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Levelled and structure logger using log package only
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| package logger | |
| import ( | |
| "fmt" | |
| "log" | |
| "os" | |
| "strings" | |
| ) | |
| type Level int | |
| const ( | |
| DEBUG Level = iota | |
| INFO | |
| WARN | |
| ERROR | |
| ) | |
| type Logger struct { | |
| inner *log.Logger | |
| level Level | |
| } | |
| func New(level Level) *Logger { | |
| return &Logger{log.New(os.Stderr, "", log.Ldate|log.Ltime), level} | |
| } | |
| func (l *Logger) log(level Level, label, msg string, kvs []any) { | |
| if level < l.level { | |
| return | |
| } | |
| parts := make([]string, 0, len(kvs)/2) | |
| for i := 0; i+1 < len(kvs); i += 2 { | |
| parts = append(parts, fmt.Sprintf("%v=%v", kvs[i], kvs[i+1])) | |
| } | |
| line := fmt.Sprintf("[%s] %s", label, msg) | |
| if len(parts) > 0 { | |
| line += " " + strings.Join(parts, " ") | |
| } | |
| l.inner.Output(3, line) | |
| } | |
| func (l *Logger) Debug(msg string, kvs ...any) { l.log(DEBUG, "DEBUG", msg, kvs) } | |
| func (l *Logger) Info(msg string, kvs ...any) { l.log(INFO, "INFO", msg, kvs) } | |
| func (l *Logger) Warn(msg string, kvs ...any) { l.log(WARN, "WARN", msg, kvs) } | |
| func (l *Logger) Error(msg string, kvs ...any) { l.log(ERROR, "ERROR", msg, kvs) } |
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