raft

Documentation

Overview

Package raft implements a Consensus component for IPFS Cluster which uses Raft (go-libp2p-raft).

Index

• Constants
• Variables
• func LastStateRaw(cfg *Config) (io.Reader, bool, error)
• func SnapshotSave(cfg *Config, newState state.State, pid peer.ID) error
• type Config
  • func (cfg *Config) ConfigKey() string
  • func (cfg *Config) Default() error
  • func (cfg *Config) LoadJSON(raw []byte) error
  • func (cfg *Config) ToJSON() ([]byte, error)
  • func (cfg *Config) Validate() error
• type Consensus
  • func NewConsensus(clusterPeers []peer.ID, host host.Host, cfg *Config, state state.State) (*Consensus, error)
  • func (cc *Consensus) AddPeer(pid peer.ID) error
  • func (cc *Consensus) Clean() error
  • func (cc *Consensus) Leader() (peer.ID, error)
  • func (cc *Consensus) LogPin(pin api.Pin) error
  • func (cc *Consensus) LogUnpin(pin api.Pin) error
  • func (cc *Consensus) Peers() ([]peer.ID, error)
  • func (cc *Consensus) Ready() <-chan struct{}
  • func (cc *Consensus) RmPeer(pid peer.ID) error
  • func (cc *Consensus) Rollback(state state.State) error
  • func (cc *Consensus) SetClient(c *rpc.Client)
  • func (cc *Consensus) Shutdown() error
  • func (cc *Consensus) State() (state.State, error)
  • func (cc *Consensus) WaitForSync() error
• type LogOp
  • func (op *LogOp) ApplyTo(cstate consensus.State) (consensus.State, error)
• type LogOpType

Constants

const (
	LogOpPin = iota + 1
	LogOpUnpin
)

Type of consensus operation

Variables

var (
	DefaultDataSubFolder        = "ipfs-cluster-data"
	DefaultWaitForLeaderTimeout = 15 * time.Second
	DefaultCommitRetries        = 1
	DefaultNetworkTimeout       = 10 * time.Second
	DefaultCommitRetryDelay     = 200 * time.Millisecond
)

Configuration defaults

var RaftDataBackupKeep = 5

RaftDataBackupKeep indicates the number of data folders we keep around after consensus.Clean() has been called.

var RaftLogCacheSize = 512

RaftLogCacheSize is the maximum number of logs to cache in-memory. This is used to reduce disk I/O for the recently committed entries.

var RaftMaxSnapshots = 5

RaftMaxSnapshots indicates how many snapshots to keep in the consensus data folder. TODO: Maybe include this in Config. Not sure how useful it is to touch this anyways.

Functions

func LastStateRaw

func LastStateRaw(cfg *Config) (io.Reader, bool, error)

LastStateRaw returns the bytes of the last snapshot stored, its metadata, and a flag indicating whether any snapshot was found.

func SnapshotSave

func SnapshotSave(cfg *Config, newState state.State, pid peer.ID) error

SnapshotSave saves the provided state to a snapshot in the raft data path. Old raft data is backed up and replaced by the new snapshot

Types

type Config

type Config struct {
	config.Saver

	// A Hashicorp Raft's configuration object.
	RaftConfig *hraft.Config
	// A folder to store Raft's data.
	DataFolder string
	// LeaderTimeout specifies how long to wait for a leader before
	// failing an operation.
	WaitForLeaderTimeout time.Duration
	// NetworkTimeout specifies how long before a Raft network
	// operation is timed out
	NetworkTimeout time.Duration
	// CommitRetries specifies how many times we retry a failed commit until
	// we give up.
	CommitRetries int
	// How long to wait between retries
	CommitRetryDelay time.Duration
	// contains filtered or unexported fields
}

Config allows to configure the Raft Consensus component for ipfs-cluster. The component's configuration section is represented by ConfigJSON. Config implements the ComponentConfig interface.

