general improvements (#2)

* Replaced strutil.Md5 with crypto/md5 and encoding/hex to reduce dependency and potential allocations.

* Move to improved logging library.

* fixup! Move to improved logging library.

logging/logger.go

@@ -0,0 +1,204 @@
+package libpack_logger
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/goccy/go-json"
+)
+
+const (
+	_ = iota
+	LEVEL_DEBUG
+	LEVEL_INFO
+	LEVEL_WARN
+	LEVEL_ERROR
+	LEVEL_FATAL
+)
+
+var LevelNames = [...]string{
+	"none",
+	"debug",
+	"info",
+	"warn",
+	"error",
+	"fatal",
+}
+
+const (
+	defaultFormat     = time.RFC3339
+	defaultMinLevel   = LEVEL_INFO
+	defaultShowCaller = false
+)
+
+var defaultOutput = os.Stdout
+
+type Logger struct {
+	output      io.Writer
+	format      string
+	minLogLevel int
+	showCaller  bool
+}
+
+type LogMessage struct {
+	output  io.Writer
+	Pairs   map[string]any
+	Message string
+}
+
+func (m *LogMessage) String() string {
+	return m.Message
+}
+
+var fieldNames = map[string]string{
+	"timestamp": "timestamp",
+	"level":     "level",
+	"message":   "message",
+}
+
+func New() *Logger {
+	return &Logger{
+		format:      defaultFormat,
+		minLogLevel: defaultMinLevel,
+		output:      defaultOutput,
+		showCaller:  defaultShowCaller,
+	}
+}
+
+func (l *Logger) SetOutput(output io.Writer) *Logger {
+	l.output = output
+	return l
+}
+
+var bufferPool = sync.Pool{
+	New: func() any {
+		return new(bytes.Buffer)
+	},
+}
+
+var defaultPairs = make(map[string]any)
+
+func GetLogLevel(level string) int {
+	for i, name := range LevelNames {
+		if name == strings.ToLower(level) {
+			return i
+		}
+	}
+	return defaultMinLevel
+}
+
+func (l *Logger) log(level int, m *LogMessage) {
+	if m.Pairs == nil {
+		m.Pairs = defaultPairs
+	}
+
+	m.Pairs[fieldNames["timestamp"]] = time.Now().Format(l.format)
+	m.Pairs[fieldNames["level"]] = LevelNames[level]
+	m.Pairs[fieldNames["message"]] = m.Message
+
+	if l.showCaller {
+		m.Pairs["caller"] = getCaller()
+	}
+
+	buffer := bufferPool.Get().(*bytes.Buffer)
+	defer bufferPool.Put(buffer)
+	buffer.Reset()
+
+	var encoder = json.NewEncoder(buffer)
+	err := encoder.Encode(m.Pairs)
+	if err != nil {
+		fmt.Println("Error marshalling log message:", err)
+		return
+	}
+
+	// if not running in test - use stderr and stdout, otherwise - use logger's output setting
+	if flag.Lookup("test.v") != nil {
+		m.output = os.Stdout
+		if level >= LEVEL_ERROR {
+			m.output = os.Stderr
+		}
+	}
+
+	// Use logger's output setting instead of os.Stdout or os.Stderr
+	l.output.Write(buffer.Bytes())
+}
+
+func (l *Logger) Debug(m *LogMessage) {
+	if l.shouldLog(LEVEL_DEBUG) {
+		l.log(LEVEL_DEBUG, m)
+	}
+}
+
+func (l *Logger) Info(m *LogMessage) {
+	if l.shouldLog(LEVEL_INFO) {
+		l.log(LEVEL_INFO, m)
+	}
+}
+
+func (l *Logger) Warn(m *LogMessage) {
+	if l.shouldLog(LEVEL_WARN) {
+		l.log(LEVEL_WARN, m)
+	}
+}
+
+func (l *Logger) Warning(m *LogMessage) {
+	l.Warn(m)
+}
+
+func (l *Logger) Error(m *LogMessage) {
+	if l.shouldLog(LEVEL_ERROR) {
+		l.log(LEVEL_ERROR, m)
+	}
+}
+
+func (l *Logger) Fatal(m *LogMessage) {
+	if l.shouldLog(LEVEL_FATAL) {
+		l.log(LEVEL_FATAL, m)
+	}
+}
+
+func (l *Logger) Critical(m *LogMessage) {
+	l.Fatal(m)
+	os.Exit(1)
+}
+
+func (l *Logger) shouldLog(level int) bool {
+	return level >= l.minLogLevel
+}
+
+func (l *Logger) SetFormat(format string) *Logger {
+	l.format = format
+	return l
+}
+
+func (l *Logger) SetMinLogLevel(level int) *Logger {
+	l.minLogLevel = level
+	return l
+}
+
+func (l *Logger) SetFieldName(field, name string) *Logger {
+	fieldNames[field] = name
+	return l
+}
+
+func (l *Logger) SetShowCaller(show bool) *Logger {
+	l.showCaller = show
+	return l
+}
+
+func getCaller() string {
+	_, file, line, ok := runtime.Caller(3)
+	if !ok {
+		return "unknown:0"
+	}
+	file = filepath.Base(file)
+	return fmt.Sprintf("%s:%d", file, line)
+}