ekuiper-new/pkg/kv/kv.go

// Copyright 2021 EMQ Technologies Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package kv

import (
	"sync"
)

type kvstores struct {
	stores map[string]KeyValue
	mu	   sync.Mutex
}

var stores = kvstores{
	stores: make(map[string]KeyValue),
	mu: sync.Mutex{},
}

var database Database

type KeyValue interface {
	// Set key to hold string value if key does not exist otherwise return an error
	Setnx(key string, value interface{}) error
	// Set key to hold the string value. If key already holds a value, it is overwritten
	Set(key string, value interface{}) error
	Get(key string, val interface{}) (bool, error)
	//Must return *common.Error with NOT_FOUND error
	Delete(key string) error
	Keys() (keys []string, err error)
	Clean() error
}

func SetKVStoreDatabase(d Database) {
	database = d
}

func (s *kvstores) get(table string) (error, KeyValue) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if store, contains := s.stores[table]; contains {
		return nil, store
	}
	err, store := CreateSqlKvStore(database, table)
	if err != nil {
		return err, nil
	}
	s.stores[table] = store
	return nil, store
}

func GetKVStore(table string) (error, KeyValue) {
	return stores.get(table)
}