peerstore

Documentation

Overview

Package peerstore provides types and interfaces for local storage of address information, metadata, and public key material about libp2p peers.

Index

• Constants
• Variables
• func AddrInfos(ps Peerstore, peers []peer.ID) []peer.AddrInfo
• type AddrBook
• type CertifiedAddrBook
  • func GetCertifiedAddrBook(ab AddrBook) (cab CertifiedAddrBook, ok bool)
• type KeyBook
• type Metrics
• type PeerMetadata
• type Peerstore
• type ProtoBook

Constants

const (
	// PermanentAddrTTL is the ttl for a "permanent address" (e.g. bootstrap nodes).
	PermanentAddrTTL = math.MaxInt64 - iota

	// ConnectedAddrTTL is the ttl used for the addresses of a peer to whom
	// we're connected directly. This is basically permanent, as we will
	// clear them + re-add under a TempAddrTTL after disconnecting.
	ConnectedAddrTTL
)

Permanent TTLs (distinct so we can distinguish between them, constant as they are, in fact, permanent)

Variables

var (
	// AddressTTL is the expiration time of addresses.
	AddressTTL = time.Hour

	// TempAddrTTL is the ttl used for a short-lived address.
	TempAddrTTL = time.Minute * 2

	// RecentlyConnectedAddrTTL is used when we recently connected to a peer.
	// It means that we are reasonably certain of the peer's address.
	RecentlyConnectedAddrTTL = time.Minute * 30

	// OwnObservedAddrTTL is used for our own external addresses observed by peers.
	OwnObservedAddrTTL = time.Minute * 30
)

var ErrNotFound = errors.New("item not found")

Functions

func AddrInfos

func AddrInfos(ps Peerstore, peers []peer.ID) []peer.AddrInfo

AddrInfos returns an AddrInfo for each specified peer ID, in-order.

Types

type AddrBook

type AddrBook interface {
	// AddAddr calls AddAddrs(p, []ma.Multiaddr{addr}, ttl)
	AddAddr(p peer.ID, addr ma.Multiaddr, ttl time.Duration)

	// AddAddrs gives this AddrBook addresses to use, with a given ttl
	// (time-to-live), after which the address is no longer valid.
	// If the manager has a longer TTL, the operation is a no-op for that address
	AddAddrs(p peer.ID, addrs []ma.Multiaddr, ttl time.Duration)

	// SetAddr calls mgr.SetAddrs(p, addr, ttl)
	SetAddr(p peer.ID, addr ma.Multiaddr, ttl time.Duration)

	// SetAddrs sets the ttl on addresses. This clears any TTL there previously.
	// This is used when we receive the best estimate of the validity of an address.
	SetAddrs(p peer.ID, addrs []ma.Multiaddr, ttl time.Duration)

	// UpdateAddrs updates the addresses associated with the given peer that have
	// the given oldTTL to have the given newTTL.
	UpdateAddrs(p peer.ID, oldTTL time.Duration, newTTL time.Duration)

	// Addrs returns all known (and valid) addresses for a given peer.
	Addrs(p peer.ID) []ma.Multiaddr

	// AddrStream returns a channel that gets all addresses for a given
	// peer sent on it. If new addresses are added after the call is made
	// they will be sent along through the channel as well.
	AddrStream(context.Context, peer.ID) <-chan ma.Multiaddr

	// ClearAddresses removes all previously stored addresses.
	ClearAddrs(p peer.ID)

	// PeersWithAddrs returns all the peer IDs stored in the AddrBook.
	PeersWithAddrs() peer.IDSlice
}

AddrBook holds the multiaddrs of peers.

type CertifiedAddrBook

type CertifiedAddrBook interface {
	// ConsumePeerRecord adds addresses from a signed peer.PeerRecord (contained in
	// a record.Envelope), which will expire after the given TTL.
	//
	// The 'accepted' return value indicates that the record was successfully processed
	// and integrated into the CertifiedAddrBook state. If 'accepted' is false but no
	// error is returned, it means that the record was ignored, most likely because
	// a newer record exists for the same peer.
	//
	// Signed records added via this method will be stored without
	// alteration as long as the address TTLs remain valid. The Envelopes
	// containing the PeerRecords can be retrieved by calling GetPeerRecord(peerID).
	//
	// If the signed PeerRecord belongs to a peer that already has certified
	// addresses in the CertifiedAddrBook, the new addresses will replace the
	// older ones, if the new record has a higher sequence number than the
	// existing record. Attempting to add a peer record with a
	// sequence number that's <= an existing record for the same peer will not
	// result in an error, but the record will be ignored, and the 'accepted'
	// bool return value will be false.
	//
	// If the CertifiedAddrBook is also an AddrBook (which is most likely the case),
	// adding certified addresses for a peer will *replace* any
	// existing non-certified addresses for that peer, and only the certified
	// addresses will be returned from AddrBook.Addrs thereafter.
	//
	// Likewise, once certified addresses have been added for a given peer,
	// any non-certified addresses added via AddrBook.AddAddrs or
	// AddrBook.SetAddrs will be ignored. AddrBook.SetAddrs may still be used
	// to update the TTL of certified addresses that have previously been
	// added via ConsumePeerRecord.
	ConsumePeerRecord(s *record.Envelope, ttl time.Duration) (accepted bool, err error)

	// GetPeerRecord returns an Envelope containing a PeerRecord for the
	// given peer id, if one exists.
	// Returns nil if no signed PeerRecord exists for the peer.
	GetPeerRecord(p peer.ID) *record.Envelope
}

CertifiedAddrBook manages "self-certified" addresses for remote peers. Self-certified addresses are contained in peer.PeerRecords which are wrapped in a record.Envelope and signed by the peer to whom they belong.

