zap logging with 1) customized config and 2) lumberjack - go

Question

I'm trying to build a customized zap logger with 1) customized *zap.Config and 2) lumberjack, but can't find proper example to apply both configurations.
Since config.Build does not accept WriteSync as an input. Do you know how to achieve this?
func genBaseLoggerZap() Logger {
ex, err := os.Executable()
if err != nil {
Fatalf("Failed to get os.Executable, err: %v", err)
}
zlManager.outputPath = path.Join(filepath.Dir(ex), zlManager.outputPath)
// Want to add sync here..
zapcore.AddSync(&lumberjack.Logger{
Filename: zlManager.outputPath + "123",
MaxSize: 500,
MaxBackups: 10,
MaxAge: 28,
})
return genLoggerZap(BaseLogger, genDefaultConfig())
}
// genLoggerZap creates a zapLogger with given ModuleID and Config.
func genLoggerZap(mi ModuleID, cfg *zap.Config) Logger {
logger, err := cfg.Build()
if err != nil {
Fatalf("Failed to generate zap logger, err: %v", err)
}
newLogger := &zapLogger{mi, cfg, logger.Sugar()}
newLogger.register()
return newLogger
}

Answer 1

You can add custom log destinations using the zap.RegisterSink function and the Config.OutputPaths field. RegisterSink maps URL schemes to Sink constructors, and OutputPaths configures log destinations (encoded as URLs).
Conveniently, *lumberjack.Logger implements almost all of the zap.Sink interface already. Only the Sync method is missing, which can be easily added with a thin wrapper type.
package main
import (
"net/url"
"go.uber.org/zap"
lumberjack "gopkg.in/natefinch/lumberjack.v2"
)
type lumberjackSink struct {
*lumberjack.Logger
}
// Sync implements zap.Sink. The remaining methods are implemented
// by the embedded *lumberjack.Logger.
func (lumberjackSink) Sync() error { return nil }
func main() {
zap.RegisterSink("lumberjack", func(u *url.URL) (zap.Sink, error) {
return lumberjackSink{
Logger: &lumberjack.Logger{
Filename: u.Opaque,
// Use query parameters or hardcoded values for remaining
// fields.
},
}, nil
})
config := zap.NewProductionConfig()
// Add a URL with the "lumberjack" scheme.
config.OutputPaths = append(config.OutputPaths, "lumberjack:foo.log")
log, _ := config.Build()
log.Info("test", zap.String("foo", "bar"))
}