sync.Mutex ) // ParseLevel converts a string representation of a log level to the corresponding LogLevel. // It accepts case-insensitive strings like "error", "warning", "info", "debug", "trace", "dump", and "lua". // If the string is not recognized, it returns the default log level (LevelInfo). func ParseLevel(levelStr string) LogLevel { switch strings.ToUpper(levelStr) { case "ERROR": return LevelError case "WARNING", "WARN": return LevelWarning case "INFO": return LevelInfo case "DEBUG": return LevelDebug case "TRACE": return LevelTrace case "DUMP": return LevelDump case "LUA": return LevelLua default: return defaultLogLevel } } // String returns the string representation of the log level. // It returns the tag name (e.g., "ERROR", "INFO") or a formatted representation for unknown levels. func (l LogLevel) String() string { if name, ok := levelStyles[l]; ok { return name.Tag } return fmt.Sprintf("Level(%d)", l) } // New creates a new Logger instance with the specified output destination, prefix, and flags. // The logger is initialized with default settings: LevelInfo log level, colors enabled, // goroutine tracking enabled, and no default fields. func New(out io.Writer, prefix string, flag int) *Logger { return &Logger{ out: []io.Writer{out}, currentLevel: defaultLogLevel, prefix: prefix, userPrefix: "", flag: flag, useColors: true, callerOffset: 0, defaultFields: make(map[string]interface{}), showGoroutine: true, } } // InitFlag initializes the default logger using the loglevel flag value. // This library defines a "loglevel" command-line flag that accepts values like "error", "warning", "info", "debug", "trace", "dump", or "lua". // This function should be called after flag.Parse() to use command-line log level configuration. // Example usage: // // flag.Parse() // cylogger.InitFlag() // // Now the logger level is set based on the -loglevel flag func InitFlag() { level := ParseLevel(*loglevel) Init(level) } // Init initializes the Default logger with the specified log level. // If the Default logger is already initialized, it only updates the log level. // This function is thread-safe and can be called multiple times. func Init(level LogLevel) { initMutex.Lock() defer initMutex.Unlock() if Default == nil { Default = New(os.Stdout, "", log.Lmicroseconds|log.Lshortfile) } Default.SetLevel(level) } // SetLevel sets the current log level for the logger. // Only messages with a level less than or equal to this level will be logged. // This method is thread-safe. func (l *Logger) SetLevel(level LogLevel) { l.mu.Lock() defer l.mu.Unlock() l.currentLevel = level } // GetLevel returns the current log level of the logger. // This method is thread-safe. func (l *Logger) GetLevel() LogLevel { l.mu.Lock() defer l.mu.Unlock() return l.currentLevel } // SetCallerOffset sets the caller offset for correct file and line reporting. // This is useful when the logger is wrapped in helper functions to ensure // the correct caller information is displayed. func (l *Logger) SetCallerOffset(offset int) { l.mu.Lock() defer l.mu.Unlock() l.callerOffset = offset } // SetShowGoroutine sets whether to include goroutine ID in log messages. // This is useful for debugging concurrent applications where you need to track // which goroutine generated each log message. func (l *Logger) SetShowGoroutine(show bool) { l.mu.Lock() defer l.mu.Unlock() l.showGoroutine = show } // ShowGoroutine returns whether goroutine ID is included in log messages. // This method is thread-safe. func (l *Logger) ShowGoroutine() bool { l.mu.Lock() defer l.mu.Unlock() return l.showGoroutine } // WithField creates a new logger instance with an additional field in its context. // The field will be included in all log messages from the returned logger, appearing as key=value pairs appended to the message. // This is useful for structured logging where you want to add context to a group of log messages. // Example: // // logger := cylogger.WithField("user", "john") // logger.Info("User logged in") // Output: "User logged in user=john" // logger.Error("Login failed") // Output: "Login failed user=john" // // This is particularly useful for scoped logging in functions or loops where you want to track context // without continuously logging an ID or identifier. func (l *Logger) WithField(key string, value interface{}) *Logger { newLogger := &Logger{ out: append([]io.Writer(nil), l.out...), currentLevel: l.currentLevel, prefix: l.prefix, userPrefix: l.userPrefix, flag: l.flag, useColors: l.useColors, callerOffset: l.callerOffset, defaultFields: make(map[string]interface{}), showGoroutine: l.showGoroutine, } // Copy existing