Logging FAQ

Level

level - importance - severity
日志级别有两种表示方式：
- SeverityText
- SeverityNumber - Priority
  - 1-100
  - 0-7
Severity, Urgency
Filtering
Actionability
Consistency
Customization
Extensibility

mean	level	syslog	console	go/slog	OpenTelemetry
Emergency	emerg	0,~~panic~~
Alert	alert	1
Critical	crit	2
Fatal	fatal				FATAL, 21-24
Error	error	3,err,~~error~~	✅	8	ERROR, 17-20
Warning	warn	4,warning,~~warn~~	✅	4	WARN, 13-16
Notice	notice	5
Information	info	6	✅	0	INFO, 9-12
Debug	debug	7	✅	-4	DEBUG, 5-8
Trace	trace		✅		TRACE, 1-4

https://opentelemetry.io/docs/specs/otel/logs/
- 0 unspecified
- 每个级别 4 个数字
- 1-4 TRACE
- 5-8 DEBUG
- 9-12 INFO
- 13-16 WARN
- 17-20 ERROR
- 21-24 FATAL
consola
- -Inf silent
- 0 error, fatal
- 1 warn
- 2 log
- 3 info, success, fail, start, ready, box
- 4 debug
- 5 trace
- +Inf verbose
- https://github.com/unjs/consola/blob/main/src/constants.ts
Log4j
- Name - Priority
- OFF 0
- FATAL 100
- ERROR 200
- WARN 300
- INFO 400
- DEBUG 500
- TRACE 600
- ALL Integer.MAX_VALUE
zap
- https://github.com/uber-go/zap/blob/master/zapcore/level.go
- dpanic - 开发模式下 panic - 有点类似于 assert

silent
fatal
error
- panic
- critical
warn
- warning
log
info
- success
- fail
- start
- ready
debug
trace
verbose

/*
Bunyan
 const levels = {
    FATAL: 60,
    ERROR: 50,
    WARN: 40,
    INFO: 30,
    DEBUG: 20,
    TRACE: 10
  }

  Pino
  const levels = {
    fatal: 60,
    error: 50,
    warn: 40,
    info: 30,
    debug: 20,
    trace: 10
  }
Winston
  const levels = {
    error: 0,
    warn: 1,
    info: 2,
    debug: 3
  }
Syslog RFC 3164
0 = Emergency
1 = Alert
2 = Critical
3 = Error
4 = Warning
5 = Notice
6 = Informational
7 = Debug
 */

Level​

Level