Installation

// New constructs a new Logger writing to the provided io.Writer.
// It applies the default Options. If the provided writer is nil, it defaults
// to standard error.
func New(w io.Writer) *Logger

// NewWithOptions constructs a new Logger using the specified Options.
// It provides full control over the Logger's behavior, including asynchronous
// writing, formatting, and field extraction.
func NewWithOptions(w io.Writer, o Options) *Logger

type Options struct {
    // Level sets the minimum logging priority
    Level Level
    
    // BufferSize defines the capacity of the internal ring buffer
    // for asynchronous loggers. Must be a power of 2. Defaults to 8192.
    BufferSize int
    
    // OverflowStrategy dictates behavior when the buffer fills up
    // Defaults to OverflowSync
    OverflowStrategy OverflowStrategy
    
    // ReportTimestamp includes a timestamp in every log entry
    ReportTimestamp bool
    
    // TimeFormat specifies the layout string for timestamps
    // Defaults to "2006/01/02 15:04:05"
    TimeFormat string
    
    // ReportCaller includes the calling file and line number
    // Note: Enabling this incurs a significant performance penalty
    ReportCaller bool
    
    // ReportStacktrace includes a full stack trace for ErrorLevel or higher
    // Note: Enabling this incurs a significant performance penalty on errors
    ReportStacktrace bool
    
    // Prefix prepends a static string to every log message
    Prefix string
    
    // Fields attaches default key-value pairs to every log entry
    Fields []any
    
    // Formatter dictates serialization (TextFormatter or JSONFormatter)
    // Defaults to TextFormatter
    Formatter Formatter
    
    // Async enables the background worker with lock-free ring buffer
    Async bool
}