gnet

README

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🎉🎉🎉 Feel free to join the channels about gnet on the Discord Server.

📖 Introduction

gnet is an event-driven networking framework that is ultra-fast and lightweight. It is built from scratch by exploiting epoll and kqueue and it can achieve much higher performance with lower memory consumption than Go net in many specific scenarios.

gnet and net don't share the same philosophy about network programming. Thus, building network applications with gnet can be significantly different from building them with net, and the philosophies can't be reconciled. There are other similar products written in other programming languages in the community, such as libevent, libuv, netty, twisted, tornado, etc. which work in a similar pattern as gnet under the hood.

gnet is not designed to displace the Go net, but to create an alternative in the Go ecosystem for building performance-critical network services. As a result of which, gnet is not as comprehensive as Go net, it provides only the core functionalities (in a concise API set) required by a network application and it doesn't plan on being a coverall networking framework, as I think Go net has done a good enough job in that area.

gnet sells itself as a high-performance, lightweight, non-blocking, event-driven networking framework written in pure Go which works on the transport layer with TCP/UDP protocols and Unix Domain Socket. It enables developers to implement their own protocols(HTTP, RPC, WebSocket, Redis, etc.) of application layer upon gnet for building diversified network services. For instance, you get an HTTP Server if you implement HTTP protocol upon gnet while you have a Redis Server done with the implementation of Redis protocol upon gnet and so on.

gnet derives from the project: evio with much higher performance and more features.

🚀 Features

🦖 Milestone

• High-performance event-driven looping based on a networking model of multiple threads/goroutines
• Built-in goroutine pool powered by the library ants
• Lock-free during the entire runtime
• Concise and easy-to-use APIs
• Efficient, reusable, and elastic memory buffer: (Elastic-)Ring-Buffer, Linked-List-Buffer and Elastic-Mixed-Buffer
• Multiple protocols/IPC mechanisms: TCP, UDP, and Unix Domain Socket
• Multiple load-balancing algorithms: Round-Robin, Source-Addr-Hash, and Least-Connections
• Flexible ticker event
• gnet client
• Running on Linux, macOS, Windows, and *BSD: Darwin/DragonFlyBSD/FreeBSD/NetBSD/OpenBSD
• Edge-triggered I/O support
• Multiple network addresses binding

🕊 Roadmap

• TLS support
• io_uring support
• KCP support

Windows version of gnet should only be used in development for developing and testing, it shouldn't be used in production.

🎬 Getting started

gnet is available as a Go module and we highly recommend that you use gnet via Go Modules, with Go 1.11 Modules enabled (Go 1.11+), you can just simply add import "github.com/panjf2000/gnet/v2" to the codebase and run go mod download/go mod tidy or go [build|run|test] to download the necessary dependencies automatically.

With v2

go get -u github.com/panjf2000/gnet/v2

With v1

go get -u github.com/panjf2000/gnet

🎡 Use cases

The following corporations/organizations use gnet as the underlying network service in production.

If you're also using gnet in production, please help us enrich this list by opening a pull request.

📊 Performance

Benchmarks on TechEmpower

# Hardware Environment
* 28 HT Cores Intel(R) Xeon(R) Gold 5120 CPU @ 3.20GHz
* 32GB RAM
* Dedicated Cisco 10-gigabit Ethernet switch
* Debian 12 "bookworm"
* Go1.19.x linux/amd64

This is a leaderboard of the top 50 out of 486 frameworks that encompass various programming languages worldwide, in which gnet is ranked first.

This is the full framework ranking of Go and gnet tops all the other frameworks, which makes gnet the fastest networking framework in Go.

To see the full ranking list, visit TechEmpower Benchmark Round 22.

Note that the HTTP implementation of gnet on TechEmpower is half-baked and fine-tuned for benchmark purposes only and far from production-ready.

