waku-org/go-waku

package peer_exchange

import (
    "errors"

    "github.com/libp2p/go-libp2p/core/host"
    "github.com/libp2p/go-libp2p/core/peer"
    "github.com/multiformats/go-multiaddr"
    "github.com/waku-org/go-waku/waku/v2/peermanager"
    "go.uber.org/zap"
    "golang.org/x/time/rate"
)

type PeerExchangeParameters struct {
    limiter *rate.Limiter
}

type Option func(*PeerExchangeParameters)

// WithRateLimiter is an option used to specify a rate limiter for requests received in lightpush protocol
func WithRateLimiter(r rate.Limit, b int) Option {
    return func(params *PeerExchangeParameters) {
        params.limiter = rate.NewLimiter(r, b)
    }
}

type PeerExchangeRequestParameters struct {
    host              host.Host
    selectedPeer      peer.ID
    peerAddr          multiaddr.Multiaddr
    peerSelectionType peermanager.PeerSelection
    preferredPeers    peer.IDSlice
    pm                *peermanager.PeerManager
    log               *zap.Logger
    shard             int
    clusterID         int
}

type RequestOption func(*PeerExchangeRequestParameters) error

// WithPeer is an option used to specify the peerID to fetch peers from
func WithPeer(p peer.ID) RequestOption {
    return func(params *PeerExchangeRequestParameters) error {
        params.selectedPeer = p
        if params.peerAddr != nil {
            return errors.New("peerAddr and peerId options are mutually exclusive")
        }
        return nil
    }
}

// WithPeerAddr is an option used to specify a peerAddress to fetch peers from
// This new peer will be added to peerStore.
// Note that this option is mutually exclusive to WithPeerAddr, only one of them can be used.
func WithPeerAddr(pAddr multiaddr.Multiaddr) RequestOption {
    return func(params *PeerExchangeRequestParameters) error {
        params.peerAddr = pAddr
        if params.selectedPeer != "" {
            return errors.New("peerAddr and peerId options are mutually exclusive")
        }
        return nil
    }
}

// WithAutomaticPeerSelection is an option used to randomly select a peer from the Waku peer store
// to obtains peers from. If a list of specific peers is passed, the peer will be chosen
// from that list assuming it supports the chosen protocol, otherwise it will chose a peer
// from the node peerstore
// Note: this option can only be used if WakuNode is initialized which internally intializes the peerManager
func WithAutomaticPeerSelection(fromThesePeers ...peer.ID) RequestOption {
    return func(params *PeerExchangeRequestParameters) error {
        params.peerSelectionType = peermanager.Automatic
        params.preferredPeers = fromThesePeers
        return nil
    }
}

// WithFastestPeerSelection is an option used to select a peer from the peer store
// with the lowest ping. If a list of specific peers is passed, the peer will be chosen
// from that list assuming it supports the chosen protocol, otherwise it will chose a peer
// from the node peerstore
func WithFastestPeerSelection(fromThesePeers ...peer.ID) RequestOption {
    return func(params *PeerExchangeRequestParameters) error {
        params.peerSelectionType = peermanager.LowestRTT
        params.preferredPeers = fromThesePeers
        return nil
    }
}

// DefaultOptions are the default options to be used when using the lightpush protocol
func DefaultOptions(host host.Host) []RequestOption {
    return []RequestOption{
        WithAutomaticPeerSelection(),
    }
}

// Use this if you want to filter peers by specific shards
func FilterByShard(clusterID int, shard int) RequestOption {
    return func(params *PeerExchangeRequestParameters) error {
        params.shard = shard
        params.clusterID = clusterID
        return nil
    }
}