redies dict字典
这是 Redis 最底层的结构，比如 1个DB 下面有 16个Dict
1. 使用接口方式， 基础实现是simple_dict ,sync_dict ,后续用户可以根据自己的需求进行自定义的实现属于自己的Dict , 在 forEach 方法 支持匿名函数方式
type Dict interface {
Get(key string) (val interface {}, exists bool)
Len()
// 回复上次 put 放入
Put(key string, val interface{}) (result int)
PutIfAbsent(key string, val interface {}) (result int)
PutIfExists(key string, val interface{}) (result int)
Remove(key string) (result int)
ForEach(consumer Consumer) // 传入是方法， 返回 bool = true j继续遍历
Keys() []string
RandomKeys(limit int) []string
// 返回多个不重复的键
RandomDistinctKeys(limit int) []string
Clear()
}
// Consumer is used to traversal dict, if it returns false the traversal will be break
type Consumer func(key string, val interface{}) bool
package dict
// SimpleDict wraps a map, it is not thread safe
type SimpleDict struct {
m map[string]interface{}
}
// MakeSimple makes a new map
func MakeSimple() *SimpleDict {
return &SimpleDict{
m: make(map[string]interface{}),
}
}
// Get returns the binding value and whether the key is exist
func (dict *SimpleDict) Get(key string) (val interface{}, exists bool) {
val, ok := dict.m[key]
return val, ok
}
// Len returns the number of dict
func (dict *SimpleDict) Len() int {
if dict.m == nil {
panic("m is nil")
}
return len(dict.m)
}
// Put puts key value into dict and returns the number of new inserted key-value
func (dict *SimpleDict) Put(key string, val interface{}) (result int) {
_, existed := dict.m[key]
dict.m[key] = val
if existed {
return 0
}
return 1
}
// PutIfAbsent puts value if the key is not exists and returns the number of updated key-value
func (dict *SimpleDict) PutIfAbsent(key string, val interface{}) (result int) {
_, existed := dict.m[key]
if existed {
return 0
}
dict.m[key] = val
return 1
}
// PutIfExists puts value if the key is exist and returns the number of inserted key-value
func (dict *SimpleDict) PutIfExists(key string, val interface{}) (result int) {
_, existed := dict.m[key]
if existed {
dict.m[key] = val
return 1
}
return 0
}
// Remove removes the key and return the number of deleted key-value
func (dict *SimpleDict) Remove(key string) (result int) {
_, existed := dict.m[key]
delete(dict.m, key)
if existed {
return 1
}
return 0
}
// Keys returns all keys in dict
func (dict *SimpleDict) Keys() []string {
result := make([]string, len(dict.m))
i := 0
for k := range dict.m {
result = k
}
return result
}
// ForEach traversal the dict
func (dict *SimpleDict) ForEach(consumer Consumer) {
for k, v := range dict.m {
if !consumer(k, v) {
break
}
}
}
// RandomKeys randomly returns keys of the given number, may contain duplicated key
func (dict *SimpleDict) RandomKeys(limit int) []string {
result := make([]string, limit)
for i := 0; i < limit; i++ {
for k := range dict.m {
result = k
break
}
}
return result
}
// RandomDistinctKeys randomly returns keys of the given number, won't contain duplicated key
func (dict *SimpleDict) RandomDistinctKeys(limit int) []string {
size := limit
if size > len(dict.m) {
size = len(dict.m)
}
result := make([]string, size)
i := 0
for k := range dict.m {
if i == limit {
break
}
result = k
i++
}
return result
}
// Clear removes all keys in dict
func (dict *SimpleDict) Clear() {
*dict = *MakeSimple()
}
Redis的DB实现
针对其中 Command 的实现， ping, set ,Get 有具体的实现方法， 采用策略模式形式， 不同的方法 有自己的 Executor 执行器
// 指令与结构体之间的关系
var cmdTable = make(map[string]*command)
type command struct {
executor ExecFunc
arity int // allow number of args, arity < 0 means len(args) >= -arity
}
// RegisterCommand registers a new command
// arity means allowed number of cmdArgs, arity < 0 means len(args) >= -arity.