fields for k, v := range l.defaultFields { newLogger.defaultFields[k] = v } // Add new field newLogger.defaultFields[key] = value return newLogger } // WithFields creates a new logger instance with multiple additional fields in its context. // All fields will be included in all log messages from the returned logger, appearing as key=value pairs appended to the message. // This is useful for structured logging where you want to add multiple context fields. // Example: // // fields := map[string]interface{}{"user": "john", "role": "admin", "session": "abc123"} // logger := cylogger.WithFields(fields) // logger.Info("Processing request") // Output: "Processing request user=john role=admin session=abc123" // // This is particularly useful for scoped logging where you need to track multiple pieces of context // without repeatedly logging them in each message. func (l *Logger) WithFields(fields map[string]interface{}) *Logger { newLogger := &Logger{ out: append([]io.Writer(nil), l.out...), currentLevel: l.currentLevel, prefix: l.prefix, userPrefix: l.userPrefix, flag: l.flag, useColors: l.useColors, callerOffset: l.callerOffset, defaultFields: make(map[string]interface{}), showGoroutine: l.showGoroutine, } // Copy existing fields for k, v := range l.defaultFields { newLogger.defaultFields[k] = v } // Add new fields for k, v := range fields { newLogger.defaultFields[k] = v } return newLogger } // WithPrefix creates a new logger instance with an additional user prefix. // The prefix will be displayed in all log messages from the returned logger, appearing as [prefix] before the message. // This is useful for adding context or module identification to log messages. // Example: // // logger := cylogger.WithPrefix("AUTH") // logger.Info("User authenticated") // Output: "[AUTH] User authenticated" // logger.Error("Login failed") // Output: "[AUTH] Login failed" // // This is particularly useful for scoped logging in functions, loops, or modules where you want to know // what the log line refers to without continuously logging an ID or identifier. // Unlike WithField which appends fields to the end, WithPrefix prepends the prefix to the beginning. func (l *Logger) WithPrefix(prefix string) *Logger { if Default == nil { Init(defaultLogLevel) } if l == nil { l = Default } newLogger := &Logger{ out: append([]io.Writer(nil), l.out...), currentLevel: l.currentLevel, prefix: l.prefix, userPrefix: strings.TrimSpace(l.userPrefix + " " + prefix), flag: l.flag, useColors: l.useColors, callerOffset: l.callerOffset, defaultFields: make(map[string]interface{}), showGoroutine: l.showGoroutine, } // Copy existing fields for k, v := range l.defaultFields { newLogger.defaultFields[k] = v } return newLogger } // ToFile creates a new logger instance that writes to both the original outputs and a file. // The file is opened in append mode and will be created if it doesn't exist. // This is useful for logging to both console and file simultaneously. // Example: // // logger := cylogger.New(os.Stdout, "", log.LstdFlags) // fileLogger := logger.ToFile("app.log") // fileLogger.Info("This will appear in both console and app.log") // // The file is opened with os.O_CREATE|os.O_WRONLY|os.O_APPEND flags, so it will be created if it doesn't exist // and new log entries will be appended to the end of the file. func (l *Logger) ToFile(filename string) *Logger { file, err := os.OpenFile(filename, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644) if err != nil { log.Fatal(err) } if Default == nil { Init(defaultLogLevel) } if l == nil { l = Default } newLogger := &Logger{ out: append([]io.Writer(nil), l.out...), currentLevel: l.currentLevel, prefix: l.prefix, userPrefix: l.userPrefix, flag: l.flag, useColors: l.useColors, callerOffset: l.callerOffset, defaultFields: make(map[string]interface{}), showGoroutine: l.showGoroutine, } // Copy existing fields for k, v := range l.defaultFields { newLogger.defaultFields[k] = v } // Append the new file writer newLogger.out = append(newLogger.out, file) return newLogger } // GetGoroutineID extracts the current goroutine ID from the runtime stack. // This is used internally by the logger to include goroutine information in log messages. func GetGoroutineID() string { buf := make([]byte, 64) n := runtime.Stack(buf, false) // Format of first line is "goroutine N [state]:" // We only need the N part buf = buf[:n] idField := bytes.Fields(bytes.Split(buf, []byte{':'})[0])[1] return string(idField) } // formatMessage formats a log message with level, time, file, and line information func (l *Logger) formatMessage(level LogLevel, format string, args ...interface{}) string { var msg string if len(args) > 0 { msg = fmt.Sprintf(format, args...) } else { msg = format } // Format default fields if any var fields string if len(l.defaultFields) > 0 { var pairs []string for k, v := range l.defaultFields { pairs = append(pairs, fmt.Sprintf("%s=%v", k, v)) } fields = " " + strings.Join(pairs, " ") } var tagFgColor, tagBgColor, messageBgColor string useSpecialFormatting := false // Flag for levels with custom message background/foreground if l.useColors { // Check if a message background color is defined for this level style if levelStyles[level].MessageBackgroundColor != "" { useSpecialFormatting = true // Retrieve all style components from the map tagFgColor = levelStyles[level].TagColor // Assign directly tagBgColor = levelStyles[level].TagBackgroundColor // messageFgColor = levelStyles[level].MessageColor messageBgColor = levelStyles[level].MessageBackgroundColor } else { // For other levels (INFO, DEBUG, etc.), only TagColor is guaranteed tagFgColor = levelStyles[level].TagColor // Use the defined tag color // tagBgColor, messageFgColor, messageBgColor remain empty (use terminal defaults) } } var caller string if l.flag&log.Lshortfile != 0 || l.flag&log.Llongfile != 0 { var file string var line int var ok bool // Start at a reasonable depth and scan up to 10 frames for depth := 4; depth < 15; depth++ { _, file, line, ok = runtime.Caller(depth) if !ok { break } // Check if the caller is within this logger package itself if !strings.Contains(file, "main.go") && !strings.Contains(file, "colors.go") { break } } if !ok { file = "???" line = 0 } if l.flag&log.Lshortfile != 0 { file = filepath.Base(file) } // Caller string - no background color applied here caller = fmt.Sprintf("%-25s ", file+":"+strconv.Itoa(line)) } // Format the timestamp with fixed width - no background color applied here var timeStr string if l.flag&(log.Ldate|log.Ltime|log.Lmicroseconds) != 0 { t := time.Now() if l.flag&log.Ldate != 0 { timeStr += fmt.Sprintf("%04d/%02d/%02d ", t.Year(), t.Month(), t.Day()) } if l.flag&(log.Ltime|log.Lmicroseconds) != 0 { timeStr += fmt.Sprintf("%02d:%02d:%02d", t.Hour(), t.Minute(), t.Second()) if l.flag&log.Lmicroseconds != 0 { timeStr += fmt.Sprintf(".%06d", t.Nanosecond()/1000) } } timeStr = fmt.Sprintf("%-15s ", timeStr) } // Add goroutine ID if enabled, with fixed width - no background color applied here var goroutineStr string if l.showGoroutine { goroutineID := GetGoroutineID() goroutineStr = fmt.Sprintf("[g:%-4s] ", goroutineID) } // --- Level Tag Formatting and Padding --- levelStr := levelStyles[level].Tag visibleTagContent := fmt.Sprintf("[%s]", levelStr) visibleTagLen := len(visibleTagContent) paddingWidth := 10 // Target width for the level column (tag + padding) numSpaces := paddingWidth - visibleTagLen if numSpaces < 0 { numSpaces = 1 // Ensure at least one space } padding := strings.Repeat(" ", numSpaces) var levelTagFormatted string if useSpecialFormatting { // ERROR/WARNING: Tag has specific background and foreground levelTagFormatted = fmt.Sprintf("%s%s%s%s", tagBgColor, tagFgColor, visibleTagContent, Reset) } else { // Other levels: Tag has standard foreground color only levelTagFormatted = fmt.Sprintf("%s%s%s", tagFgColor, visibleTagContent, Reset) } levelColumn := levelTagFormatted + padding // Combine formatted tag and padding // --- User Prefix Formatting (part of message content for coloring purposes) --- userPrefixStr := "" if l.userPrefix != "" { // Format the string part here, colors applied later if needed userPrefixStr = fmt.Sprintf("[%s] ", l.userPrefix) } // --- Message Content --- messageContent := fmt.Sprintf("%s%s", msg, fields) // --- Assemble Final String --- var finalMsg strings.Builder // Part 1: Timestamp, Caller, Goroutine ID (always default colors) finalMsg.WriteString(l.prefix) finalMsg.WriteString(timeStr) finalMsg.WriteString(caller) finalMsg.WriteString(goroutineStr) // Part 2: Level Column (already formatted with tag colors and padding) finalMsg.WriteString(levelColumn) // Part 3: User Prefix + Message Content (apply special formatting if needed) if useSpecialFormatting { // ERROR/WARNING: Apply message background and foreground to User Prefix + Message finalMsg.WriteString(messageBgColor) // finalMsg.WriteString(messageFgColor) // This doesn't work...? For some reason? finalMsg.WriteString(userPrefixStr) // Write user prefix inside the colored block finalMsg.WriteString(messageContent) finalMsg.WriteString(Reset) } else { // Other levels: User Prefix and Message content use default colors // Apply specific color to user prefix if it exists if l.userPrefix != "" { prefixColor := levelStyles[LevelPrefix].TagColor finalMsg.WriteString(fmt.Sprintf("%s%s%s", prefixColor, userPrefixStr, Reset)) } // No else needed, if userPrefix is empty, userPrefixStr is "" anyway finalMsg.WriteString(messageContent) // Append message with default colors } return finalMsg.String() } // log logs a message at the specified level func (l *Logger) log(level LogLevel, format string, args ...interface{}) { // Always show LUA level logs regardless of the current log level if level != LevelLua && level > l.currentLevel { return } l.mu.Lock() defer l.mu.Unlock() // Get formatted message with potential background color msg := l.formatMessage(level, format, args...) for _, w := range l.out { fmt.Fprintln(w, msg) } } // Error logs an error message at LevelError. // Error messages are always displayed regardless of the current log level. func (l *Logger) Error(format string, args ...interface{}) { l.log(LevelError, format, args...) } // Warning logs a warning message at LevelWarning. // Warning messages indicate potential issues that should be noted. func (l *Logger) Warning(format string, args ...interface{}) { l.log(LevelWarning, format, args...) } // Info logs an informational message at LevelInfo. // Info messages provide general information about application flow. func (l *Logger) Info(format string, args ...interface{}) { l.log(LevelInfo, format, args...) } // Debug logs a debug message at LevelDebug. // Debug messages provide detailed information useful for diagnosing problems. func (l *Logger) Debug(format string, args ...interface{}) { l.log(LevelDebug, format, args...) } // Trace logs a trace message at LevelTrace. // Trace messages provide the most detailed information for deep debugging. func (l *Logger) Trace(format string, args ...interface{}) { l.log(LevelTrace, format, args...) } // Dump logs objects using valast for regressive tests at LevelDump. // This is useful for debugging and testing where you need to inspect object state. // The objects are formatted using valast for readable output. // Example: // // type User struct { Name string; Age int } // user := User{Name: "John", Age: 30} // logger.Dump("User data", user) // // Output: "User data:\nUser{Name: \"John\", Age: 30}" // // This is particularly useful for regressive testing where you need to capture // the exact state of objects for comparison or debugging purposes. func (l *Logger) Dump(message string, objects ...interface{}) { if len(objects) == 0 { l.log(LevelDump, message) return } var dumpContent strings.Builder dumpContent.WriteString(message) dumpContent.WriteString(":\n") for i, obj := range objects { if i > 0 { dumpContent.WriteString("\n") } dumpContent.WriteString(valast.String(obj)) } l.log(LevelDump, dumpContent.String()) } // Lua logs a Lua message at LevelLua. // Lua messages are always displayed regardless of the current log level. // This is specifically designed for output from Lua scripts. func (l *Logger) Lua(format string, args ...interface{}) { l.log(LevelLua, format, args...) } // Global log functions that use DefaultLogger // Error logs an error message using the default logger. // This is a convenience function that uses the global Default logger instance. func Error(format string, args ...interface{}) { if Default == nil { Init(defaultLogLevel) } Default.Error(format, args...) } // Warning logs a warning message using the default logger. // This is a convenience function that uses the global Default logger instance. func Warning(format string, args ...interface{}) { if Default == nil { Init(defaultLogLevel) } Default.Warning(format, args...) } // Info logs an informational message using the default logger. // This is a convenience function that uses the global Default logger instance. func Info(format string, args ...interface{}) { if Default == nil { Init(defaultLogLevel) } Default.Info(format, args...) } // Debug logs a debug message using the default logger. // This is a convenience function that uses the global Default logger instance. func Debug(format string, args ...interface{}) { if Default == nil { Init(defaultLogLevel) } Default.Debug(format, args...) } // Trace logs a trace message using the default logger. // This is a convenience function that uses the global Default logger instance. func Trace(format string, args ...interface{}) { if Default == nil { Init(defaultLogLevel) } Default.Trace(format, args...) } // Dump logs objects using valast for regressive tests using the default logger. // This is a convenience function that uses the global Default logger instance. func Dump(message string, objects ...interface{}) { if Default == nil { Init(defaultLogLevel) } Default.Dump(message, objects...) } // Lua