how to prevent ERROR messages going to stdout ?

[yonnic]

well i saw no way to set a flag or other option to prevent ERROR messages printing in console.
I would like all logger messages to be only in a file

verbose false and system false did not help

[gmassman]

I'm getting the same behavior.
In my tests I set up logger like so testLogger := logger.Init("Test", false, false, ioutil.Discard), but still ERROR messages go to stdout. I wouldn't mind working on this if someone from the core team gave me some guidance on how to proceed.

EDIT:
After a little digging, I believe logger.go#L97 is causing the issue. This could be resolved by moving the line inside the if verbose {...}, or adding an option for skipping the eLogs = append(eLogs, os.Stderr).

[adjackura]

There's not a simple way to get this functionality and keep the API surface for existing users. In our other loggers we moved to options so we could add features like this, but that would be a breaking change here. We could add options on top of the existing arguments to Init though, right now 'stdout' would be the only option.

[gmassman]

Would it be safe to skip eLogs = append(eLogs, os.Stderr) if the logFile input is ioutil.Discard? The intent is pretty clear that any log data can be thrown away, and this would have a minimum impact on users relying on the existing API.

[dozysun]

I think reset writers can solve this problem and doesn't influence existing users:

func (l *Logger) SetOutput(writers ...io.Writer){    
     logLock.Lock()    
     defer logLock.Unlock()
     l.infoLog.SetOutput(io.MultiWriter(writers...))
     l.warningLog.SetOutput(io.MultiWriter(writers...))
     l.errorLog.SetOutput(io.MultiWriter(writers...))
     l.fatalLog.SetOutput(io.MultiWriter(writers...))
}