Contrasts to the similar networking libraries

On Linux (epoll)

Test Environment

# Machine information
        OS : Ubuntu 20.04/x86_64
       CPU : 8 CPU cores, AMD EPYC 7K62 48-Core Processor
    Memory : 16.0 GiB

# Go version and settings
Go Version : go1.17.2 linux/amd64
GOMAXPROCS : 8

# Benchmark parameters
TCP connections : 1000/2000/5000/10000
Packet size     : 512/1024/2048/4096/8192/16384/32768/65536 bytes
Test duration   : 15s

Echo benchmark

On MacOS (kqueue)

Test Environment

# Machine information
        OS : MacOS Big Sur/x86_64
       CPU : 6 CPU cores, Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    Memory : 16.0 GiB

# Go version and settings
Go Version : go1.16.5 darwin/amd64
GOMAXPROCS : 12

# Benchmark parameters
TCP connections : 300/400/500/600/700
Packet size     : 512/1024/2048/4096/8192 bytes
Test duration   : 15s

Echo benchmark

⚠️ License

The source code of gnet should be distributed under the Apache-2.0 license.

👏 Contributors

Please read the Contributing Guidelines before opening a PR and thank you to all the developers who already made contributions to gnet!

⚓ Relevant Articles

• A Million WebSockets and Go
• Going Infinite, handling 1M websockets connections in Go
• Go netpoller 原生网络模型之源码全面揭秘
• gnet: 一个轻量级且高性能的 Golang 网络库
• 最快的 Go 网络框架 gnet 来啦！

💰 Backers

Support us with a monthly donation and help us continue our activities.

💎 Sponsors

Become a bronze sponsor with a monthly donation of $10 and get your logo on our README on GitHub.

☕️ Buy me a coffee

Please be sure to leave your name, GitHub account, or other social media accounts when you donate by the following means so that I can add it to the list of donors as a token of my appreciation.

        

🔑 JetBrains OS licenses

gnet has been being developed with GoLand IDE under the free JetBrains Open Source license(s) granted by JetBrains s.r.o., hence I would like to express my thanks here.

🔋 Sponsorship

This project is supported by:

Documentation

Index

• Variables
• func Rotate(eventHandler EventHandler, addrs []string, opts ...Option) error
• func Run(eventHandler EventHandler, protoAddr string, opts ...Option) error
• func Stop(ctx context.Context, protoAddr string) error
• type Action
• type AsyncCallback
• type BuiltinEventEngine
  • func (*BuiltinEventEngine) OnBoot(_ Engine) (action Action)
  • func (*BuiltinEventEngine) OnClose(_ Conn, _ error) (action Action)
  • func (*BuiltinEventEngine) OnOpen(_ Conn) (out []byte, action Action)
  • func (*BuiltinEventEngine) OnShutdown(_ Engine)
  • func (*BuiltinEventEngine) OnTick() (delay time.Duration, action Action)
  • func (*BuiltinEventEngine) OnTraffic(_ Conn) (action Action)
• type Client
  • func NewClient(eh EventHandler, opts ...Option) (cli *Client, err error)
  • func (cli *Client) Dial(network, address string) (Conn, error)
  • func (cli *Client) DialContext(network, address string, ctx interface{}) (Conn, error)
  • func (cli *Client) Enroll(c net.Conn) (Conn, error)
  • func (cli *Client) EnrollContext(c net.Conn, ctx interface{}) (Conn, error)
  • func (cli *Client) Start() error
  • func (cli *Client) Stop() (err error)
• type Conn
• type Engine
  • func (e Engine) CountConnections() (count int)
  • func (e Engine) Dup() (fd int, err error)
  • func (e Engine) Stop(ctx context.Context) error
  • func (e Engine) Validate() error
• type EventHandler
• type LoadBalancing
• type Option
  • func WithEdgeTriggeredIO(et bool) Option
  • func WithLoadBalancing(lb LoadBalancing) Option
  • func WithLockOSThread(lockOSThread bool) Option
  • func WithLogLevel(lvl logging.Level) Option
  • func WithLogPath(fileName string) Option
  • func WithLogger(logger logging.Logger) Option
  • func WithMulticastInterfaceIndex(idx int) Option
  • func WithMulticore(multicore bool) Option
  • func WithNumEventLoop(numEventLoop int) Option
  • func WithOptions(options Options) Option
  • func WithReadBufferCap(readBufferCap int) Option
  • func WithReuseAddr(reuseAddr bool) Option
  • func WithReusePort(reusePort bool) Option
  • func WithSocketRecvBuffer(recvBuf int) Option
  • func WithSocketSendBuffer(sendBuf int) Option
  • func WithTCPKeepAlive(tcpKeepAlive time.Duration) Option
  • func WithTCPNoDelay(tcpNoDelay TCPSocketOpt) Option
  • func WithTicker(ticker bool) Option
  • func WithWriteBufferCap(writeBufferCap int) Option
• type Options
• type Reader
• type Socket
• type TCPSocketOpt
• type Writer

Variables

var MaxStreamBufferCap = 64 * 1024 // 64KB

MaxStreamBufferCap is the default buffer size for each stream-oriented connection(TCP/Unix).

