bitswap

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 Go to latest Published: Aug 22, 2018 License: MIT Imports: 33 Imported by: 0

README

go-bitswap

Coverage Status Travis CI

An implementation of the bitswap protocol in go!

Table of Contents

Protocol

Bitswap is the data trading module for ipfs, it manages requesting and sending blocks to and from other peers in the network. Bitswap has two main jobs, the first is to acquire blocks requested by the client from the network. The second is to judiciously send blocks in its possession to other peers who want them.

Bitswap is a message based protocol, as opposed to response-reply. All messages contain wantlists, or blocks. Upon receiving a wantlist, a node should consider sending out wanted blocks if they have them. Upon receiving blocks, the node should send out a notification called a 'Cancel' signifying that they no longer want the block. At a protocol level, bitswap is very simple.

Implementation

Internally, when a message with a wantlist is received, it is sent to the decision engine to be considered, and blocks that we have that are wanted are placed into the peer request queue. Any block we possess that is wanted by another peer has a task in the peer request queue created for it. The peer request queue is a priority queue that sorts available tasks by some metric, currently, that metric is very simple and aims to fairly address the tasks of each other peer. More advanced decision logic will be implemented in the future. Task workers pull tasks to be done off of the queue, retrieve the block to be sent, and send it off. The number of task workers is limited by a constant factor.

Client requests for new blocks are handled by the want manager, for every new block (or set of blocks) wanted, the 'WantBlocks' method is invoked. The want manager then ensures that connected peers are notified of the new block that we want by sending the new entries to a message queue for each peer. The message queue will loop while there is work available and do the following: 1) Ensure it has a connection to its peer, 2) grab the message to be sent, and 3) send it. If new messages are added while the loop is in steps 1 or 3, the messages are combined into one to avoid having to keep an actual queue and send multiple messages. The same process occurs when the client receives a block and sends a cancel message for it.

Contribute

PRs are welcome!

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

License

MIT © Juan Batiz-Benet

Documentation

Overview

package bitswap implements the IPFS exchange interface with the BitSwap bilateral exchange protocol.

Index

Constants

This section is empty.

Variables

View Source 
var ErrAlreadyHaveBlock = errors.New("already have block")
View Source 
var (
	HasBlockBufferSize = 256
)
View Source 
var TaskWorkerCount = 8

Functions

func New 

func New(parent context.Context, network bsnet.BitSwapNetwork,
	bstore blockstore.Blockstore) exchange.Interface

New initializes a BitSwap instance that communicates over the provided BitSwapNetwork. This function registers the returned instance as the network delegate. Runs until context is cancelled.

Types

type Bitswap 

type Bitswap struct {
	// contains filtered or unexported fields
}

Bitswap instances implement the bitswap protocol.

func (*Bitswap) CancelWants 

func (bs *Bitswap) CancelWants(cids []*cid.Cid, ses uint64)

CancelWant removes a given key from the wantlist

func (*Bitswap) Close 

func (bs *Bitswap) Close() error

func (*Bitswap) GetBlock 

func (bs *Bitswap) GetBlock(parent context.Context, k *cid.Cid) (blocks.Block, error)

GetBlock attempts to retrieve a particular block from peers within the deadline enforced by the context.

func (*Bitswap) GetBlocks 

func (bs *Bitswap) GetBlocks(ctx context.Context, keys []*cid.Cid) (<-chan blocks.Block, error)

GetBlocks returns a channel where the caller may receive blocks that correspond to the provided |keys|. Returns an error if BitSwap is unable to begin this request within the deadline enforced by the context.

NB: Your request remains open until the context expires. To conserve resources, provide a context with a reasonably short deadline (ie. not one that lasts throughout the lifetime of the server)

func (*Bitswap) GetWantlist 

func (bs *Bitswap) GetWantlist() []*cid.Cid

func (*Bitswap) HasBlock 

func (bs *Bitswap) HasBlock(blk blocks.Block) error

HasBlock announces the existence of a block to this bitswap service. The service will potentially notify its peers.

func (*Bitswap) IsOnline 

func (bs *Bitswap) IsOnline() bool

func (*Bitswap) LedgerForPeer 

func (bs *Bitswap) LedgerForPeer(p peer.ID) *decision.Receipt

func (*Bitswap) NewSession 

func (bs *Bitswap) NewSession(ctx context.Context) *Session

NewSession creates a new bitswap session whose lifetime is bounded by the given context

func (*Bitswap) PeerConnected 

func (bs *Bitswap) PeerConnected(p peer.ID)

Connected/Disconnected warns bitswap about peer connections

func (*Bitswap) PeerDisconnected 

func (bs *Bitswap) PeerDisconnected(p peer.ID)