func (*Config) ConfigKey

func (cfg *Config) ConfigKey() string

ConfigKey returns a human-friendly indentifier for this Config.

func (*Config) Default

func (cfg *Config) Default() error

Default initializes this configuration with working defaults.

func (*Config) LoadJSON

func (cfg *Config) LoadJSON(raw []byte) error

LoadJSON parses a json-encoded configuration (see jsonConfig). The Config will have default values for all fields not explicited in the given json object.

func (*Config) ToJSON

func (cfg *Config) ToJSON() ([]byte, error)

ToJSON returns the pretty JSON representation of a Config.

func (*Config) Validate

func (cfg *Config) Validate() error

Validate checks that this configuration has working values, at least in appearance.

type Consensus

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

Consensus handles the work of keeping a shared-state between the peers of an IPFS Cluster, as well as modifying that state and applying any updates in a thread-safe manner.

func NewConsensus

func NewConsensus(clusterPeers []peer.ID, host host.Host, cfg *Config, state state.State) (*Consensus, error)

NewConsensus builds a new ClusterConsensus component. The state is used to initialize the Consensus system, so any information in it is discarded.

func (*Consensus) AddPeer

func (cc *Consensus) AddPeer(pid peer.ID) error

AddPeer adds a new peer to participate in this consensus. It will forward the operation to the leader if this is not it.

func (*Consensus) Clean

func (cc *Consensus) Clean() error

Clean removes all raft data from disk. Next time a full new peer will be bootstrapped.

func (*Consensus) Leader

func (cc *Consensus) Leader() (peer.ID, error)

Leader returns the peerID of the Leader of the cluster. It returns an error when there is no leader.

func (*Consensus) LogPin

func (cc *Consensus) LogPin(pin api.Pin) error

LogPin submits a Cid to the shared state of the cluster. It will forward the operation to the leader if this is not it.

func (*Consensus) LogUnpin

func (cc *Consensus) LogUnpin(pin api.Pin) error

LogUnpin removes a Cid from the shared state of the cluster.

func (*Consensus) Peers

func (cc *Consensus) Peers() ([]peer.ID, error)

Peers return the current list of peers in the consensus. The list will be sorted alphabetically.

func (*Consensus) Ready

func (cc *Consensus) Ready() <-chan struct{}

Ready returns a channel which is signaled when the Consensus algorithm has finished bootstrapping and is ready to use

func (*Consensus) RmPeer

func (cc *Consensus) RmPeer(pid peer.ID) error

RmPeer removes a peer from this consensus. It will forward the operation to the leader if this is not it.

func (*Consensus) Rollback

func (cc *Consensus) Rollback(state state.State) error

Rollback replaces the current agreed-upon state with the state provided. Only the consensus leader can perform this operation.

func (*Consensus) SetClient

func (cc *Consensus) SetClient(c *rpc.Client)

SetClient makes the component ready to perform RPC requets

func (*Consensus) Shutdown

func (cc *Consensus) Shutdown() error

Shutdown stops the component so it will not process any more updates. The underlying consensus is permanently shutdown, along with the libp2p transport.

func (*Consensus) State

func (cc *Consensus) State() (state.State, error)

State retrieves the current consensus State. It may error if no State has been agreed upon or the state is not consistent. The returned State is the last agreed-upon State known by this node.

func (*Consensus) WaitForSync

func (cc *Consensus) WaitForSync() error

WaitForSync waits for a leader and for the state to be up to date, then returns.

type LogOp

type LogOp struct {
	Cid  api.PinSerial
	Type LogOpType
	// contains filtered or unexported fields
}

LogOp represents an operation for the OpLogConsensus system. It implements the consensus.Op interface and it is used by the Consensus component.

func (*LogOp) ApplyTo

func (op *LogOp) ApplyTo(cstate consensus.State) (consensus.State, error)

ApplyTo applies the operation to the State

type LogOpType

type LogOpType int

LogOpType expresses the type of a consensus Operation