Hide sensitive fields in Uber Zap go

Question

Is there any way in which I can hide logging sensitive fields while using ubergo zap.

Will appreciate if somebody can show an example

Answer 1

You can make those fields custom type and implement Stringer interface for them printing ****. For example:

type X string

func (x X) String() string {
    return "***"
}
func main() {
    x := X("aaaaa")
    log.Infow("msg", "x", x)
}

will print msg {"x": "***"}.

Or you can implement your own version of Encoder where you would filter fields by name or their type Interface in EncodeEntry(ent Entry, fields []Field) function. You can take one of the two existing encoders - console or json - as a base. For example:

package main

import (
    "go.uber.org/zap"
    "go.uber.org/zap/buffer"
    "go.uber.org/zap/zapcore"
)

type MyEncoder struct {
    zapcore.Encoder
}

func (m *MyEncoder) EncodeEntry(entry zapcore.Entry, fields []zapcore.Field) (*buffer.Buffer, error) {
    filtered := make([]zapcore.Field, 0, len(fields))
    for _, field := range fields {
        if field.Key == "skip" || field.Type == zapcore.Int64Type {
            continue
        }
        filtered = append(filtered, field)
    }
    return m.Encoder.EncodeEntry(entry, filtered)
}

func main() {
    _ = zap.RegisterEncoder("mine", func(config zapcore.EncoderConfig) (zapcore.Encoder, error) {
        encoder := zapcore.NewConsoleEncoder(config)
        return &MyEncoder{encoder}, nil
    })
    config := zap.NewDevelopmentConfig()
    config.Encoding = "mine"
    log, _ := config.Build()
    sugar := log.Sugar()
    sugar.Infow("Some message", "skip", "skipped", "notskip", "present", "alsoskipping", int64(1))
}

This will print

2022-08-24T13:25:54.368+0200    INFO    testl/main.go:33        Some message    {"notskip": "present"}