Connected/Disconnected warns bitswap about peer connections

func (*Bitswap) ReceiveError 

func (bs *Bitswap) ReceiveError(err error)

func (*Bitswap) ReceiveMessage 

func (bs *Bitswap) ReceiveMessage(ctx context.Context, p peer.ID, incoming bsmsg.BitSwapMessage)

func (*Bitswap) SessionsForBlock 

func (bs *Bitswap) SessionsForBlock(c *cid.Cid) []*Session

SessionsForBlock returns a slice of all sessions that may be interested in the given cid

func (*Bitswap) Stat 

func (bs *Bitswap) Stat() (*Stat, error)

func (*Bitswap) WantlistForPeer 

func (bs *Bitswap) WantlistForPeer(p peer.ID) []*cid.Cid

type Instance 

type Instance struct {
	Peer     peer.ID
	Exchange *Bitswap
	// contains filtered or unexported fields
}

func MkSession 

func MkSession(ctx context.Context, net tn.Network, p testutil.Identity) Instance

session creates a test bitswap session.

NB: It's easy make mistakes by providing the same peer ID to two different sessions. To safeguard, use the SessionGenerator to generate sessions. It's just a much better idea.

func (*Instance) Blockstore 

func (i *Instance) Blockstore() blockstore.Blockstore

func (*Instance) SetBlockstoreLatency 

func (i *Instance) SetBlockstoreLatency(t time.Duration) time.Duration

type Session 

type Session struct {
	// contains filtered or unexported fields
}

Session holds state for an individual bitswap transfer operation. This allows bitswap to make smarter decisions about who to send wantlist info to, and who to request blocks from

func (*Session) GetBlock 

func (s *Session) GetBlock(parent context.Context, k *cid.Cid) (blocks.Block, error)

GetBlock fetches a single block

func (*Session) GetBlocks 

func (s *Session) GetBlocks(ctx context.Context, keys []*cid.Cid) (<-chan blocks.Block, error)

GetBlocks fetches a set of blocks within the context of this session and returns a channel that found blocks will be returned on. No order is guaranteed on the returned blocks.

type SessionGenerator 

type SessionGenerator struct {
	// contains filtered or unexported fields
}

TODO move this SessionGenerator to the core package and export it as the core generator

func NewTestSessionGenerator 

func NewTestSessionGenerator(
	net tn.Network) SessionGenerator

WARNING: this uses RandTestBogusIdentity DO NOT USE for NON TESTS!

func (*SessionGenerator) Close 

func (g *SessionGenerator) Close() error

func (*SessionGenerator) Instances 

func (g *SessionGenerator) Instances(n int) []Instance

func (*SessionGenerator) Next 

func (g *SessionGenerator) Next() Instance

type Stat 

type Stat struct {
	ProvideBufLen   int
	Wantlist        []*cid.Cid
	Peers           []string
	BlocksReceived  uint64
	DataReceived    uint64
	BlocksSent      uint64
	DataSent        uint64
	DupBlksReceived uint64
	DupDataReceived uint64
}

type WantManager 

type WantManager struct {
	// contains filtered or unexported fields
}

func NewWantManager 

func NewWantManager(ctx context.Context, network bsnet.BitSwapNetwork) *WantManager

func (*WantManager) CancelWants 

func (pm *WantManager) CancelWants(ctx context.Context, ks []*cid.Cid, peers []peer.ID, ses uint64)

CancelWants removes the given cids from the wantlist, tracked by the given session

func (*WantManager) Connected 

func (pm *WantManager) Connected(p peer.ID)

func (*WantManager) ConnectedPeers 

func (pm *WantManager) ConnectedPeers() []peer.ID

func (*WantManager) Disconnected 

func (pm *WantManager) Disconnected(p peer.ID)

func (*WantManager) Run 

func (pm *WantManager) Run()

TODO: use goprocess here once i trust it

func (*WantManager) SendBlock 

func (pm *WantManager) SendBlock(ctx context.Context, env *engine.Envelope)

func (*WantManager) WantBlocks 

func (pm *WantManager) WantBlocks(ctx context.Context, ks []*cid.Cid, peers []peer.ID, ses uint64)

WantBlocks adds the given cids to the wantlist, tracked by the given session

Source Files

View all Source files

Directories

Path Synopsis
package decision implements the decision engine for the bitswap service.
 package decision implements the decision engine for the bitswap service.
pb
package wantlist implements an object for bitswap that contains the keys that a given peer wants.
 package wantlist implements an object for bitswap that contains the keys that a given peer wants.

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