SetLinger Article - TCP Server with SetLinger

main-linger.go

package main

import (
        "log"
        "net"
        "time"
)

func main() {
        // Create a listener
        l, err := net.Listen("tcp", ":9000")
        if err != nil {
                log.Fatalf("Listener returned: %s", err)
        }
        defer l.Close()

        for {
                // Accept new connections
                c, err := l.Accept()
                if err != nil {
                        log.Fatalf("Unable to accept new connections: %s", err)
                }

                // Create a goroutine that reads and writes-back data
                go func() {
                        log.Printf("TCP Session Open")
                        // Clean up session when goroutine completes, it's ok to call Close more than once.
                        defer c.Close()

                        for {
                                b := make([]byte, 120)

                                // Read from TCP Buffer
                                _, err := c.Read(b)
                                if err != nil {
                                        log.Printf("Error reading TCP Session: %s", err)
                                        break
                                }

                                // Write-back data to TCP Client
                                _, err = c.Write(b)
                                if err != nil {
                                        log.Printf("Error writing TCP Session: %s", err)
                                        break
                                }
                        }
                }()

                // Create a goroutine that closes a session after 15 seconds
                go func() {
                        <-time.After(time.Duration(15) * time.Second)

                        // Use SetLinger to force close the connection
                        err := c.(*net.TCPConn).SetLinger(0)
                        if err != nil {
                                log.Printf("Error when setting linger: %s", err)
                        }

                        defer c.Close()
                }()
        }
}