Announcing gnet v2.7.0

The gnet v2.7.0 is officially released!

In this release, most of the core internal packages used by gnet are now available outside of gnet!

Take netpoll package as an example:

Package netpoll provides a portable event-driven interface for network I/O.

The underlying facility of event notification is OS-specific:

epoll on Linux
kqueue on *BSD/Darwin

With the help of the netpoll package, you can easily build your own high-performance event-driven network applications based on epoll/kqueue.

The Poller represents the event notification facility whose backend is epoll or kqueue. The OpenPoller function creates a new Poller instance:

	poller, err := netpoll.OpenPoller()
	if err != nil {
		// handle error
	}

	defer poller.Close()

	addr, err := net.ResolveTCPAddr("tcp", "127.0.0.1:9090")
	if err != nil {
		// handle error
	}
	c, err := net.DialTCP("tcp", nil, addr)
	if err != nil {
		// handle error
	}

	f, err := c.File()
	if err != nil {
		// handle error
	}

	closeClient := func() {
		c.Close()
		f.Close()
	}
	defer closeClient()

The PollAttachment consists of a file descriptor and its callback function. PollAttachment is used to register a file descriptor to Poller. The callback function is called when an event occurs on the file descriptor:

	pa := netpoll.PollAttachment{
		FD: int(f.Fd()),
		Callback: func(fd int, event netpoll.IOEvent, flags netpoll.IOFlags) error {
			if netpoll.IsErrorEvent(event, flags) {
				closeClient()
				return errors.ErrEngineShutdown
			}

			if netpoll.IsReadEvent(event) {
				buf := make([]byte, 64)
				// Read data from the connection.
				_, err := c.Read(buf)
				if err != nil {
					closeClient()
					return errors.ErrEngineShutdown
				}
				// Process the data...
			}

			if netpoll.IsWriteEvent(event) {
				// Write data to the connection.
				_, err := c.Write([]byte("hello"))
				if err != nil {
					closeClient()
					return errors.ErrEngineShutdown
				}
			}

			return nil
		}}

	if err := poller.AddReadWrite(&pa, false); err != nil {
		// handle error
	}

The Poller.Polling function starts the event loop monitoring file descriptors and waiting for I/O events to occur:

	poller.Polling(func(fd int, event netpoll.IOEvent, flags netpoll.IOFlags) error {
		return pa.Callback(fd, event, flags)
	})

	poller.Polling()

if you’ve enabled the build tag poll_opt.

Check out gnet/pkg for more details.

P.S. Follow me on Twitter @panjf2000 to get the latest updates about gnet!