How can I overriding the default logger (with logrus or pick your prefered logging library)

[bsergean]

Hi there,

It looks like this commit #271 allowed users to override the client logging.

Here is an example, from the cmd/torrent. -> https://github.com/anacrolix/torrent/blob/master/cmd/torrent/main.go#L321

    if flags.Quiet {
        clientConfig.Logger = log.Discard
    }

This Discard object is a global thing, defined as: https://github.com/anacrolix/log/blob/master/global.go#L14

var (
    Default = Logger{StreamLogger{
        W:   os.Stderr,
        Fmt: LineFormatter,
    }}
    Discard = Logger{StreamLogger{
        W:   ioutil.Discard,
        Fmt: func(Msg) []byte { return nil },
    }}
)

A stream logger is this:

type StreamLogger struct {
    W   io.Writer
    Fmt ByteFormatter
}

func (me StreamLogger) Log(msg Msg) {
    me.W.Write(me.Fmt(msg.Skip(1)))
}

My application is using logrus, and I would like to capture logs and emit them with logrus. So I guess I just need to implement a Log function that takes a msg and print it (with logrus ?). I'll try that.

func (me StreamLogger) Log(msg Msg) {
    me.W.Write(me.Fmt(msg.Skip(1)))
}

[bsergean]

I figured it out, here's what I did:

Calling the thing:

package mypackage_name
...
clientConfig := torrent.NewDefaultClientConfig()
clientConfig.Logger = GetTorrentLogger()

Override logic

// Override torrent log library with logrus
// See https://github.com/anacrolix/torrent/discussions/551

package mypackage_name

import (
	torrentlog "github.com/anacrolix/log"
	log "github.com/sirupsen/logrus"
)

type LogRusAdapterLogger struct{}

func (l LogRusAdapterLogger) Log(msg torrentlog.Msg) {
	if level, ok := msg.GetLevel(); ok {
		// A "DEBUG" is available, we ignore it as it's very noisy, but we should expose it
		switch level.LogString() {
		case "INFO":
			log.Info("⛲ " + msg.Text())
		case "WARN":
			log.Warn("⛲ " + msg.Text())
		case "ERROR":
			log.Error("⛲ " + msg.Text())
		case "CRIT":
			log.Error("⛲ " + msg.Text()) // no logrus.Critical, report this as an error
		case "FATAL":
			log.Error("⛲ " + msg.Text()) // not sure what to do, also map to an error
		}
	}
}

func GetTorrentLogger() torrentlog.Logger {
	return torrentlog.Logger{LogRusAdapterLogger{}}
}

[anacrolix]

You might match against the level values rather than their String, for example log.Level. Additionally the silly package name convention for anacrolix/log is analog, if you care to use that. :)

[anacrolix]

Thanks for contributing that. What do you think of the interface? I'm not especially happy with anacrolix/log, it "bubbles" up log messages in a Context-like chain, but it means that filtering doesn't occur for some time, and there's a fair bit of allocation prior to hitting a filter. Additionally the filters can exist anywhere in the chain, rather than in a single place. It's very flexible, but not practical I think.

[bsergean]

I haven’t thought too much about the interface, as long as I can capture the logs it’s fine for me at this point. I’ll use analog it sounds better. I tried using log.Level (the ‘int’) but I was getting some odd errors while the ’string interface worked.

…

On Aug 29, 2021, at 6:55 PM, Matt Joiner ***@***.***> wrote: You might match against the level values rather than their String, for example log.Level. Additionally the silly package name convention for anacrolix/log is analog, if you care to use that. :) — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#551 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AC2O6ULR4EJEWCWRLIMBOB3T7LQIXANCNFSM5C34V5RQ>. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[skinner12]

I've tried but I get this error:

./main.go:39:21: msg.GetLevel undefined (type "github.com/anacrolix/log".Msg has no field or method GetLevel) ./main.go:57:46: implicit assignment of unexported field 'loggerCore' in "github.com/anacrolix/log".Logger literal ./main.go:57:46: cannot use LogRusAdapterLogger{} (type LogRusAdapterLogger) as type "github.com/anacrolix/log".loggerCore in field value

[anacrolix]

Sorry this will have changed. There was an optimization to check levels without traversing a chain of message context, part of that is that Level is no longer part of the Msg. If it's needed to adapt to other loggers, I could make some changes to pass that through to the formatter.