logs a Lua message using the default logger. // This is a convenience function that uses the global Default logger instance. func Lua(format string, args ...interface{}) { if Default == nil { Init(defaultLogLevel) } Default.Lua(format, args...) } // LogPanic logs a panic error and its stack trace using the default logger. // This is useful for logging panics that have been recovered elsewhere. // The function logs the panic value and full stack trace. func LogPanic(r interface{}) { if Default == nil { Init(defaultLogLevel) } stack := make([]byte, 4096) n := runtime.Stack(stack, false) Default.Error("PANIC: %v\n%s", r, stack[:n]) } // SetLevel sets the log level for the default logger. // This is a convenience function that uses the global Default logger instance. func SetLevel(level LogLevel) { if Default == nil { Init(level) return } Default.SetLevel(level) } // GetLevel gets the log level for the default logger. // This is a convenience function that uses the global Default logger instance. func GetLevel() LogLevel { if Default == nil { Init(defaultLogLevel) } return Default.GetLevel() } // WithField returns a new logger with the field added to the default logger's context. // This is a convenience function that uses the global Default logger instance. func WithField(key string, value interface{}) *Logger { if Default == nil { Init(defaultLogLevel) } return Default.WithField(key, value) } // WithFields returns a new logger with the fields added to the default logger's context. // This is a convenience function that uses the global Default logger instance. func WithFields(fields map[string]interface{}) *Logger { if Default == nil { Init(defaultLogLevel) } return Default.WithFields(fields) } // SetShowGoroutine enables or disables goroutine ID display in the default logger. // This is a convenience function that uses the global Default logger instance. func SetShowGoroutine(show bool) { if Default == nil { Init(defaultLogLevel) } Default.SetShowGoroutine(show) } // ShowGoroutine returns whether goroutine ID is included in default logger's messages. // This is a convenience function that uses the global Default logger instance. func ShowGoroutine() bool { if Default == nil { Init(defaultLogLevel) } return Default.ShowGoroutine() } // NoStdout creates a new logger instance that excludes stdout from its output destinations. // This is useful when you want to log only to files or other destinations, not to the console. // The original logger's stdout output is filtered out while keeping all other output destinations. func (l *Logger) NoStdout() *Logger { if Default == nil { Init(defaultLogLevel) } if l == nil { l = Default } newLogger := &Logger{ out: nil, currentLevel: l.currentLevel, prefix: l.prefix, userPrefix: l.userPrefix, flag: l.flag, useColors: l.useColors, callerOffset: l.callerOffset, defaultFields: make(map[string]interface{}), showGoroutine: l.showGoroutine, } // Copy existing fields for k, v := range l.defaultFields { newLogger.defaultFields[k] = v } // Keep all writers except stdout for _, w := range l.out { if w == os.Stdout { continue } newLogger.out = append(newLogger.out, w) } return newLogger } func main() { Init(LevelDebug) // Test basic logging Debug("This is a debug message") Info("This is an info message") Warning("This is a warning message") Error("This is an error message") // Test logging with fields logger := WithField("user", "testuser") logger.Info("User logged in") // Test logging with multiple fields fields := map[string]interface{}{ "user": "testuser", "role": "admin", "id": 12345, } WithFields(fields).Info("User details") // Test error logging with fields WithField("error", "connection failed").Error("Database error") logger.WithPrefix("CUSTOM").Info("This is a message with a custom prefix") // Test goroutine ID display SetShowGoroutine(true) Info("This message should show goroutine ID") // Test different log levels SetLevel(LevelInfo) Debug("This debug message should not appear") Info("This info message should appear") // Test with custom prefix WithField("prefix", "custom").Info("Message with custom prefix") Lua("This is a Lua message") // Test Dump functionality SetLevel(LevelDump) // Set level to show dump messages type ProjectData struct { Title string Name string Data string Commits string } type Project struct { Id int64 Data *ProjectData } p := Project{ Id: 1, Data: &ProjectData{ Title: "Test", Name: "Mihai", Data: "Some data", Commits: "Test Message", }, } // Test single object dump Dump("FooBar called", p) // Test multiple object dump Dump("Multiple objects", p, fields, "string value", 42) }