Functions

func Rotate

func Rotate(eventHandler EventHandler, addrs []string, opts ...Option) error

Rotate is like Run but accepts multiple network addresses.

func Run

func Run(eventHandler EventHandler, protoAddr string, opts ...Option) error

Run starts handling events on the specified address.

Address should use a scheme prefix and be formatted like `tcp://192.168.0.10:9851` or `unix://socket`. Valid network schemes:

tcp   - bind to both IPv4 and IPv6
tcp4  - IPv4
tcp6  - IPv6
udp   - bind to both IPv4 and IPv6
udp4  - IPv4
udp6  - IPv6
unix  - Unix Domain Socket

The "tcp" network scheme is assumed when one is not specified.

func Stop

func Stop(ctx context.Context, protoAddr string) error

Stop gracefully shuts down the engine without interrupting any active event-loops, it waits indefinitely for connections and event-loops to be closed and then shuts down.

Deprecated: The global Stop only shuts down the last registered Engine with the same protocol and IP:Port as the previous Engine's, which can lead to leaks of Engine if you invoke gnet.Run multiple times using the same protocol and IP:Port under the condition that WithReuseAddr(true) and WithReusePort(true) are enabled. Use Engine.Stop instead.

Types

type Action

type Action int

Action is an action that occurs after the completion of an event.

const (
	// None indicates that no action should occur following an event.
	None Action = iota

	// Close closes the connection.
	Close

	// Shutdown shutdowns the engine.
	Shutdown
)

type AsyncCallback

type AsyncCallback func(c Conn, err error) error

AsyncCallback is a callback which will be invoked after the asynchronous functions has finished executing.

Note that the parameter gnet.Conn is already released under UDP protocol, thus it's not allowed to be accessed.

type BuiltinEventEngine

type BuiltinEventEngine struct{}

BuiltinEventEngine is a built-in implementation of EventHandler which sets up each method with a default implementation, you can compose it with your own implementation of EventHandler when you don't want to implement all methods in EventHandler.

func (*BuiltinEventEngine) OnBoot

func (*BuiltinEventEngine) OnBoot(_ Engine) (action Action)

OnBoot fires when the engine is ready for accepting connections. The parameter engine has information and various utilities.

func (*BuiltinEventEngine) OnClose

func (*BuiltinEventEngine) OnClose(_ Conn, _ error) (action Action)

OnClose fires when a connection has been closed. The parameter err is the last known connection error.

func (*BuiltinEventEngine) OnOpen

func (*BuiltinEventEngine) OnOpen(_ Conn) (out []byte, action Action)

OnOpen fires when a new connection has been opened. The parameter out is the return value which is going to be sent back to the remote.

func (*BuiltinEventEngine) OnShutdown

func (*BuiltinEventEngine) OnShutdown(_ Engine)

OnShutdown fires when the engine is being shut down, it is called right after all event-loops and connections are closed.

func (*BuiltinEventEngine) OnTick

func (*BuiltinEventEngine) OnTick() (delay time.Duration, action Action)

OnTick fires immediately after the engine starts and will fire again following the duration specified by the delay return value.

func (*BuiltinEventEngine) OnTraffic

func (*BuiltinEventEngine) OnTraffic(_ Conn) (action Action)

OnTraffic fires when a local socket receives data from the remote.

type Client

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

Client of gnet.

func NewClient

func NewClient(eh EventHandler, opts ...Option) (cli *Client, err error)

NewClient creates an instance of Client.

func (*Client) Dial

func (cli *Client) Dial(network, address string) (Conn, error)

Dial is like net.Dial().

func (*Client) DialContext

func (cli *Client) DialContext(network, address string, ctx interface{}) (Conn, error)

DialContext is like Dial but also accepts an empty interface ctx that can be obtained later via Conn.Context.

func (*Client) Enroll

func (cli *Client) Enroll(c net.Conn) (Conn, error)

