confighttp.ToServer should be setting ErrorLog

[yurishkuro]

Is your feature request related to a problem? Please describe.

Standard http.Server has a field ErrorLog:

	// ErrorLog specifies an optional logger for errors accepting
	// connections, unexpected behavior from handlers, and
	// underlying FileSystem errors.
	// If nil, logging is done via the log package's standard logger.
	ErrorLog *log.Logger

However, confighttp.ToServer leaves it empty, which will lead to error logs printed using a different logger.

Describe the solution you'd like
In Jaeger we initialize it with a logger backed by Zap:

	errorLog, _ := zap.NewStdLogAt(params.Logger, zapcore.ErrorLevel)
	server.ErrorLog = errorLog

I think confighttp.ToServer() should do the same.

[tarun-kavipurapu]

@yurishkuro hey can i take this up

[yurishkuro]

feel free

[tarun-kavipurapu]

@yurishkuro
I Implemented this in this way is this the correct pattern to Implement or should the pass ErrorLog in ServerConfig Struct
sorry but i am kind a newbie to this

	errHandler func(w http.ResponseWriter, r *http.Request, errorMsg string, statusCode int)
	decoders   map[string]func(body io.ReadCloser) (io.ReadCloser, error)
	errorLog   *log.Logger
}
func WithErrorLogger(logger *log.Logger) ToServerOption {
	return toServerOptionFunc(func(opts *toServerOptions) {
		opts.errorLog = logger
	})
}

[yurishkuro]

there is no need for new options - the ToServer function already receives a logger via telemetry settings. It can just assign ErrorLogger.

[tarun-kavipurapu]

So you mean to say the Error Logger Should always be Zap.logger and the client should not get any option to give his own logger?

[yurishkuro]

yes. It's a bug fix, not a capability.