dht

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 Go to latest Published: Sep 16, 2019 License: MIT Imports: 42 Imported by: 0

README

go-libp2p-kad-dht

standard-readme compliant GoDoc Build Status

A Kademlia DHT implementation on go-libp2p

Table of Contents

Install

go get github.com/libp2p/go-libp2p-kad-dht

Usage

Go to https://godoc.org/github.com/libp2p/go-libp2p-kad-dht.

Contribute

Contributions welcome. Please check out the issues.

Check out our contributing document for more information on how we work, and about contributing in general. Please be aware that all interactions related to libp2p are subject to the IPFS Code of Conduct.

Small note: If editing the README, please conform to the standard-readme specification.

License

MIT © Protocol Labs Inc.

Documentation

Overview

Package dht implements a distributed hash table that satisfies the ipfs routing interface. This DHT is modeled after kademlia with S/Kademlia modifications.

Package dht implements a distributed hash table that satisfies the ipfs routing interface. This DHT is modeled after Kademlia with S/Kademlia modifications.

package query implement a query manager to drive concurrent workers to query the DHT. A query is setup with a target key, a queryFunc tasked to communicate with a peer, and a set of initial peers. As the query progress, queryFunc can return closer peers that will be used to navigate closer to the target key in the DHT until an answer is reached.

Index

Constants

View Source 
const MaxRecordAge = time.Hour * 36

MaxRecordAge specifies the maximum time that any node will hold onto a record from the time its received. This does not apply to any other forms of validity that the record may contain. For example, a record may contain an ipns entry with an EOL saying its valid until the year 2020 (a great time in the future). For that record to stick around it must be rebroadcasted more frequently than once every 'MaxRecordAge'

View Source 
const NumBootstrapQueries = 5

NumBootstrapQueries defines the number of random dht queries to do to collect members of the routing table.

Variables

View Source 
var AlphaValue = 3

Alpha is the concurrency factor for asynchronous requests.

View Source 
var CloserPeerCount = KValue

The number of closer peers to send on requests.

View Source 
var DefaultBootstrapConfig = BootstrapConfig{

	Queries: 1,

	Period: time.Duration(2 * time.Minute),

	Timeout: time.Duration(10 * time.Second),
}
View Source 
var ErrReadTimeout = fmt.Errorf("timed out reading response")
View Source 
var KValue = 16

K is the maximum number of requests to perform before returning failure.

View Source 
var PoolSize = 6

Pool size is the number of nodes used for group find/set RPC calls

Functions

func Quorum 

func Quorum(n int) ropts.Option

Quorum is a DHT option that tells the DHT how many peers it needs to get values from before returning the best one.

Default: 16

Types

type BootstrapConfig 

type BootstrapConfig struct {
	Queries int           // how many queries to run per period
	Period  time.Duration // how often to run periodic bootstrap.
	Timeout time.Duration // how long to wait for a bootstrap query to run
}

BootstrapConfig specifies parameters used bootstrapping the DHT.

Note there is a tradeoff between the bootstrap period and the number of queries. We could support a higher period with less queries.

type IpfsDHT 

type IpfsDHT struct {
	Validator record.Validator
	// contains filtered or unexported fields
}

IpfsDHT is an implementation of Kademlia with S/Kademlia modifications. It is used to implement the base IpfsRouting module.

func New 

func New(ctx context.Context, h host.Host, options ...opts.Option) (*IpfsDHT, error)

New creates a new DHT with the specified host and options.

func NewDHT 

func NewDHT(ctx context.Context, h host.Host, dstore ds.Batching) *IpfsDHT

NewDHT creates a new DHT object with the given peer as the 'local' host. IpfsDHT's initialized with this function will respond to DHT requests, whereas IpfsDHT's initialized with NewDHTClient will not.

func NewDHTClient 

func NewDHTClient(ctx context.Context, h host.Host, dstore ds.Batching) *IpfsDHT

NewDHTClient creates a new DHT object with the given peer as the 'local' host. IpfsDHT clients initialized with this function will not respond to DHT requests. If you need a peer to respond to DHT requests, use NewDHT instead. NewDHTClient creates a new DHT object with the given peer as the 'local' host

func (*IpfsDHT) Bootstrap 

func (dht *IpfsDHT) Bootstrap(ctx context.Context) error

Bootstrap ensures the dht routing table remains healthy as peers come and go. it builds up a list of peers by requesting random peer IDs. The Bootstrap process will run a number of queries each time, and run every time signal fires. These parameters are configurable.