Enroll converts a net.Conn to gnet.Conn and then adds it into Client.

func (*Client) EnrollContext

func (cli *Client) EnrollContext(c net.Conn, ctx interface{}) (Conn, error)

EnrollContext is like Enroll but also accepts an empty interface ctx that can be obtained later via Conn.Context.

func (*Client) Start

func (cli *Client) Start() error

Start starts the client event-loop, handing IO events.

func (*Client) Stop

func (cli *Client) Stop() (err error)

Stop stops the client event-loop.

type Conn

type Conn interface {
	Reader // all methods in Reader are not concurrency-safe.
	Writer // some methods in Writer are concurrency-safe, some are not.
	Socket // all methods in Socket are concurrency-safe.

	// Context returns a user-defined context, it's not concurrency-safe,
	// you must invoke it within any method in EventHandler.
	Context() (ctx interface{})

	// SetContext sets a user-defined context, it's not concurrency-safe,
	// you must invoke it within any method in EventHandler.
	SetContext(ctx interface{})

	// LocalAddr is the connection's local socket address, it's not concurrency-safe,
	// you must invoke it within any method in EventHandler.
	LocalAddr() (addr net.Addr)

	// RemoteAddr is the connection's remote address, it's not concurrency-safe,
	// you must invoke it within any method in EventHandler.
	RemoteAddr() (addr net.Addr)

	// Wake triggers a OnTraffic event for the current connection, it's concurrency-safe.
	Wake(callback AsyncCallback) (err error)

	// CloseWithCallback closes the current connection, it's concurrency-safe.
	// Usually you should provide a non-nil callback for this method,
	// otherwise your better choice is Close().
	CloseWithCallback(callback AsyncCallback) (err error)

	// Close closes the current connection, implements net.Conn, it's concurrency-safe.
	Close() (err error)

	// SetDeadline implements net.Conn.
	SetDeadline(t time.Time) (err error)

	// SetReadDeadline implements net.Conn.
	SetReadDeadline(t time.Time) (err error)

	// SetWriteDeadline implements net.Conn.
	SetWriteDeadline(t time.Time) (err error)
}

Conn is an interface of underlying connection.

type Engine

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

Engine represents an engine context which provides some functions.

func (Engine) CountConnections

func (e Engine) CountConnections() (count int)

CountConnections counts the number of currently active connections and returns it.

func (Engine) Dup

func (e Engine) Dup() (fd int, err error)

Dup returns a copy of the underlying file descriptor of listener. It is the caller's responsibility to close dupFD when finished. Closing listener does not affect dupFD, and closing dupFD does not affect listener.

func (Engine) Stop

func (e Engine) Stop(ctx context.Context) error

Stop gracefully shuts down this Engine without interrupting any active event-loops, it waits indefinitely for connections and event-loops to be closed and then shuts down.

func (Engine) Validate

func (e Engine) Validate() error

Validate checks whether the engine is available.

type EventHandler

type EventHandler interface {
	// OnBoot fires when the engine is ready for accepting connections.
	// The parameter engine has information and various utilities.
	OnBoot(eng Engine) (action Action)

	// OnShutdown fires when the engine is being shut down, it is called right after
	// all event-loops and connections are closed.
	OnShutdown(eng Engine)

	// OnOpen fires when a new connection has been opened.
	//
	// The Conn c has information about the connection such as its local and remote addresses.
	// The parameter out is the return value which is going to be sent back to the remote.
	// Sending large amounts of data back to the remote in OnOpen is usually not recommended.
	OnOpen(c Conn) (out []byte, action Action)

	// OnClose fires when a connection has been closed.
	// The parameter err is the last known connection error.
	OnClose(c Conn, err error) (action Action)

	// OnTraffic fires when a socket receives data from the remote.
	//
	// Note that the []byte returned from Conn.Peek(int)/Conn.Next(int) is not allowed to be passed to a new goroutine,
	// as this []byte will be reused within event-loop after OnTraffic() returns.
	// If you have to use this []byte in a new goroutine, you should either make a copy of it or call Conn.Read([]byte)
	// to read data into your own []byte, then pass the new []byte to the new goroutine.
	OnTraffic(c Conn) (action Action)

	// OnTick fires immediately after the engine starts and will fire again
	// following the duration specified by the delay return value.
	OnTick() (delay time.Duration, action Action)
}

