source: code/trunk/server.go@ 80

package jounce

import (
        "fmt"
        "log"
        "net"
        "sync"
        "time"

        "gopkg.in/irc.v3"
)

// TODO: make configurable
var keepAlivePeriod = time.Minute
var retryConnectMinDelay = time.Minute

func setKeepAlive(c net.Conn) error {
        tcpConn, ok := c.(*net.TCPConn)
        if !ok {
                return fmt.Errorf("cannot enable keep-alive on a non-TCP connection")
        }
        if err := tcpConn.SetKeepAlive(true); err != nil {
                return err
        }
        return tcpConn.SetKeepAlivePeriod(keepAlivePeriod)
}

type Logger interface {
        Print(v ...interface{})
        Printf(format string, v ...interface{})
}

type prefixLogger struct {
        logger Logger
        prefix string
}

var _ Logger = (*prefixLogger)(nil)

func (l *prefixLogger) Print(v ...interface{}) {
        v = append([]interface{}{l.prefix}, v...)
        l.logger.Print(v...)
}

func (l *prefixLogger) Printf(format string, v ...interface{}) {
        v = append([]interface{}{l.prefix}, v...)
        l.logger.Printf("%v"+format, v...)
}

type network struct {
        Network
        user *user
        conn *upstreamConn
}

func newNetwork(user *user, record *Network) *network {
        return &network{
                Network: *record,
                user:    user,
        }
}

func (net *network) run() {
        var lastTry time.Time
        for {
                if dur := time.Now().Sub(lastTry); dur < retryConnectMinDelay {
                        delay := retryConnectMinDelay - dur
                        net.user.srv.Logger.Printf("waiting %v before trying to reconnect to %q", delay.Truncate(time.Second), net.Addr)
                        time.Sleep(delay)
                }
                lastTry = time.Now()

                uc, err := connectToUpstream(net)
                if err != nil {
                        net.user.srv.Logger.Printf("failed to connect to upstream server %q: %v", net.Addr, err)
                        continue
                }

                uc.register()

                net.user.lock.Lock()
                net.conn = uc
                net.user.lock.Unlock()

                if err := uc.readMessages(); err != nil {
                        uc.logger.Printf("failed to handle messages: %v", err)
                }
                uc.Close()

                net.user.lock.Lock()
                net.conn = nil
                net.user.lock.Unlock()
        }
}

type user struct {
        User
        srv *Server

        lock            sync.Mutex
        networks        []*network
        downstreamConns []*downstreamConn
}

func newUser(srv *Server, record *User) *user {
        return &user{
                User: *record,
                srv:  srv,
        }
}

func (u *user) forEachUpstream(f func(uc *upstreamConn)) {
        u.lock.Lock()
        for _, network := range u.networks {
                uc := network.conn
                if uc == nil || !uc.registered || uc.closed {
                        continue
                }
                f(uc)
        }
        u.lock.Unlock()
}

func (u *user) forEachDownstream(f func(dc *downstreamConn)) {
        u.lock.Lock()
        for _, dc := range u.downstreamConns {
                f(dc)
        }
        u.lock.Unlock()
}

func (u *user) getNetwork(name string) *network {
        for _, network := range u.networks {
                if network.Addr == name {
                        return network
                }
        }
        return nil
}

func (u *user) run() {
        networks, err := u.srv.db.ListNetworks(u.Username)
        if err != nil {
                u.srv.Logger.Printf("failed to list networks for user %q: %v", u.Username, err)
                return
        }

        u.lock.Lock()
        for _, record := range networks {
                network := newNetwork(u, &record)
                u.networks = append(u.networks, network)

                go network.run()
        }
        u.lock.Unlock()
}

type Server struct {
        Hostname string
        Logger   Logger
        RingCap  int
        Debug    bool

        db *DB

        lock            sync.Mutex
        users           map[string]*user
        downstreamConns []*downstreamConn
}

func NewServer(db *DB) *Server {
        return &Server{
                Logger:  log.New(log.Writer(), "", log.LstdFlags),
                RingCap: 4096,
                users:   make(map[string]*user),
                db:      db,
        }
}

func (s *Server) prefix() *irc.Prefix {
        return &irc.Prefix{Name: s.Hostname}
}

func (s *Server) Run() error {
        users, err := s.db.ListUsers()
        if err != nil {
                return err
        }

        s.lock.Lock()
        for _, record := range users {
                s.Logger.Printf("starting bouncer for user %q", record.Username)
                u := newUser(s, &record)
                s.users[u.Username] = u

                go u.run()
        }
        s.lock.Unlock()

        select {}
}

func (s *Server) getUser(name string) *user {
        s.lock.Lock()
        u := s.users[name]
        s.lock.Unlock()
        return u
}

func (s *Server) Serve(ln net.Listener) error {
        for {
                netConn, err := ln.Accept()
                if err != nil {
                        return fmt.Errorf("failed to accept connection: %v", err)
                }

                setKeepAlive(netConn)

                dc := newDownstreamConn(s, netConn)
                go func() {
                        s.lock.Lock()
                        s.downstreamConns = append(s.downstreamConns, dc)
                        s.lock.Unlock()

                        if err := dc.readMessages(); err != nil {
                                dc.logger.Printf("failed to handle messages: %v", err)
                        }
                        dc.Close()

                        s.lock.Lock()
                        for i := range s.downstreamConns {
                                if s.downstreamConns[i] == dc {
                                        s.downstreamConns = append(s.downstreamConns[:i], s.downstreamConns[i+1:]...)
                                        break
                                }
                        }
                        s.lock.Unlock()
                }()
        }
}