mirror of
https://github.com/tim-beatham/smegmesh.git
synced 2024-12-13 01:50:53 +01:00
145 lines
2.9 KiB
Go
145 lines
2.9 KiB
Go
package crdt
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/gob"
|
|
|
|
logging "github.com/tim-beatham/wgmesh/pkg/log"
|
|
)
|
|
|
|
type SyncState int
|
|
|
|
const (
|
|
PREPARE SyncState = iota
|
|
PRESENT
|
|
EXCHANGE
|
|
MERGE
|
|
FINISHED
|
|
)
|
|
|
|
// TwoPhaseSyncer is a type to sync a TwoPhase data store
|
|
type TwoPhaseSyncer struct {
|
|
manager *TwoPhaseStoreMeshManager
|
|
generateMessageFSM SyncFSM
|
|
state SyncState
|
|
mapState *TwoPhaseMapState[string]
|
|
peerMsg []byte
|
|
}
|
|
|
|
type SyncFSM map[SyncState]func(*TwoPhaseSyncer) ([]byte, bool)
|
|
|
|
func prepare(syncer *TwoPhaseSyncer) ([]byte, bool) {
|
|
var buffer bytes.Buffer
|
|
enc := gob.NewEncoder(&buffer)
|
|
|
|
err := enc.Encode(*syncer.mapState)
|
|
|
|
if err != nil {
|
|
logging.Log.WriteInfof(err.Error())
|
|
}
|
|
|
|
syncer.IncrementState()
|
|
return buffer.Bytes(), true
|
|
}
|
|
|
|
func present(syncer *TwoPhaseSyncer) ([]byte, bool) {
|
|
if syncer.peerMsg == nil {
|
|
panic("peer msg is nil")
|
|
}
|
|
|
|
var recvBuffer = bytes.NewBuffer(syncer.peerMsg)
|
|
dec := gob.NewDecoder(recvBuffer)
|
|
|
|
var mapState TwoPhaseMapState[string]
|
|
err := dec.Decode(&mapState)
|
|
|
|
if err != nil {
|
|
logging.Log.WriteInfof(err.Error())
|
|
}
|
|
|
|
difference := syncer.mapState.Difference(&mapState)
|
|
|
|
var sendBuffer bytes.Buffer
|
|
enc := gob.NewEncoder(&sendBuffer)
|
|
enc.Encode(*difference)
|
|
|
|
syncer.IncrementState()
|
|
return sendBuffer.Bytes(), true
|
|
}
|
|
|
|
func exchange(syncer *TwoPhaseSyncer) ([]byte, bool) {
|
|
if syncer.peerMsg == nil {
|
|
panic("peer msg is nil")
|
|
}
|
|
|
|
var recvBuffer = bytes.NewBuffer(syncer.peerMsg)
|
|
dec := gob.NewDecoder(recvBuffer)
|
|
|
|
var mapState TwoPhaseMapState[string]
|
|
dec.Decode(&mapState)
|
|
|
|
snapshot := syncer.manager.store.SnapShotFromState(&mapState)
|
|
|
|
var sendBuffer bytes.Buffer
|
|
enc := gob.NewEncoder(&sendBuffer)
|
|
enc.Encode(*snapshot)
|
|
|
|
syncer.IncrementState()
|
|
return sendBuffer.Bytes(), true
|
|
}
|
|
|
|
func merge(syncer *TwoPhaseSyncer) ([]byte, bool) {
|
|
if syncer.peerMsg == nil {
|
|
panic("peer msg is nil")
|
|
}
|
|
|
|
var recvBuffer = bytes.NewBuffer(syncer.peerMsg)
|
|
dec := gob.NewDecoder(recvBuffer)
|
|
|
|
var snapshot TwoPhaseMapSnapshot[string, MeshNode]
|
|
dec.Decode(&snapshot)
|
|
|
|
syncer.manager.store.Merge(snapshot)
|
|
return nil, false
|
|
}
|
|
|
|
func (t *TwoPhaseSyncer) IncrementState() {
|
|
t.state = min(t.state+1, FINISHED)
|
|
}
|
|
|
|
func (t *TwoPhaseSyncer) GenerateMessage() ([]byte, bool) {
|
|
fsmFunc, ok := t.generateMessageFSM[t.state]
|
|
|
|
if !ok {
|
|
panic("state not handled")
|
|
}
|
|
|
|
return fsmFunc(t)
|
|
}
|
|
|
|
func (t *TwoPhaseSyncer) RecvMessage(msg []byte) error {
|
|
t.peerMsg = msg
|
|
return nil
|
|
}
|
|
|
|
func (t *TwoPhaseSyncer) Complete() {
|
|
logging.Log.WriteInfof("SYNC COMPLETED")
|
|
t.manager.store.Clock.IncrementClock()
|
|
}
|
|
|
|
func NewTwoPhaseSyncer(manager *TwoPhaseStoreMeshManager) *TwoPhaseSyncer {
|
|
var generateMessageFsm SyncFSM = SyncFSM{
|
|
PREPARE: prepare,
|
|
PRESENT: present,
|
|
EXCHANGE: exchange,
|
|
MERGE: merge,
|
|
}
|
|
|
|
return &TwoPhaseSyncer{
|
|
manager: manager,
|
|
state: PREPARE,
|
|
mapState: manager.store.GenerateMessage(),
|
|
generateMessageFSM: generateMessageFsm,
|
|
}
|
|
}
|