Question: Rate Limiting ?

[midnightexigent]

Consider the following use case

zap.RedirectStdLog(aZapLogger)

where the std logger will be highly verbose. Since levels don't apply, all the logs will be written. Sampling is no good either since the messages will be different.

Ideally I would like to write something like this

zap.RedirectStdLog(aZapLogger.WithOption(someRateLimitingOption))

Basically saying: "I don't want more than N logs per M seconds"

Does zap provide some sort of primitive to accomplish this, that I missed while reading the docs ?

[midnightexigent]

answering my own question:

I ended up implementing a zapcore.Core using the rate package

func main(){
	zap.RedirectStdLog(logger.WithOptions(zap.WrapCore(func(c zapcore.Core) zapcore.Core {
		return &rateZapCore{
			Core:    c,
			limiter: rate.NewLimiter(rate.Every(time.Second), 5),
		}
	})))
}

type rateZapCore struct {
	zapcore.Core
	limiter *rate.Limiter
}

func (rzc *rateZapCore) Check(e zapcore.Entry, ce *zapcore.CheckedEntry) *zapcore.CheckedEntry {
	if rzc.limiter.Allow() {
		return rzc.Core.Check(e, ce)
	}
	return ce
}

[prashantv]

The sampler is the closest related feature, but as you mentioned, it doesn't help with the messages are variable, as it's used to throttle specific message/level combinations.

The sampler could be extended to accept a custom hash function, but what you're using seems like a good simple option.