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mdb/kvstore/sync-recv.go

94 lines
2.0 KiB
Go

package kvstore
import (
"encoding/binary"
"log"
"net"
"time"
)
func (kv *KV) SyncRecv(conn net.Conn) {
defer conn.Close()
if kv.primary {
panic("SyncRecv called on primary.")
}
if !kv.recvLock.TryLock() {
return
}
defer kv.recvLock.Unlock()
// It's important that we stop when this routine exits so that
// all queued writes are committed to the database before syncing
// has a chance to restart.
//kv.startWriteLoop()
//defer kv.stopWriteLoop()
w := newWriter(kv.db)
w.Start(kv.MaxSeqNum())
defer w.Stop()
headerBuf := make([]byte, recHeaderSize)
buf := make([]byte, 8)
afterSeqNum := kv.MaxSeqNum()
expectedSeqNum := afterSeqNum + 1
// Send fromID to the conn.
conn.SetWriteDeadline(time.Now().Add(connTimeout))
binary.LittleEndian.PutUint64(buf, afterSeqNum)
if _, err := conn.Write(buf); err != nil {
log.Printf("RecvWAL failed to send after sequence number: %v", err)
return
}
conn.SetWriteDeadline(time.Time{})
for {
conn.SetReadDeadline(time.Now().Add(connTimeout))
if _, err := conn.Read(headerBuf); err != nil {
log.Printf("RecvWAL failed to read header: %v", err)
return
}
rec, colLen, dataLen := decodeRecHeader(headerBuf)
// Heartbeat.
if rec.SeqNum == 0 {
continue
}
if rec.SeqNum != expectedSeqNum {
log.Printf("Expected sequence number %d but got %d.",
expectedSeqNum, rec.SeqNum)
return
}
expectedSeqNum++
if cap(buf) < colLen {
buf = make([]byte, colLen)
}
buf = buf[:colLen]
if _, err := conn.Read(buf); err != nil {
log.Printf("RecvWAL failed to read collection name: %v", err)
return
}
rec.Collection = string(buf)
if rec.Store {
rec.Data = make([]byte, dataLen)
if _, err := conn.Read(rec.Data); err != nil {
log.Printf("RecvWAL failed to read data: %v", err)
return
}
w.StoreAsync(rec.Collection, rec.ID, rec.Data)
kv.onStore(rec.Collection, rec.ID, rec.Data)
} else {
w.DeleteAsync(rec.Collection, rec.ID)
kv.onDelete(rec.Collection, rec.ID)
}
}
}