EventHandler represents the engine events' callbacks for the Run call. Each event has an Action return value that is used manage the state of the connection and engine.

type LoadBalancing

type LoadBalancing int

LoadBalancing represents the type of load-balancing algorithm.

const (
	// RoundRobin assigns the next accepted connection to the event-loop by polling event-loop list.
	RoundRobin LoadBalancing = iota

	// LeastConnections assigns the next accepted connection to the event-loop that is
	// serving the least number of active connections at the current time.
	LeastConnections

	// SourceAddrHash assigns the next accepted connection to the event-loop by hashing the remote address.
	SourceAddrHash
)

type Option

type Option func(opts *Options)

Option is a function that will set up option.

func WithEdgeTriggeredIO

func WithEdgeTriggeredIO(et bool) Option

WithEdgeTriggeredIO enables the edge-triggered I/O for the underlying epoll/kqueue event-loop.

func WithLoadBalancing

func WithLoadBalancing(lb LoadBalancing) Option

WithLoadBalancing picks the load-balancing algorithm for gnet engine.

func WithLockOSThread

func WithLockOSThread(lockOSThread bool) Option

WithLockOSThread enables LockOSThread mode for I/O event-loops.

func WithLogLevel

func WithLogLevel(lvl logging.Level) Option

WithLogLevel specifies the logging level for the local logging file.

func WithLogPath

func WithLogPath(fileName string) Option

WithLogPath specifies a local path for logging file.

func WithLogger

func WithLogger(logger logging.Logger) Option

WithLogger specifies a customized logger.

func WithMulticastInterfaceIndex

func WithMulticastInterfaceIndex(idx int) Option

WithMulticastInterfaceIndex sets the interface name where UDP multicast sockets will be bound to.

func WithMulticore

func WithMulticore(multicore bool) Option

WithMulticore enables multi-cores mode for gnet engine.

func WithNumEventLoop

func WithNumEventLoop(numEventLoop int) Option

WithNumEventLoop sets the number of event loops for gnet engine.

func WithOptions

func WithOptions(options Options) Option

WithOptions sets up all options.

func WithReadBufferCap

func WithReadBufferCap(readBufferCap int) Option

WithReadBufferCap sets ReadBufferCap for reading bytes.

func WithReuseAddr

func WithReuseAddr(reuseAddr bool) Option

WithReuseAddr sets SO_REUSEADDR socket option.

func WithReusePort

func WithReusePort(reusePort bool) Option

WithReusePort sets SO_REUSEPORT socket option.

func WithSocketRecvBuffer

func WithSocketRecvBuffer(recvBuf int) Option

WithSocketRecvBuffer sets the maximum socket receive buffer of kernel in bytes.

func WithSocketSendBuffer

func WithSocketSendBuffer(sendBuf int) Option

WithSocketSendBuffer sets the maximum socket send buffer of kernel in bytes.

func WithTCPKeepAlive

func WithTCPKeepAlive(tcpKeepAlive time.Duration) Option

WithTCPKeepAlive enables the TCP keep-alive mechanism and sets its values.

func WithTCPNoDelay

func WithTCPNoDelay(tcpNoDelay TCPSocketOpt) Option

WithTCPNoDelay enable/disable the TCP_NODELAY socket option.

func WithTicker

func WithTicker(ticker bool) Option

WithTicker indicates whether a ticker is currently set.

func WithWriteBufferCap

func WithWriteBufferCap(writeBufferCap int) Option

WithWriteBufferCap sets WriteBufferCap for pending bytes.

type Options

type Options struct {

	// Multicore indicates whether the engine will be effectively created with multi-cores, if so,
	// then you must take care with synchronizing memory between all event callbacks, otherwise,
	// it will run the engine with single thread. The number of threads in the engine will be
	// automatically assigned to the number of usable logical CPUs that can be leveraged by the
	// current process.
	Multicore bool

	// NumEventLoop is set up to start the given number of event-loop goroutines.
	// Note that a non-negative NumEventLoop will override Multicore.
	NumEventLoop int

	// LB represents the load-balancing algorithm used when assigning new connections
	// to event loops.
	LB LoadBalancing

	// ReuseAddr indicates whether to set the SO_REUSEADDR socket option.
	ReuseAddr bool

