ipfs-cluster/ipfscluster.go
2017-08-03 11:24:19 -06:00

161 lines
6.0 KiB
Go

// Package ipfscluster implements a wrapper for the IPFS deamon which
// allows to orchestrate pinning operations among several IPFS nodes.
//
// IPFS Cluster uses a go-libp2p-raft to keep a shared state between
// the different cluster peers. It also uses LibP2P to enable
// communication between its different components, which perform different
// tasks like managing the underlying IPFS daemons, or providing APIs for
// external control.
package ipfscluster
import (
"github.com/ipfs/ipfs-cluster/api"
"github.com/ipfs/ipfs-cluster/state"
rpc "github.com/hsanjuan/go-libp2p-gorpc"
cid "github.com/ipfs/go-cid"
peer "github.com/libp2p/go-libp2p-peer"
protocol "github.com/libp2p/go-libp2p-protocol"
ma "github.com/multiformats/go-multiaddr"
)
// RPCProtocol is used to send libp2p messages between cluster peers
var RPCProtocol = protocol.ID("/ipfscluster/" + Version + "/rpc")
// Component represents a piece of ipfscluster. Cluster components
// usually run their own goroutines (a http server for example). They
// communicate with the main Cluster component and other components
// (both local and remote), using an instance of rpc.Client.
type Component interface {
SetClient(*rpc.Client)
Shutdown() error
}
// Consensus is a component which keeps a shared state in
// IPFS Cluster and triggers actions on updates to that state.
// Currently, Consensus needs to be able to elect/provide a
// Cluster Leader and the implementation is very tight to
// the Cluster main component.
type Consensus interface {
Component
// Returns a channel to signal that the consensus
// algoritm is ready
Ready() <-chan struct{}
// Logs a pin operation
LogPin(c api.Pin) error
// Logs an unpin operation
LogUnpin(c api.Pin) error
LogAddPeer(addr ma.Multiaddr) error
LogRmPeer(p peer.ID) error
State() (state.State, error)
// Provide a node which is responsible to perform
// specific tasks which must only run in 1 cluster peer
Leader() (peer.ID, error)
// Only returns when the consensus state has all log
// updates applied to it
WaitForSync() error
}
// API is a component which offers an API for Cluster. This is
// a base component.
type API interface {
Component
}
// IPFSConnector is a component which allows cluster to interact with
// an IPFS daemon. This is a base component.
type IPFSConnector interface {
Component
ID() (api.IPFSID, error)
Pin(*cid.Cid) error
Unpin(*cid.Cid) error
PinLsCid(*cid.Cid) (api.IPFSPinStatus, error)
PinLs(typeFilter string) (map[string]api.IPFSPinStatus, error)
// ConnectSwarms make sure this peer's IPFS daemon is connected to
// other peers IPFS daemons.
ConnectSwarms() error
// ConfigKey returns the value for a configuration key.
// Subobjects are reached with keypaths as "Parent/Child/GrandChild...".
ConfigKey(keypath string) (interface{}, error)
// FreeSpace returns the amount of remaining space on the repo, calculated from
//"repo stat"
FreeSpace() (int, error)
// RepoSize returns the current repository size as expressed
// by "repo stat".
RepoSize() (int, error)
}
// Peered represents a component which needs to be aware of the peers
// in the Cluster and of any changes to the peer set.
type Peered interface {
AddPeer(p peer.ID)
RmPeer(p peer.ID)
//SetPeers(peers []peer.ID)
}
// PinTracker represents a component which tracks the status of
// the pins in this cluster and ensures they are in sync with the
// IPFS daemon. This component should be thread safe.
type PinTracker interface {
Component
// Track tells the tracker that a Cid is now under its supervision
// The tracker may decide to perform an IPFS pin.
Track(api.Pin) error
// Untrack tells the tracker that a Cid is to be forgotten. The tracker
// may perform an IPFS unpin operation.
Untrack(*cid.Cid) error
// StatusAll returns the list of pins with their local status.
StatusAll() []api.PinInfo
// Status returns the local status of a given Cid.
Status(*cid.Cid) api.PinInfo
// SyncAll makes sure that all tracked Cids reflect the real IPFS status.
// It returns the list of pins which were updated by the call.
SyncAll() ([]api.PinInfo, error)
// Sync makes sure that the Cid status reflect the real IPFS status.
// It returns the local status of the Cid.
Sync(*cid.Cid) (api.PinInfo, error)
// Recover retriggers a Pin/Unpin operation in Cids with error status.
Recover(*cid.Cid) (api.PinInfo, error)
}
// Informer provides Metric information from a peer. The metrics produced by
// informers are then passed to a PinAllocator which will use them to
// determine where to pin content. The metric is agnostic to the rest of
// Cluster.
type Informer interface {
Component
Name() string
GetMetric() api.Metric
}
// PinAllocator decides where to pin certain content. In order to make such
// decision, it receives the pin arguments, the peers which are currently
// allocated to the content and metrics available for all peers which could
// allocate the content.
type PinAllocator interface {
Component
// Allocate returns the list of peers that should be assigned to
// Pin content in oder of preference (from the most preferred to the
// least). The "current" map contains valid metrics for peers
// which are currently pinning the content. The candidates map
// contains the metrics for all peers which are eligible for pinning
// the content.
Allocate(c *cid.Cid, current, candidates map[peer.ID]api.Metric) ([]peer.ID, error)
}
// PeerMonitor is a component in charge of monitoring the peers in the cluster
// and providing candidates to the PinAllocator when a pin request arrives.
type PeerMonitor interface {
Component
// LogMetric stores a metric. Metrics are pushed reguarly from each peer
// to the active PeerMonitor.
LogMetric(api.Metric)
// LastMetrics returns a map with the latest metrics of matching name
// for the current cluster peers.
LastMetrics(name string) []api.Metric
// Alerts delivers alerts generated when this peer monitor detects
// a problem (i.e. metrics not arriving as expected). Alerts are used to
// trigger rebalancing operations.
Alerts() <-chan api.Alert
}