tracker/tracker/tracker.go
2014-07-21 03:58:07 -04:00

108 lines
2.7 KiB
Go

// Copyright 2014 The Chihaya Authors. All rights reserved.
// Use of this source code is governed by the BSD 2-Clause license,
// which can be found in the LICENSE file.
// Package tracker provides a generic interface for manipulating a
// BitTorrent tracker's fast-moving data.
package tracker
import (
"time"
"github.com/golang/glog"
"github.com/chihaya/chihaya/backend"
"github.com/chihaya/chihaya/config"
"github.com/chihaya/chihaya/tracker/models"
)
// Tracker represents the logic necessary to service BitTorrent announces,
// independently of the underlying data transports used.
type Tracker struct {
cfg *config.Config
Pool Pool
backend backend.Conn
}
// New creates a new Tracker, and opens any necessary connections.
// Maintenance routines are automatically spawned in the background.
func New(cfg *config.Config) (*Tracker, error) {
pool, err := Open(&cfg.Tracker)
if err != nil {
return nil, err
}
bc, err := backend.Open(&cfg.Backend)
if err != nil {
return nil, err
}
go purgeInactivePeers(
pool,
cfg.PurgeInactiveTorrents,
cfg.Announce.Duration*2,
cfg.Announce.Duration,
)
return &Tracker{
cfg: cfg,
Pool: pool,
backend: bc,
}, nil
}
// Close gracefully shutdowns a Tracker by closing any database connections.
func (tkr *Tracker) Close() (err error) {
err = tkr.Pool.Close()
if err != nil {
return
}
err = tkr.backend.Close()
if err != nil {
return
}
return
}
// Writer serializes a tracker's responses, and is implemented for each
// response transport used by the tracker.
//
// Note, data passed into any of these functions will not contain sensitive
// information, so it may be passed back the client freely.
type Writer interface {
WriteError(err error) error
WriteAnnounce(*models.AnnounceResponse) error
WriteScrape(*models.ScrapeResponse) error
}
// purgeInactivePeers periodically walks the torrent database and removes
// peers that haven't announced recently.
//
// The default threshold is 2x the announce interval, which gives delayed
// peers a chance to stay alive, while ensuring the majority of responses
// contain active peers.
//
// The default interval is equal to the announce interval, since this is a
// relatively expensive operation.
func purgeInactivePeers(p Pool, purgeEmptyTorrents bool, threshold, interval time.Duration) {
for _ = range time.NewTicker(interval).C {
before := time.Now().Add(-threshold)
glog.V(0).Infof("Purging peers with no announces since %s", before)
conn, err := p.Get()
if err != nil {
glog.Error("Unable to get connection for a routine")
continue
}
err = conn.PurgeInactivePeers(purgeEmptyTorrents, before)
if err != nil {
glog.Errorf("Error purging torrents: %s", err)
}
conn.Close()
}
}