40 lines
1.0 KiB
Go
40 lines
1.0 KiB
Go
package dao
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import (
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"context"
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"go-common/app/service/main/ugcpay-rank/internal/conf"
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"go-common/library/cache/memcache"
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)
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// CASCacheElecPrepRank cas的方式存储预备榜单，防止分布式脏写
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func (d *Dao) CASCacheElecPrepRank(c context.Context, val interface{}, rawItem *memcache.Item) (ok bool, err error) {
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var (
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conn = d.mc.Get(c)
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)
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defer conn.Close()
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rawItem.Object = val
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rawItem.Expiration = conf.Conf.CacheTTL.ElecPrepAVRankTTL
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rawItem.Flags = memcache.FlagProtobuf
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if err = conn.CompareAndSwap(rawItem); err != nil {
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if err == memcache.ErrCASConflict { // CAS冲突, 则返回ok == false, 准备重试
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err = nil
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return
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}
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if err == memcache.ErrNotStored { // 如果CAS中恰好失效，尝试Add
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if err = conn.Add(rawItem); err != nil {
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if err == memcache.ErrNotStored { // 在Add时恰好又被其他实例Add过, 则返回ok == false, 准备重试
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err = nil
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return
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}
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return // 在Add时发生未知错误
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}
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}
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return // 在CAS时发生未知错误
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}
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ok = true
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return
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}
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