import "github.com/mailru/easygo/netpoll"
Package netpoll provides a portable interface for network I/O event notification facility.
Its API is intended for monitoring multiple file descriptors to see if I/O is possible on any of them. It supports edge-triggered and level-triggered interfaces.
To get more info you could look at operating system API documentation of particular netpoll implementations:
- epoll on linux; - kqueue on bsd;
The Handle function creates netpoll.Desc for further use in Poller's methods:
desc, err := netpoll.Handle(conn, netpoll.EventRead | netpoll.EventEdgeTriggered) if err != nil { // handle error }
The Poller describes os-dependent network poller:
poller, err := netpoll.New(nil) if err != nil { // handle error } // Get netpoll descriptor with EventRead|EventEdgeTriggered. desc := netpoll.Must(netpoll.HandleRead(conn)) poller.Start(desc, func(ev netpoll.Event) { if ev&netpoll.EventReadHup != 0 { poller.Stop(desc) conn.Close() return } _, err := ioutil.ReadAll(conn) if err != nil { // handle error } })
Currently, Poller is implemented only for Linux.
epoll.go handle.go handle_unix.go netpoll.go netpoll_epoll.go util.go
const ( EPOLLIN = unix.EPOLLIN EPOLLOUT = unix.EPOLLOUT EPOLLRDHUP = unix.EPOLLRDHUP EPOLLPRI = unix.EPOLLPRI EPOLLERR = unix.EPOLLERR EPOLLHUP = unix.EPOLLHUP EPOLLET = unix.EPOLLET EPOLLONESHOT = unix.EPOLLONESHOT )
EpollEvents that are mapped to epoll_event.events possible values.
const ( // EventHup is indicates that some side of i/o operations (receive, send or // both) is closed. // Usually (depending on operating system and its version) the EventReadHup // or EventWriteHup are also set int Event value. EventHup Event = 0x10 EventReadHup = 0x20 EventWriteHup = 0x40 EventErr = 0x80 // EventPollerClosed is a special Event value the receipt of which means that the // Poller instance is closed. EventPollerClosed = 0x8000 )
Event values that could be passed to CallbackFn as additional information event.
var ( // ErrNotFiler is returned by Handle* functions to indicate that given // net.Conn does not provide access to its file descriptor. ErrNotFiler = fmt.Errorf("could not get file descriptor") // ErrClosed is returned by Poller methods to indicate that instance is // closed and operation could not be processed. ErrClosed = fmt.Errorf("poller instance is closed") // ErrRegistered is returned by Poller Start() method to indicate that // connection with the same underlying file descriptor was already // registered within the poller instance. ErrRegistered = fmt.Errorf("file descriptor is already registered in poller instance") // ErrNotRegistered is returned by Poller Stop() and Resume() methods to // indicate that connection with the same underlying file descriptor was // not registered before within the poller instance. ErrNotRegistered = fmt.Errorf("file descriptor was not registered before in poller instance") )
CallbackFn is a function that will be called on kernel i/o event notification.
type Config struct { // OnWaitError will be called from goroutine, waiting for events. OnWaitError func(error) }
Config contains options for Poller configuration.
type Desc struct {
// contains filtered or unexported fields
}
Desc is a network connection within netpoll descriptor. It's methods are not goroutine safe.
Handle creates new Desc with given conn and event. Returned descriptor could be used as argument to Start(), Resume() and Stop() methods of some Poller implementation.
HandleListener returns descriptor for a net.Listener.
HandleRead creates read descriptor for further use in Poller methods. It is the same as Handle(conn, EventRead|EventEdgeTriggered).
HandleReadOnce creates read descriptor for further use in Poller methods. It is the same as Handle(conn, EventRead|EventOneShot).
HandleReadWrite creates read and write descriptor for further use in Poller methods. It is the same as Handle(conn, EventRead|EventWrite|EventEdgeTriggered).
HandleWrite creates write descriptor for further use in Poller methods. It is the same as Handle(conn, EventWrite|EventEdgeTriggered).
HandleWriteOnce creates write descriptor for further use in Poller methods. It is the same as Handle(conn, EventWrite|EventOneShot).
Must is a helper that wraps a call to a function returning (*Desc, error). It panics if the error is non-nil and returns desc if not. It is intended for use in short Desc initializations.
NewDesc creates descriptor from custom fd.
Close closes underlying file.
type Epoll struct {
// contains filtered or unexported fields
}
Epoll represents single epoll instance.
func EpollCreate(c *EpollConfig) (*Epoll, error)
EpollCreate creates new epoll instance. It starts the wait loop in separate goroutine.
func (ep *Epoll) Add(fd int, events EpollEvent, cb func(EpollEvent)) (err error)
Add adds fd to epoll set with given events. Callback will be called on each received event from epoll. Note that _EPOLLCLOSED is triggered for every cb when epoll closed.
Close stops wait loop and closes all underlying resources.
Del removes fd from epoll set.
func (ep *Epoll) Mod(fd int, events EpollEvent) (err error)
Mod sets to listen events on fd.
type EpollConfig struct { // OnWaitError will be called from goroutine, waiting for events. OnWaitError func(error) }
EpollConfig contains options for Epoll instance configuration.
EpollEvent represents epoll events configuration bit mask.
func (evt EpollEvent) String() (str string)
String returns a string representation of EpollEvent.
Event represents netpoll configuration bit mask.
Event values that denote the type of events that caller want to receive.
Event values that configure the Poller's behavior.
String returns a string representation of Event.
type Poller interface { // Start adds desc to the observation list. // // Note that if desc was configured with OneShot event, then poller will // remove it from its observation list. If you will be interested in // receiving events after the callback, call Resume(desc). // // Note that Resume() call directly inside desc's callback could cause // deadlock. // // Note that multiple calls with same desc will produce unexpected // behavior. Start(*Desc, CallbackFn) error // Stop removes desc from the observation list. // // Note that it does not call desc.Close(). Stop(*Desc) error // Resume enables observation of desc. // // It is useful when desc was configured with EventOneShot. // It should be called only after Start(). // // Note that if there no need to observe desc anymore, you should call // Stop() to prevent memory leaks. Resume(*Desc) error }
Poller describes an object that implements logic of polling connections for i/o events such as availability of read() or write() operations.
New creates new epoll-based Poller instance with given config.
Package netpoll imports 7 packages (graph) and is imported by 2 packages. Updated 2019-09-14. Refresh now. Tools for package owners.