How Can I Customize Error Logging in Go\'s net/http Package?

Logging Errors in Custom Format with net/http

In net/http, errors can be logged using the Server.ErrorLog field. To log errors in a custom format, you can replace the default logger with your own implementation.

Custom Logging Implementation

To create a custom logger, define a type that implements the io.Writer interface, as seen in the following example:

type CustomLogger struct {
    writer io.Writer
}

func (l *CustomLogger) Write(p []byte) (n int, err error) {
    // Implement custom logging logic here
}

Using Custom Logger in net/http

Once you have your custom logger, you can set it as the ErrorLog for the http.Server:

server := &http.Server{
    Addr:       ":8080",
    Handler:    myHandler,
    ErrorLog: &CustomLogger{writer: os.Stderr},
}

Using Zap Logger for net/http Error Logging

For errors to be written in the same format as Zap, you need to implement a serverJsonWriter type that forwards the error message to the Zap logger. Here's how:

type serverJsonWriter struct {
    fw *fwdToZapWriter
}

func (w serverJsonWriter) Write(p []byte) (n int, err error) {
    w.fw.logger.Errorw(string(p))
    return len(p), nil
}

Where fwdToZapWriter is:

type fwdToZapWriter struct {
    logger *zap.SugaredLogger
}

func (fw *fwdToZapWriter) Write(p []byte) (n int, err error) {
    fw.logger.Errorw(string(p))
    return len(p), nil
}

You can then use the serverJsonWriter type in your server:

server := &http.Server{
    Addr:       ":8080",
    Handler:    myHandler,
    ErrorLog: log.New(&serverJsonWriter{fw: &fwdToZapWriter{logger: myZapLogger}}, "", 0),
}

By implementing these steps, you can log net/http errors in your own custom format using your Zap logger.

The above is the detailed content of How Can I Customize Error Logging in Go\'s net/http Package?. For more information, please follow other related articles on the PHP Chinese website!