As opposed to BootstrapWithConfig, Bootstrap satisfies the routing interface

func (*IpfsDHT) BootstrapOnSignal 

func (dht *IpfsDHT) BootstrapOnSignal(cfg BootstrapConfig, signal <-chan time.Time) (goprocess.Process, error)

SignalBootstrap ensures the dht routing table remains healthy as peers come and go. it builds up a list of peers by requesting random peer IDs. The Bootstrap process will run a number of queries each time, and run every time signal fires. These parameters are configurable.

SignalBootstrap returns a process, so the user can stop it.

func (*IpfsDHT) BootstrapWithConfig 

func (dht *IpfsDHT) BootstrapWithConfig(cfg BootstrapConfig) (goprocess.Process, error)

BootstrapWithConfig ensures the dht routing table remains healthy as peers come and go. it builds up a list of peers by requesting random peer IDs. The Bootstrap process will run a number of queries each time, and run every time signal fires. These parameters are configurable.

BootstrapWithConfig returns a process, so the user can stop it.

func (*IpfsDHT) Close 

func (dht *IpfsDHT) Close() error

Close calls Process Close

func (*IpfsDHT) Context 

func (dht *IpfsDHT) Context() context.Context

Context return dht's context

func (*IpfsDHT) FindLocal 

func (dht *IpfsDHT) FindLocal(id peer.ID) pstore.PeerInfo

FindLocal looks for a peer with a given ID connected to this dht and returns the peer and the table it was found in.

func (*IpfsDHT) FindPeer 

func (dht *IpfsDHT) FindPeer(ctx context.Context, id peer.ID) (_ pstore.PeerInfo, err error)

FindPeer searches for a peer with given ID.

func (*IpfsDHT) FindPeersConnectedToPeer 

func (dht *IpfsDHT) FindPeersConnectedToPeer(ctx context.Context, id peer.ID) (<-chan *pstore.PeerInfo, error)

FindPeersConnectedToPeer searches for peers directly connected to a given peer.

func (*IpfsDHT) FindProviders 

func (dht *IpfsDHT) FindProviders(ctx context.Context, c cid.Cid) ([]pstore.PeerInfo, error)

FindProviders searches until the context expires.

func (*IpfsDHT) FindProvidersAsync 

func (dht *IpfsDHT) FindProvidersAsync(ctx context.Context, key cid.Cid, count int) <-chan pstore.PeerInfo

FindProvidersAsync is the same thing as FindProviders, but returns a channel. Peers will be returned on the channel as soon as they are found, even before the search query completes.

func (*IpfsDHT) GetClosestPeers 

func (dht *IpfsDHT) GetClosestPeers(ctx context.Context, key string) (<-chan peer.ID, error)

Kademlia 'node lookup' operation. Returns a channel of the K closest peers to the given key

func (*IpfsDHT) GetPublicKey 

func (dht *IpfsDHT) GetPublicKey(ctx context.Context, p peer.ID) (ci.PubKey, error)

func (*IpfsDHT) GetValue 

func (dht *IpfsDHT) GetValue(ctx context.Context, key string, opts ...ropts.Option) (_ []byte, err error)

GetValue searches for the value corresponding to given Key.

func (*IpfsDHT) GetValues 

func (dht *IpfsDHT) GetValues(ctx context.Context, key string, nvals int) (_ []RecvdVal, err error)

GetValues gets nvals values corresponding to the given key.

func (*IpfsDHT) Process 

func (dht *IpfsDHT) Process() goprocess.Process

Process return dht's process

func (*IpfsDHT) Provide 

func (dht *IpfsDHT) Provide(ctx context.Context, key cid.Cid, brdcst bool) (err error)

Provide makes this node announce that it can provide a value for the given key

func (*IpfsDHT) PutValue 

func (dht *IpfsDHT) PutValue(ctx context.Context, key string, value []byte, opts ...ropts.Option) (err error)

PutValue adds value corresponding to given Key. This is the top level "Store" operation of the DHT

func (*IpfsDHT) RoutingTable 

func (dht *IpfsDHT) RoutingTable() *kb.RoutingTable

RoutingTable return dht's routingTable

func (*IpfsDHT) SearchValue 

func (dht *IpfsDHT) SearchValue(ctx context.Context, key string, opts ...ropts.Option) (<-chan []byte, error)

func (*IpfsDHT) Update 

func (dht *IpfsDHT) Update(ctx context.Context, p peer.ID)

Update signals the routingTable to Update its last-seen status on the given peer.

type RecvdVal 

type RecvdVal struct {
	Val  []byte
	From peer.ID
}

RecvdVal stores a value and the peer from which we got the value.

Source Files

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