raftio

type ChunkSinkFactory func() IChunkSink

type IChunkSink interface {
	// Close closes the sink instance and releases all resources held by it.
	Close()
	// AddChunk adds a new snapshot chunk to the snapshot chunk sink. All chunks
	// belong to the snapshot will be combined into the snapshot image and then
	// be passed to Dragonboat once all member chunks are received.
	AddChunk(chunk pb.SnapshotChunk)
	// Tick moves forward the internal logic clock. It is suppose to be called
	// roughly every second.
	Tick()
}

type IConnection interface {
	// Close closes the IConnection instance.
	Close()
	// SendMessageBatch sends the specified message batch to the target. It is
	// recommended to deliver the message batch to the target in order to enjoy
	// best possible performance, but out of order delivery is allowed at the
	// cost of reduced performance.
	SendMessageBatch(batch pb.MessageBatch) error
}

type IContext interface {
	// Destroy destroys the IContext instance.
	Destroy()
	// Reset resets the IContext instance, all previous returned keys and
	// buffers will be put back to the IContext instance and be ready to
	// be used for the next iteration.
	Reset()
	// GetKey returns a reusable key.
	GetKey() IReusableKey
	// GetValueBuffer returns a byte buffer with at least sz bytes in length.
	GetValueBuffer(sz uint64) []byte
	// GetUpdates return a raftpb.Update slice,
	GetUpdates() []pb.Update
	// GetWriteBatch returns a write batch or transaction instance.
	GetWriteBatch() interface{}
	// GetEntryBatch returns an entry batch instance.
	GetEntryBatch() pb.EntryBatch
	// GetLastEntryBatch returns an entry batch instance.
	GetLastEntryBatch() pb.EntryBatch
}

type ILogDB interface {
	// Name returns the type name of the ILogDB instance.
	Name() string
	// Close closes the ILogDB instance.
	Close()
	// GetLogDBThreadContext returns a new IContext instance.
	GetLogDBThreadContext() IContext
	// ListNodeInfo lists all available NodeInfo found in the log DB.
	ListNodeInfo() ([]NodeInfo, error)
	// SaveBootstrapInfo saves the specified bootstrap info to the log DB.
	SaveBootstrapInfo(clusterID uint64,
		nodeID uint64, bootstrap pb.Bootstrap) error
	// GetBootstrapInfo returns saved bootstrap info from log DB. It returns
	// ErrNoBootstrapInfo when there is no previously saved bootstrap info for
	// the specified node.
	GetBootstrapInfo(clusterID uint64, nodeID uint64) (*pb.Bootstrap, error)
	// SaveRaftState atomically saves the Raft states, log entries and snapshots
	// metadata found in the pb.Update list to the log DB.
	SaveRaftState(updates []pb.Update, ctx IContext) error
	// IterateEntries returns the continuous Raft log entries of the specified
	// Raft node between the index value range of [low, high) up to a max size
	// limit of maxSize bytes. It returns the located log entries, their total
	// size in bytes and the occurred error.
	IterateEntries(ents []pb.Entry,
		size uint64, clusterID uint64, nodeID uint64, low uint64,
		high uint64, maxSize uint64) ([]pb.Entry, uint64, error)
	// ReadRaftState returns the persistented raft state found in Log DB.
	ReadRaftState(clusterID uint64,
		nodeID uint64, lastIndex uint64) (*RaftState, error)
	// RemoveEntriesTo removes entries associated with the specified Raft node up
	// to the specified index.
	RemoveEntriesTo(clusterID uint64, nodeID uint64, index uint64) error
	// SaveSnapshots saves all snapshot metadata found in the pb.Update list.
	SaveSnapshots([]pb.Update) error
	// DeleteSnapshot removes the specified snapshot metadata from the log DB.
	DeleteSnapshot(clusterID uint64, nodeID uint64, index uint64) error
	// ListSnapshots lists all available snapshots associated with the specified
	// Raft node.
	ListSnapshots(clusterID uint64, nodeID uint64) ([]pb.Snapshot, error)
}

type IRaftRPC interface {
	// Name returns the type name of the IRaftRPC instance.
	Name() string
	// Start launches the Raft RPC module and make it ready to start sending and
	// receiving Raft messages.
	Start() error
	// Stop stops the Raft RPC instance.
	Stop()
	// GetConnection returns an IConnection instance responsible for
	// sending Raft messages to the specified target nodehost.
	GetConnection(ctx context.Context, target string) (IConnection, error)
	// GetSnapshotConnection returns an ISnapshotConnection instance used for
	// sending snapshot chunks to the specified target nodehost.
	GetSnapshotConnection(ctx context.Context,
		target string) (ISnapshotConnection, error)
}

type IReusableKey interface {
	SetEntryBatchKey(clusterID uint64, nodeID uint64, index uint64)
	// SetEntryKey sets the key to be an entry key for the specified Raft node
	// with the specified entry index.
	SetEntryKey(clusterID uint64, nodeID uint64, index uint64)
	// SetStateKey sets the key to be an persistent state key suitable
	// for the specified Raft cluster node.
	SetStateKey(clusterID uint64, nodeID uint64)
	// SetMaxIndexKey sets the key to be the max possible index key for the
	// specified Raft cluster node.
	SetMaxIndexKey(clusterID uint64, nodeID uint64)
	// Key returns the underlying byte slice of the key.
	Key() []byte
	// Release releases the key instance so it can be reused in the future.
	Release()
}

type ISnapshotConnection interface {
	// Close closes the ISnapshotConnection instance.
	Close()
	// SendSnapshotChunk sends the snapshot chunk to the target. It is
	// recommended to have the snapshot chunk delivered in order for the best
	// performance, but out of order delivery is allowed at the cost of reduced
	// performance.
	SendSnapshotChunk(chunk pb.SnapshotChunk) error
}

type NodeInfo struct {
	ClusterID uint64
	NodeID    uint64
}

type RaftState struct {
	// State is the Raft state persistent to the disk
	State *pb.State
	// FirstIndex is the index of the first entry to iterate
	FirstIndex uint64
	// EntryCount is the number of entries to iterate
	EntryCount uint64
}

type RequestHandler func(req pb.MessageBatch)