Iterating zapcore.EntryCaller

[ducknificient]

Not sure if this a Q&A, but i think it contains a lot of discussions. I have this runtime.calller code

	fmt.Printf("ERROR\n%s:\n", msg)
	var pcs [10]uintptr
	n := runtime.Callers(1, pcs[:])
	iter := runtime.CallersFrames(pcs[:n])
	for {
		f, more := iter.Next()
		fmt.Printf("  %s %s:%d\n", f.Function, f.File, f.Line)
		if !more {
			break
		}
	}

// example print
ERROR
User. error get model. 
:
  example-project/logger.(*EcommLogger).Error /home/user/Projects/example-project/logger/ecomlogger.go:43
  example-project/response.(*GinResponse).Error /home/user/Projects/example-project/response/gin.go:18
  example-project/controller.(*DefaultController).User /home/user/Projects/example-project/controller/UserController.go:120
  github.com/gin-gonic/gin.(*Context).Next /home/user/go/pkg/mod/github.com/gin-gonic/gin@v1.8.2/context.go:173
  github.com/gin-gonic/gin.CustomRecoveryWithWriter.func1 /home/user/go/pkg/mod/github.com/gin-gonic/gin@v1.8.2/recovery.go:101
  github.com/gin-gonic/gin.(*Context).Next /home/user/go/pkg/mod/github.com/gin-gonic/gin@v1.8.2/context.go:173
  github.com/gin-gonic/gin.LoggerWithConfig.func1 /home/user/go/pkg/mod/github.com/gin-gonic/gin@v1.8.2/logger.go:240
  github.com/gin-gonic/gin.(*Context).Next /home/user/go/pkg/mod/github.com/gin-gonic/gin@v1.8.2/context.go:173
  github.com/gin-gonic/gin.(*Engine).handleHTTPRequest /home/user/go/pkg/mod/github.com/gin-gonic/gin@v1.8.2/gin.go:616
  github.com/gin-gonic/gin.(*Engine).ServeHTTP /home/user/go/pkg/mod/github.com/gin-gonic/gin@v1.8.2/gin.go:572

the code print complete caller information. Can i achieve same result using zap ? my log already shown caller, but it's only main. AFAIK the only know to shown caller is by using AddCallerSkip(), but this is not flexible because we need to hardcode it

// initialize the JSON encoding config
	encoderConfig := map[string]string{
		"levelEncoder": "lowercase",
		"levelKey":     "level",
		"timeKey":      "date",
		"timeEncoder":  "iso8601",
		"callerKey":    "caller",
		"messageKey":   "message",
	}
	data, _ := json.Marshal(encoderConfig)

	var encCfg zapcore.EncoderConfig
	if err := json.Unmarshal(data, &encCfg); err != nil {
		panic(err)
	}
	encCfg.EncodeTime = SyslogTimeEncoder
	encCfg.EncodeCaller = MyCaller
	
	zap.New(core, zap.WithCaller(true))

{"level":"info","date":"2023-05-11 09:55:46","caller":"gitlogger.go:107","message":"App listening on localhost:8090"}

[abhinav]

@ducknificient I think you're looking for the AddStacktrace option. It'll print a stack trace for all log messages at and above a certain level.

Note that capturing a stacktrace isn't cheap, so you should only do it for log levels where it's important to have a stack trace: error and above.