paxosio

type ChunkSinkFactory func() IChunkSink

type IChunkSink interface {
	// Close closes the sink instance and releases all resources held by it.
	Close()

	// 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 paxospb.MessageBatch) error
}

type IContext interface {
	Destroy()
	Reset()
	GetKey() IReusableKey
	GetValueBuffer(sz uint64) []byte
	GetUpdates() []paxospb.Update
	GetWriteBatch() interface{}
}

type ILogDB interface {
	Name() string
	Close()
	GetLogDBThreadContext() IContext
	ListNodeInfo() ([]NodeInfo, error)

	// SaveBootstrapInfo saves the specified bootstrap info to the log DB.
	SaveBootstrapInfo(groupID uint64,
		nodeID uint64, bootstrap paxospb.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(groupID uint64, nodeID uint64) (*paxospb.Bootstrap, error)
	SavePaxosState(updates []paxospb.Update, ctx IContext) error

	// IterateEntries returns the continuous Paxos log entries of the specified
	// Paxos 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(groupID uint64, nodeID uint64, low uint64,
		high uint64) ([]paxospb.Entry, error)

	// ReadPaxosState returns the persistented paxos state found in Log DB.
	ReadPaxosState(groupID, nodeID, lastInstance uint64) (*PaxosState, error)
}

type IPaxosRPC interface {
	Name() string
	Start() error
	Stop()
	// GetConnection returns an IConnection instance responsible for
	// sending Raft messages to the specified target nodehost.
	GetConnection(ctx context.Context, target string) (IConnection, error)
}

type IReusableKey interface {
	SetEntryBatchKey(groupID uint64, nodeID uint64, index uint64)
	// SetEntryKey sets the key to be an entry key for the specified paxos node
	// with the specified entry index.
	SetEntryKey(clustergroupIDID uint64, nodeID uint64, index uint64)
	// SetStateKey sets the key to be an persistent state key suitable
	// for the specified paxos group node.
	SetStateKey(groupID uint64, nodeID uint64)
	// SetMaxInstanceKey sets the key to be the max possible index key for the
	// specified paxos group node.
	SetMaxInstanceKey(groupID 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 NodeInfo struct {
	GroupID uint64
	NodeID  uint64
}

type PaxosState struct {
	State *paxospb.State
	// FirstInstanceID is the index of the first entry to iterate
	FirstInstanceID uint64
	// EntryCount is the number of entries to iterate
	EntryCount uint64
}

type RequestHandler func(req paxospb.MessageBatch)

type State struct {
	InstanceID uint64
	Commit     uint64
}