Certified addresses (CA) are generally more secure than uncertified addresses (UA). Consequently, CAs beat and displace UAs. When the peerstore learns CAs for a peer, it will reject UAs for the same peer (as long as the former haven't expired). Furthermore, peer records act like sequenced snapshots of CAs. Therefore, processing a peer record that's newer than the last one seen overwrites all addresses with the incoming ones.

This interface is most useful when combined with AddrBook. To test whether a given AddrBook / Peerstore implementation supports certified addresses, callers should use the GetCertifiedAddrBook helper or type-assert on the CertifiedAddrBook interface:

if cab, ok := aPeerstore.(CertifiedAddrBook); ok {
    cab.ConsumePeerRecord(signedPeerRecord, aTTL)
}

func GetCertifiedAddrBook

func GetCertifiedAddrBook(ab AddrBook) (cab CertifiedAddrBook, ok bool)

GetCertifiedAddrBook is a helper to "upcast" an AddrBook to a CertifiedAddrBook by using type assertion. If the given AddrBook is also a CertifiedAddrBook, it will be returned, and the ok return value will be true. Returns (nil, false) if the AddrBook is not a CertifiedAddrBook.

Note that since Peerstore embeds the AddrBook interface, you can also call GetCertifiedAddrBook(myPeerstore).

type KeyBook

type KeyBook interface {
	// PubKey stores the public key of a peer.
	PubKey(peer.ID) ic.PubKey

	// AddPubKey stores the public key of a peer.
	AddPubKey(peer.ID, ic.PubKey) error

	// PrivKey returns the private key of a peer, if known. Generally this might only be our own
	// private key, see
	// https://discuss.libp2p.io/t/what-is-the-purpose-of-having-map-peer-id-privatekey-in-peerstore/74.
	PrivKey(peer.ID) ic.PrivKey

	// AddPrivKey stores the private key of a peer.
	AddPrivKey(peer.ID, ic.PrivKey) error

	// PeersWithKeys returns all the peer IDs stored in the KeyBook.
	PeersWithKeys() peer.IDSlice

	// RemovePeer removes all keys associated with a peer.
	RemovePeer(peer.ID)
}

KeyBook tracks the keys of Peers.

type Metrics

type Metrics interface {
	// RecordLatency records a new latency measurement
	RecordLatency(peer.ID, time.Duration)

	// LatencyEWMA returns an exponentially-weighted moving avg.
	// of all measurements of a peer's latency.
	LatencyEWMA(peer.ID) time.Duration

	// RemovePeer removes all metrics stored for a peer.
	RemovePeer(peer.ID)
}

Metrics tracks metrics across a set of peers.

type PeerMetadata

type PeerMetadata interface {
	// Get / Put is a simple registry for other peer-related key/value pairs.
	// If we find something we use often, it should become its own set of
	// methods. This is a last resort.
	Get(p peer.ID, key string) (interface{}, error)
	Put(p peer.ID, key string, val interface{}) error

	// RemovePeer removes all values stored for a peer.
	RemovePeer(peer.ID)
}

PeerMetadata can handle values of any type. Serializing values is up to the implementation. Dynamic type introspection may not be supported, in which case explicitly enlisting types in the serializer may be required.

Refer to the docs of the underlying implementation for more information.

type Peerstore

type Peerstore interface {
	io.Closer

	AddrBook
	KeyBook
	PeerMetadata
	Metrics
	ProtoBook

	// PeerInfo returns a peer.PeerInfo struct for given peer.ID.
	// This is a small slice of the information Peerstore has on
	// that peer, useful to other services.
	PeerInfo(peer.ID) peer.AddrInfo

	// Peers returns all the peer IDs stored across all inner stores.
	Peers() peer.IDSlice
}

Peerstore provides a thread-safe store of Peer related information.

type ProtoBook

type ProtoBook interface {
	GetProtocols(peer.ID) ([]protocol.ID, error)
	AddProtocols(peer.ID, ...protocol.ID) error
	SetProtocols(peer.ID, ...protocol.ID) error
	RemoveProtocols(peer.ID, ...protocol.ID) error

	// SupportsProtocols returns the set of protocols the peer supports from among the given protocols.
	// If the returned error is not nil, the result is indeterminate.
	SupportsProtocols(peer.ID, ...protocol.ID) ([]protocol.ID, error)

	// FirstSupportedProtocol returns the first protocol that the peer supports among the given protocols.
	// If the peer does not support any of the given protocols, this function will return an empty protocol.ID and a nil error.
	// If the returned error is not nil, the result is indeterminate.
	FirstSupportedProtocol(peer.ID, ...protocol.ID) (protocol.ID, error)

	// RemovePeer removes all protocols associated with a peer.
	RemovePeer(peer.ID)
}

ProtoBook tracks the protocols supported by peers.