	// ReusePort indicates whether to set the SO_REUSEPORT socket option.
	ReusePort bool

	// MulticastInterfaceIndex is the index of the interface name where the multicast UDP addresses will be bound to.
	MulticastInterfaceIndex int

	// ReadBufferCap is the maximum number of bytes that can be read from the remote when the readable event comes.
	// The default value is 64KB, it can either be reduced to avoid starving the subsequent connections or increased
	// to read more data from a socket.
	//
	// Note that ReadBufferCap will always be converted to the least power of two integer value greater than
	// or equal to its real amount.
	ReadBufferCap int

	// WriteBufferCap is the maximum number of bytes that a static outbound buffer can hold,
	// if the data exceeds this value, the overflow bytes will be stored in the elastic linked list buffer.
	// The default value is 64KB.
	//
	// Note that WriteBufferCap will always be converted to the least power of two integer value greater than
	// or equal to its real amount.
	WriteBufferCap int

	// LockOSThread is used to determine whether each I/O event-loop should be associated to an OS thread,
	// it is useful when you need some kind of mechanisms like thread local storage, or invoke certain C
	// libraries (such as graphics lib: GLib) that require thread-level manipulation via cgo, or want all I/O
	// event-loops to actually run in parallel for a potential higher performance.
	LockOSThread bool

	// Ticker indicates whether the ticker has been set up.
	Ticker bool

	// TCPKeepAlive enable the TCP keep-alive mechanism (SO_KEEPALIVE) and set its value
	// on TCP_KEEPIDLE, 1/5 of its value on TCP_KEEPINTVL, and 5 on TCP_KEEPCNT.
	TCPKeepAlive time.Duration

	// TCPNoDelay controls whether the operating system should delay
	// packet transmission in hopes of sending fewer packets (Nagle's algorithm).
	// When this option is assigned to TCPNoDelay, TCP_NODELAY socket option will
	// be turned on, on the contrary, if it is assigned to TCPDelay, the socket
	// option will be turned off.
	//
	// The default is TCPNoDelay, meaning that TCP_NODELAY is turned on and data
	// will not be buffered but sent as soon as possible after a write operation.
	TCPNoDelay TCPSocketOpt

	// SocketRecvBuffer sets the maximum socket receive buffer of kernel in bytes.
	SocketRecvBuffer int

	// SocketSendBuffer sets the maximum socket send buffer of kernel in bytes.
	SocketSendBuffer int

	// LogPath specifies a local path where logs will be written, this is the easiest
	// way to set up logging, gnet instantiates a default uber-go/zap logger with this
	// given log path, you are also allowed to employ your own logger during the lifetime
	// by implementing the following logging.Logger interface.
	//
	// Note that this option can be overridden by a non-nil option Logger.
	LogPath string

	// LogLevel specifies the logging level, it should be used along with LogPath.
	LogLevel logging.Level

	// Logger is the customized logger for logging info, if it is not set,
	// then gnet will use the default logger powered by go.uber.org/zap.
	Logger logging.Logger

	// EdgeTriggeredIO enables the edge-triggered I/O for the underlying epoll/kqueue event-loop.
	// Don't enable it unless you are 100% sure what you are doing.
	// Note that this option is only available for stream-oriented protocol.
	EdgeTriggeredIO bool
}

Options are configurations for the gnet application.

type Reader

type Reader interface {
	io.Reader
	io.WriterTo

	// Next returns a slice containing the next n bytes from the buffer,
	// advancing the buffer as if the bytes had been returned by Read.
	// Calling this method has the same effect as calling Peek and Discard.
	// If the amount of the available bytes is less than requested, a pair of (0, io.ErrShortBuffer)
	// is returned.
	//
	// Note that the []byte buf returned by Next() is not allowed to be passed to a new goroutine,
	// as this []byte will be reused within event-loop.
	// If you have to use buf in a new goroutine, then you need to make a copy of buf and pass this copy
	// to that new goroutine.
	Next(n int) (buf []byte, err error)

	// Peek returns the next n bytes without advancing the inbound buffer, the returned bytes
	// remain valid until a Discard is called. If the amount of the available bytes is
	// less than requested, a pair of (0, io.ErrShortBuffer) is returned.
	//
	// Note that the []byte buf returned by Peek() is not allowed to be passed to a new goroutine,
	// as this []byte will be reused within event-loop.
	// If you have to use buf in a new goroutine, then you need to make a copy of buf and pass this copy
	// to that new goroutine.
	Peek(n int) (buf []byte, err error)

	// Discard advances the inbound buffer with next n bytes, returning the number of bytes discarded.
	Discard(n int) (discarded int, err error)

	// InboundBuffered returns the number of bytes that can be read from the current buffer.
	InboundBuffered() (n int)
}

Reader is an interface that consists of a number of methods for reading that Conn must implement.

