easygo: github.com/mailru/easygo/netpoll Index | Files

package netpoll

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.

Index

Package Files

epoll.go handle.go handle_unix.go netpoll.go netpoll_epoll.go util.go

Constants

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.

Variables

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")
)

type CallbackFn Uses

type CallbackFn func(Event)

CallbackFn is a function that will be called on kernel i/o event notification.

type Config Uses

type Config struct {
    // OnWaitError will be called from goroutine, waiting for events.
    OnWaitError func(error)
}

Config contains options for Poller configuration.

type Desc Uses

type Desc struct {
    // contains filtered or unexported fields
}

Desc is a network connection within netpoll descriptor. It's methods are not goroutine safe.

func Handle Uses

func Handle(conn net.Conn, event Event) (*Desc, error)

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.

func HandleListener Uses

func HandleListener(ln net.Listener, event Event) (*Desc, error)

HandleListener returns descriptor for a net.Listener.

func HandleRead Uses

func HandleRead(conn net.Conn) (*Desc, error)

HandleRead creates read descriptor for further use in Poller methods. It is the same as Handle(conn, EventRead|EventEdgeTriggered).

func HandleReadOnce Uses

func HandleReadOnce(conn net.Conn) (*Desc, error)

HandleReadOnce creates read descriptor for further use in Poller methods. It is the same as Handle(conn, EventRead|EventOneShot).

func HandleReadWrite Uses

func HandleReadWrite(conn net.Conn) (*Desc, error)

HandleReadWrite creates read and write descriptor for further use in Poller methods. It is the same as Handle(conn, EventRead|EventWrite|EventEdgeTriggered).

func HandleWrite Uses

func HandleWrite(conn net.Conn) (*Desc, error)

HandleWrite creates write descriptor for further use in Poller methods. It is the same as Handle(conn, EventWrite|EventEdgeTriggered).

func HandleWriteOnce Uses

func HandleWriteOnce(conn net.Conn) (*Desc, error)

HandleWriteOnce creates write descriptor for further use in Poller methods. It is the same as Handle(conn, EventWrite|EventOneShot).

func Must Uses

func Must(desc *Desc, err error) *Desc

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.

func NewDesc Uses

func NewDesc(fd uintptr, ev Event) *Desc

NewDesc creates descriptor from custom fd.

func (*Desc) Close Uses

func (h *Desc) Close() error

Close closes underlying file.

type Epoll Uses

type Epoll struct {
    // contains filtered or unexported fields
}

Epoll represents single epoll instance.

func EpollCreate Uses

func EpollCreate(c *EpollConfig) (*Epoll, error)

EpollCreate creates new epoll instance. It starts the wait loop in separate goroutine.

func (*Epoll) Add Uses

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.

func (*Epoll) Close Uses

func (ep *Epoll) Close() (err error)

Close stops wait loop and closes all underlying resources.

func (*Epoll) Del Uses

func (ep *Epoll) Del(fd int) (err error)

Del removes fd from epoll set.

func (*Epoll) Mod Uses

func (ep *Epoll) Mod(fd int, events EpollEvent) (err error)

Mod sets to listen events on fd.

type EpollConfig Uses

type EpollConfig struct {
    // OnWaitError will be called from goroutine, waiting for events.
    OnWaitError func(error)
}

EpollConfig contains options for Epoll instance configuration.

type EpollEvent Uses

type EpollEvent uint32

EpollEvent represents epoll events configuration bit mask.

func (EpollEvent) String Uses

func (evt EpollEvent) String() (str string)

String returns a string representation of EpollEvent.

type Event Uses

type Event uint16

Event represents netpoll configuration bit mask.

const (
    EventRead  Event = 0x1
    EventWrite       = 0x2
)

Event values that denote the type of events that caller want to receive.

const (
    EventOneShot       Event = 0x4
    EventEdgeTriggered       = 0x8
)

Event values that configure the Poller's behavior.

func (Event) String Uses

func (ev Event) String() (str string)

String returns a string representation of Event.

type Poller Uses

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.

func New Uses

func New(c *Config) (Poller, error)

New creates new epoll-based Poller instance with given config.

Package netpoll imports 7 packages (graph) and is imported by 2 packages. Updated 2018-10-05. Refresh now. Tools for package owners.