/
api.go
201 lines (180 loc) · 4.92 KB
/
api.go
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package main
import (
"bufio"
"context"
"encoding/json"
"fmt"
"log"
"os"
"os/exec"
"strconv"
"strings"
"sync"
"time"
cmap "github.com/orcaman/concurrent-map"
pb "github.com/ss87021456/gRPC-KVStore/proto"
)
type ServerMgr struct {
inMemoryCache cmap.ConcurrentMap
lastSnapTime int64
logLock sync.Mutex
logFile *os.File
countLock sync.Mutex
opsCount []int
mode string
}
type SharedCache []*SingleCache
type SingleCache struct {
lock sync.RWMutex
cache map[string]string
}
type JsonData struct {
Key, Value string
}
func NewServerMgr(mode string) *ServerMgr {
return &ServerMgr{inMemoryCache: cmap.New(), opsCount: make([]int, 3), mode: mode}
}
func (s *ServerMgr) Get(ctx context.Context, getReq *pb.GetRequest) (*pb.GetResponse, error) {
key := getReq.GetKey()
// log.Printf("Get key: %s", key)
val, err := getHelper(s, key)
if s.mode == "test" {
s.countLock.Lock()
s.opsCount[0]++
s.countLock.Unlock()
}
return &pb.GetResponse{Value: val}, err
}
func (s *ServerMgr) Set(ctx context.Context, setReq *pb.SetRequest) (*pb.Empty, error) {
key, value := setReq.GetKey(), setReq.GetValue()
// log.Printf("Set key: %s, value: %s", key, value)
err := writeAheadLog(s, key, value)
if err != nil {
return &pb.Empty{}, nil
}
setHelper(s, key, value)
if s.mode == "test" {
s.countLock.Lock()
s.opsCount[1]++
s.countLock.Unlock()
}
return &pb.Empty{}, nil
}
func (s *ServerMgr) GetPrefix(ctx context.Context, getPrefixReq *pb.GetPrefixRequest) (*pb.GetPrefixResponse, error) {
res := prefixHelper(s, getPrefixReq.GetKey())
// log.Printf("Get prefix: %s", getPrefixReq.GetKey())
if s.mode == "test" {
s.countLock.Lock()
s.opsCount[2]++
s.countLock.Unlock()
}
if len(res) > 0 {
return &pb.GetPrefixResponse{Values: res}, nil
}
return &pb.GetPrefixResponse{}, fmt.Errorf("No specific prefix %s found", getPrefixReq.GetKey())
}
func (s *ServerMgr) SnapShot(filename string) {
oFile, _ := os.OpenFile(filename, os.O_CREATE|os.O_WRONLY, os.ModePerm)
// clean up the file, but need to use a more efficient way
oFile.Truncate(0)
oFile.Seek(0, 0)
defer oFile.Close()
encoder := json.NewEncoder(oFile)
encoder.Encode(time.Now().Unix())
err := encoder.Encode(s.makeData())
if err != nil {
log.Printf("fail to write to file %s", err)
}
}
func (s *ServerMgr) makeData() interface{} {
datas := []map[string]interface{}{}
for m := range s.inMemoryCache.Iter() {
data := map[string]interface{}{
"Key": m.Key,
"Value": m.Val,
}
datas = append(datas, data)
}
return datas
}
func (s *ServerMgr) LoadFromSnapshot(filename string) error {
log.Printf("Initializing cache from file: %s\n", filename)
iFile, err := os.OpenFile(filename, os.O_RDONLY, os.ModePerm)
if err != nil {
log.Println("Need to create new data storage...", err)
return err
}
defer iFile.Close()
timestampByte := make([]byte, 10) // 10 : unix time length
iFile.Read(timestampByte)
timestamp, err := strconv.Atoi(fmt.Sprintf("%s", timestampByte))
if err != nil {
log.Printf("Parse timestamp encounter err: %s", err)
}
s.lastSnapTime = int64(timestamp)
iFile.Seek(10, 0)
decoder := json.NewDecoder(iFile)
// Read the array open bracket
if _, err := decoder.Token(); err != nil {
log.Fatal("Encounter wrong json format data1...", err)
return err
}
// while the array contains values
for decoder.More() {
var m JsonData
err := decoder.Decode(&m)
if err != nil {
log.Fatal("Encounter wrong json format data3...", err)
return err
}
setHelper(s, m.Key, m.Value)
}
// read closing bracket
if _, err := decoder.Token(); err != nil {
log.Fatal("Encounter wrong json format data...", err)
return err
}
log.Printf("Finish initializing cache from file: %s\n", filename)
return nil
}
func (s *ServerMgr) LoadFromHistoryLog(filename string) error {
s.logLock.Lock()
defer s.logLock.Unlock()
file, err := os.Open(filename)
if err != nil {
log.Fatal(err)
}
scanner := bufio.NewScanner(file)
buf := make([]byte, 0, 1024*1024)
scanner.Buffer(buf, 1024*1024*5)
for scanner.Scan() {
arr := strings.Split(scanner.Text(), ",")
if arr[3] == "done" { // checksum-like detection
setHelper(s, arr[1], arr[2]) // arr layout -> [timestamp, key, value]
}
}
if err := scanner.Err(); err != nil {
log.Fatal(err)
}
log.Printf("done recovery from dataset %s with size %d", filename, s.inMemoryCache.Count())
file.Close()
// log compaction
newFile, err := os.OpenFile("new.log", os.O_CREATE|os.O_WRONLY, os.ModePerm)
newFile.Truncate(0)
newFile.Seek(0, 0)
if err != nil {
log.Println("Failed to create ntemporary file: new.log", err)
}
for m := range s.inMemoryCache.Iter() {
outStr := fmt.Sprintf("%v,%s,%s,done\n", time.Now().Unix(), m.Key, m.Val)
if _, err := newFile.WriteString(outStr); err != nil {
log.Println(err)
}
}
newFile.Close()
c := exec.Command("mv", "new.log", "history.log")
if err := c.Run(); err != nil {
fmt.Println("Exec mv new.log failed: ", err)
}
return nil
}