Note that the methods in this interface are not concurrency-safe for concurrent use, you must invoke them within any method in EventHandler.

type Socket

type Socket interface {

	// Fd returns the underlying file descriptor.
	Fd() int

	// Dup returns a copy of the underlying file descriptor.
	// It is the caller's responsibility to close fd when finished.
	// Closing c does not affect fd, and closing fd does not affect c.
	//
	// The returned file descriptor is different from the
	// connection's. Attempting to change properties of the original
	// using this duplicate may or may not have the desired effect.
	Dup() (int, error)

	// SetReadBuffer sets the size of the operating system's
	// receive buffer associated with the connection.
	SetReadBuffer(bytes int) error

	// SetWriteBuffer sets the size of the operating system's
	// transmit buffer associated with the connection.
	SetWriteBuffer(bytes int) error

	// SetLinger sets the behavior of Close on a connection which still
	// has data waiting to be sent or to be acknowledged.
	//
	// If sec < 0 (the default), the operating system finishes sending the
	// data in the background.
	//
	// If sec == 0, the operating system discards any unsent or
	// unacknowledged data.
	//
	// If sec > 0, the data is sent in the background as with sec < 0. On
	// some operating systems after sec seconds have elapsed any remaining
	// unsent data may be discarded.
	SetLinger(sec int) error

	// SetKeepAlivePeriod tells operating system to send keep-alive messages on the connection
	// and sets period between TCP keep-alive probes.
	SetKeepAlivePeriod(d time.Duration) error

	// SetNoDelay controls whether the operating system should delay
	// packet transmission in hopes of sending fewer packets (Nagle's
	// algorithm).
	// The default is true (no delay), meaning that data is sent as soon as possible after a Write.
	SetNoDelay(noDelay bool) error
}

Socket is a set of functions which manipulate the underlying file descriptor of a connection.

Note that the methods in this interface are concurrency-safe for concurrent use, you don't have to invoke them within any method in EventHandler.

type TCPSocketOpt

type TCPSocketOpt int

TCPSocketOpt is the type of TCP socket options.

const (
	TCPNoDelay TCPSocketOpt = iota
	TCPDelay
)

Available TCP socket options.

type Writer

type Writer interface {
	io.Writer     // not concurrency-safe
	io.ReaderFrom // not concurrency-safe

	// Writev writes multiple byte slices to remote synchronously, it's not concurrency-safe,
	// you must invoke it within any method in EventHandler.
	Writev(bs [][]byte) (n int, err error)

	// Flush writes any buffered data to the underlying connection, it's not concurrency-safe,
	// you must invoke it within any method in EventHandler.
	Flush() (err error)

	// OutboundBuffered returns the number of bytes that can be read from the current buffer.
	// it's not concurrency-safe, you must invoke it within any method in EventHandler.
	OutboundBuffered() (n int)

	// AsyncWrite writes bytes to remote asynchronously, it's concurrency-safe,
	// you don't have to invoke it within any method in EventHandler,
	// usually you would call it in an individual goroutine.
	//
	// Note that it will go synchronously with UDP, so it is needless to call
	// this asynchronous method, we may disable this method for UDP and just
	// return ErrUnsupportedOp in the future, therefore, please don't rely on
	// this method to do something important under UDP, if you're working with UDP,
	// just call Conn.Write to send back your data.
	AsyncWrite(buf []byte, callback AsyncCallback) (err error)

	// AsyncWritev writes multiple byte slices to remote asynchronously,
	// you don't have to invoke it within any method in EventHandler,
	// usually you would call it in an individual goroutine.
	AsyncWritev(bs [][]byte, callback AsyncCallback) (err error)
}

Writer is an interface that consists of a number of methods for writing that Conn must implement.