73 lines
2.0 KiB
Go
73 lines
2.0 KiB
Go
package worker
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import (
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"context"
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"errors"
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"fmt"
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"goRedisDLM/engine"
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"goRedisDLM/redisLock"
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"log"
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"strconv"
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"github.com/go-redis/redis/v8"
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)
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type Inventory struct {
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Client *redis.Client
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}
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func (i *Inventory) Work(request engine.Request, response *engine.Response) error {
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ctx := context.Background()
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//lock := redisLock.CreateRedisLock(i.Client, ctx, request.Dlock, 100)
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lock := redisLock.NewRedisLock(i.Client, ctx, "test_key", redisLock.WithBlock(),
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redisLock.WithMaxWaitTime(20), redisLock.WithExpireTime(5))
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lock.Lock()
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//time.Sleep(time.Duration(rand.Int31n(100)) * time.Millisecond)
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get := i.Client.Get(ctx, "inventory")
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log.Printf("%s\n", get)
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inventory, err := strconv.Atoi(get.Val())
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if err != nil {
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goto Error
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}
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inventory = inventory - 1
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if inventory >= 0 {
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//这里应该使用lua脚本，再检测一下当前是否获取到锁，获取到之后再进行扣减。类似双检加锁的思想，因为此时可能会续期失败。
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//i.Client.Set(ctx, "inventory", fmt.Sprintf("%d", inventory), redis.KeepTTL)
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//script := `if redis.call('hexists',KEYS[1],ARGV[1]) == 1 then return redis.call('set',KEYS[2],ARGV[2])
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// else return 0 end`
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//
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//val := i.Client.Eval(ctx, script, []string{request.Dlock, "inventory"}, value.String(), inventory).Val()
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if lock.IsHeldByCurrent() {
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setString := fmt.Sprintf("%d", inventory)
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if i.Client.Set(ctx, "inventory", setString, redis.KeepTTL).Val() != "OK" {
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log.Println("error set inventory")
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err = errors.New("inventory err")
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goto Error
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}
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} else {
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//任务执行失败需要通知调用者，让调用者自己决策是否需要重新调度还是放弃，这样worker和主线程实现了解偶
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log.Println("error lock is not held")
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err = errors.New("error lock is not held")
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goto Error
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}
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} else {
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log.Printf("error DLock error :%d\n", inventory)
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err = errors.New("inventory err")
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goto Error
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}
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lock.UnLock()
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response.Id = request.Id
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return nil
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Error:
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lock.UnLock()
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return err
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}
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