// for example: the arity of `get` is 2, `mget` is -2
func RegisterCommand(name string, executor ExecFunc, arity int) {
name = strings.ToLower(name)
cmdTable[name] = &command{
executor: executor,
arity: arity,
}
}
// Package database is a memory database with redis compatible interface
package database
import (
"go-redis/datastruct/dict"
"go-redis/interface/database"
"go-redis/interface/resp"
"go-redis/resp/reply"
"strings"
)
// DB stores data and execute user's commands
type DB struct {
index int
// key -> DataEntity
data dict.Dict // 底层的实现可以进行切换
}
// ExecFunc is interface for command executor, redis 的 指令实现, 所有的实现 协程这种形式
// args don't include cmd line
type ExecFunc func(db *DB, args [][]byte) resp.Reply
// CmdLine is alias for [][]byte, represents a command line
type CmdLine = [][]byte
// makeDB create DB instance
func makeDB() *DB {
db := &DB{
data: dict.MakeSyncDict(), // 使用的 sync 的 dict
}
return db
}
// Exec executes command within one database
func (db *DB) Exec(c resp.Connection, cmdLine [][]byte) resp.Reply {
cmdName := strings.ToLower(string(cmdLine[0]))
cmd, ok := cmdTable[cmdName]
if !ok {
return reply.MakeErrReply("ERR unknown command '" + cmdName + "'")
}
if !validateArity(cmd.arity, cmdLine) {
return reply.MakeArgNumErrReply(cmdName)
}
fun := cmd.executor
return fun(db, cmdLine[1:])
}
func validateArity(arity int, cmdArgs [][]byte) bool {
argNum := len(cmdArgs)
if arity >= 0 {
return argNum == arity
}
return argNum >= -arity
}
/* ---- data Access ----- */
// GetEntity returns DataEntity bind to given key
func (db *DB) GetEntity(key string) (*database.DataEntity, bool) {
raw, ok := db.data.Get(key)
if !ok {
return nil, false
}
entity, _ := raw.(*database.DataEntity)
return entity, true
}
// PutEntity a DataEntity into DB
func (db *DB) PutEntity(key string, entity *database.DataEntity) int {
return db.data.Put(key, entity)
}
// PutIfExists edit an existing DataEntity
func (db *DB) PutIfExists(key string, entity *database.DataEntity) int {
return db.data.PutIfExists(key, entity)
}
// PutIfAbsent insert an DataEntity only if the key not exists
func (db *DB) PutIfAbsent(key string, entity *database.DataEntity) int {
return db.data.PutIfAbsent(key, entity)
}
// Remove the given key from db
func (db *DB) Remove(key string) {
db.data.Remove(key)
}
// Removes the given keys from db
func (db *DB) Removes(keys ...string) (deleted int) {
deleted = 0
for _, key := range keys {
_, exists := db.data.Get(key)
if exists {
db.Remove(key)
deleted++
}
}
return deleted
}
// Flush clean database
func (db *DB) Flush() {
db.data.Clear()
}
具体的实现器
// Ping Executor
func Ping(db *DB, args [][]byte) resp.Reply {
if len(args) == 0 {
return &reply.PongReply{}
} else if len(args) == 1 {
return reply.MakeStatusReply(string(args[0]))
} else {
return reply.MakeErrReply("ERR wrong number of arguments for 'ping' command")
}
}
// 初始化 方法
func init() {
RegisterCommand("ping", Ping, -1)
}
Redis持久化Aof
AOF 则以协议文本的方式，将所有对数据库进行过写入的命令（及其参数）记录到 AOF 文件，以此达到记录数据库状态的目的.
package aof
import (
"go-redis/config"
databaseface "go-redis/interface/database"
"go-redis/lib/logger"
"go-redis/lib/utils"
"go-redis/resp/connection"
"go-redis/resp/parser"
"go-redis/resp/reply"
"io"
"os"
"strconv"
)
// CmdLine is alias for [][]byte, represents a command line
type CmdLine = [][]byte
const (
aofQueueSize = 1 << 16
)
type payload struct {
cmdLine CmdLine
dbIndex int
}
// AofHandler receive msgs from channel and write to AOF file
type AofHandler struct {
db databaseface.Database
aofChan chan *payload
aofFile *os.File
aofFilename string
currentDB int
}
// NewAOFHandler creates a new aof.AofHandler
func NewAOFHandler(db databaseface.Database) (*AofHandler, error) {
handler := &AofHandler{}
handler.aofFilename = config.Properties.AppendFilename
handler.db = db
// init Load Aof to Memory
handler.LoadAof()
aofFile, err := os.OpenFile(handler.aofFilename, os.O_APPEND|os.O_CREATE|os.O_RDWR, 0600)
if err != nil {
return nil, err
}
handler.aofFile = aofFile
handler.aofChan = make(chan *payload, aofQueueSize)
go func() {
handler.handleAof()
}()
return handler, nil
}
func (handler *AofHandler) AddAof(dbIndex int, cmdLine CmdLine) {
if config.Properties.AppendOnly && handler.aofChan != nil {
handler.aofChan <- &payload{
cmdLine: cmdLine,
dbIndex: dbIndex,
}
}
}
// LoadAof read aof file 数据回放的功能
func (handler *AofHandler) LoadAof() {
file, err := os.Open(handler.aofFilename)
if err != nil {
logger.Warn(err)
return
}
defer func(file *os.File) {
err := file.Close()
if err != nil {
}
}(file)
ch := parser.ParseStream(file)
fakeConn := &connection.Connection{} // only used for save dbIndex
// LoadAof recover data
for p := range ch {
if p.Err != nil {
if p.Err == io.EOF {
break
}
logger.Error("parse error: " + p.Err.Error())
continue
}
if p.Data == nil {
logger.Error("empty payload")
continue
}
r, ok := p.Data.(*reply.MultiBulkReply)
if !ok {
logger.Error("require multi bulk reply")
continue
}
ret := handler.db.Exec(fakeConn, r.Args)
if reply.IsErrorReply(ret) {
logger.Error("exec err", err)
}
}
}
// handleAof listen aof channel and write into file aof 异步形式的落盘
func (handler *AofHandler) handleAof() {
handler.currentDB = 0
for p := range handler.aofChan {
if p.dbIndex != handler.currentDB {
// select db
data := reply.MakeMultiBulkReply(utils.ToCmdLine("SELECT", strconv.Itoa(p.dbIndex))).ToBytes()
_, err := handler.aofFile.Write(data)
if err != nil {
logger.Warn(err)
continue // skip this command
}
handler.currentDB = p.dbIndex
}
data := reply.MakeMultiBulkReply(p.cmdLine).ToBytes()
_, err := handler.aofFile.Write(data)
if err != nil {
logger.Warn(err)
}
}
}
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发表于 2025-3-12 11:56:33