Cannot log with verbosity > 2

[byatesrae]

When logging at a verbosity > 2 no log messages appear, despite configuring zerolog's minimum accepted level.

I can see logging is short circuited here but I'm not sure why given logr's philosophy seems to imply we choose verbosity based on the applications needs.

package main

import (
	"os"

	"github.com/go-logr/zerologr"
	"github.com/rs/zerolog"
)

func main() {
	zLogger := zerolog.New(os.Stderr)
	zLogger = zLogger.Level(-10)
	zerolog.SetGlobalLevel(-10)

	zLogger.WithLevel(-1).Msg("zLogger -1") // trace
	zLogger.WithLevel(-2).Msg("zLogger -2") // less than trace

	logger := zerologr.New(&zLogger)
	logger.V(2).Info("logger v2")
	logger.V(3).Info("logger v3")
}

Go playground.

Expected output:

{"level":"trace","message":"zLogger -1"}
{"level":"-2","message":"zLogger -2"}
{"level":"trace","v":2,"message":"logger v2"}
{"level":"-2","v":3,"message":"logger v3"}

Actual output:

{"level":"trace","message":"zLogger -1"}
{"level":"-2","message":"zLogger -2"}
{"level":"trace","v":2,"message":"logger v2"}

[hn8]

@byatesrae When using with logr, it is preferrable to avoid calling zerolog.SetGlobalLevel() and use logr.V() instead, so it is safe to use many packages depending on logr. Currently, logr.V() only supports level addition.
https://github.com/go-logr/logr/blob/master/logr.go#L286-L290

[byatesrae]

Thanks @hn8, use of zerolog.SetGlobalLevel() aside how might we log with a verbosity > 2 using logr.V()? From my example I'm using logr.V(2) & logr.V(3) yet no log entry is created when using logr.V(3).

Here's a simplified example:

package main

import (
	"os"

	"github.com/go-logr/zerologr"
	"github.com/rs/zerolog"
)

func main() {
	zLogger := zerolog.New(os.Stderr)
	logger := zerologr.New(&zLogger)

	logger.V(2).Info("logger v2")
	logger.V(3).Info("logger v3")
	logger.V(4).Info("logger v4")
	logger.V(5).Info("logger v5")
}

Go Playground

Expected output:

{"level":"trace","v":2,"message":"logger v2"}
{"level":"-1","v":3,"message":"logger v3"}
{"level":"-2","v":4,"message":"logger v4"}
{"level":"-3","v":5,"message":"logger v5"}

Actual output:

{"level":"trace","v":2,"message":"logger v2"}

[hn8]

@byatesrae zerologr's log level range is limited by underlying implementation of zerolog and logr. zerolog only supports these levels: https://github.com/rs/zerolog#leveled-logging. And logr's philosophy removes warn/fatal/panic. So there are only 3 available logr levels: 0 for info, 1 for debug, 2 for trace and separate error level.

[byatesrae]

@hn8 I think I see where you're coming from. Although, it may just be me but it doesn't seem obvious from zerologr's README.md that only verbosity up to 2 is supported.

Out of curiosity, given the logr philosophy on logging is that only info (with verbosity) and error are needed... why not have zerologr only log at zerolog's info & error levels? Verbosity could still be a seperate structured log field when logging at info.

[ajanata]

@byatesrae When using with logr, it is preferrable to avoid calling zerolog.SetGlobalLevel() and use logr.V() instead, so it is safe to use many packages depending on logr. Currently, logr.V() only supports level addition. https://github.com/go-logr/logr/blob/master/logr.go#L286-L290

Our project uses zerolog as the primary logger, and a library we're using uses logr instead. We want to keep all configuration in zerolog, however we are unable to get debug logs out of the library because of this limitation. What is the suggested workaround in this case?

[tonglil]

@ajanata you can still get Zerolog to print debug level logs: https://go.dev/play/p/aoJrlyE494C

[tonglil]

I will make a PR to document that Zerolog is limited to printing up to V(2) verbosity.

[hn8]

@ajanata In zerolog, using levels more verbose than TraceLevel is an undocumented feature. Would you please share what value you pass into zerolog.SetGlobalLevel() and logr.V()? Or do you pass in zerolog.Logger with different level in zelologr.New()?

[hn8]

@tonglil undocumented zerolog levels do not support LevelSampler and LevelHook, and likely never will since they are struct. zapr may be the better choice than zerologr if higher verbosity is needed.

[thockin]

The whole point of https://github.com/rs/zerolog/pull/350/files was to allow higher V levels. If zerologr can't make that work, it's not really a very useful logr implementation, IMO.

[hn8]

It is possible but not enabled by default in new PR. Explained here #25 (comment)

[ajanata]

@ajanata In zerolog, using levels more verbose than TraceLevel is an undocumented feature. Would you please share what value you pass into zerolog.SetGlobalLevel() and logr.V()? Or do you pass in zerolog.Logger with different level in zelologr.New()?

Apologies, I suppose I should open a bug with opentelemetry-go, since they use V(5) for debug. We are using the standard debug level in zerolog.

[hn8]

@ajanata You can now use SetMaxV to adjust global level of Zerolog in zerologr v1.2.3.