tracker/storage/storage.go
2017-06-26 20:46:40 +02:00

133 lines
4.5 KiB
Go

package storage
import (
"errors"
"sync"
"github.com/chihaya/chihaya/bittorrent"
"github.com/chihaya/chihaya/pkg/log"
"github.com/chihaya/chihaya/pkg/stop"
)
var (
driversM sync.RWMutex
drivers = make(map[string]Driver)
)
// Driver is the interface used to initalize a new type of PeerStore.
type Driver interface {
NewPeerStore(cfg interface{}) (PeerStore, error)
}
// ErrResourceDoesNotExist is the error returned by all delete methods in the
// store if the requested resource does not exist.
var ErrResourceDoesNotExist = bittorrent.ClientError("resource does not exist")
// ErrDriverDoesNotExist is the error returned by NewPeerStore when a peer
// store driver with that name does not exist.
var ErrDriverDoesNotExist = errors.New("peer store driver with that name does not exist")
// PeerStore is an interface that abstracts the interactions of storing and
// manipulating Peers such that it can be implemented for various data stores.
type PeerStore interface {
// PutSeeder adds a Seeder to the Swarm identified by the provided
// infoHash.
PutSeeder(infoHash bittorrent.InfoHash, p bittorrent.Peer) error
// DeleteSeeder removes a Seeder from the Swarm identified by the
// provided infoHash.
//
// If the Swarm or Peer does not exist, this function should return
// ErrResourceDoesNotExist.
DeleteSeeder(infoHash bittorrent.InfoHash, p bittorrent.Peer) error
// PutLeecher adds a Leecher to the Swarm identified by the provided
// infoHash.
PutLeecher(infoHash bittorrent.InfoHash, p bittorrent.Peer) error
// DeleteLeecher removes a Leecher from the Swarm identified by the
// provided infoHash.
//
// If the Swarm or Peer does not exist, this function should return
// ErrResourceDoesNotExist.
DeleteLeecher(infoHash bittorrent.InfoHash, p bittorrent.Peer) error
// GraduateLeecher promotes a Leecher to a Seeder in the Swarm
// identified by the provided infoHash.
//
// If the given Peer is not present as a Leecher, add the Peer as a
// Seeder and return no error.
GraduateLeecher(infoHash bittorrent.InfoHash, p bittorrent.Peer) error
// AnnouncePeers is a best effort attempt to return Peers from the Swarm
// identified by the provided infoHash. The returned Peers are required
// to be either all IPv4 or all IPv6.
//
// The returned Peers should strive be:
// - as close to length equal to numWant as possible without going over
// - all IPv4 or all IPv6 depending on the provided peer
// - if seeder is true, should ideally return more leechers than seeders
// - if seeder is false, should ideally return more seeders than
// leechers
//
// Returns ErrResourceDoesNotExist if the provided infoHash is not tracked.
AnnouncePeers(infoHash bittorrent.InfoHash, seeder bool, numWant int, p bittorrent.Peer) (peers []bittorrent.Peer, err error)
// ScrapeSwarm returns information required to answer a scrape request
// about a swarm identified by the given infohash.
// The AddressFamily indicates whether or not the IPv6 swarm should be
// scraped.
// The Complete and Incomplete fields of the Scrape must be filled,
// filling the Snatches field is optional.
// If the infohash is unknown to the PeerStore, an empty Scrape is
// returned.
ScrapeSwarm(infoHash bittorrent.InfoHash, addressFamily bittorrent.AddressFamily) bittorrent.Scrape
// stop.Stopper is an interface that expects a Stop method to stop the
// PeerStore.
// For more details see the documentation in the stop package.
stop.Stopper
// log.Fielder returns a loggable version of the data used to configure and
// operate a particular peer store.
log.Fielder
}
// RegisterDriver makes a Driver available by the provided name.
//
// If called twice with the same name, the name is blank, or if the provided
// Driver is nil, this function panics.
func RegisterDriver(name string, d Driver) {
if name == "" {
panic("storage: could not register a Driver with an empty name")
}
if d == nil {
panic("storage: could not register a nil Driver")
}
driversM.Lock()
defer driversM.Unlock()
if _, dup := drivers[name]; dup {
panic("storage: RegisterDriver called twice for " + name)
}
drivers[name] = d
}
// NewPeerStore attempts to initialize a new PeerStore with given a name from
// the list of registered Drivers.
//
// If a driver does not exist, returns ErrDriverDoesNotExist.
func NewPeerStore(name string, cfg interface{}) (ps PeerStore, err error) {
driversM.RLock()
defer driversM.RUnlock()
var d Driver
d, ok := drivers[name]
if !ok {
return nil, ErrDriverDoesNotExist
}
return d.NewPeerStore(cfg)
}