wangjia
49 lines
1.2 KiB
Go
49 lines
1.2 KiB
Go
package accounts
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import (
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"hash/fnv"
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"github.com/wangjia/pay/config"
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)
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// Weighted 按 Weight 加权选账户,决策源为 hash(OutTradeNo)(确定性、可复现、跨节点一致,
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// 见计划 D1)。Weight<=0 记 1(对齐 model.Account gorm default:1)。retry 换号由
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// Router 的 ExcludeAccounts 过滤驱动,不依赖随机。
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type Weighted struct{}
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func NewWeighted() *Weighted { return &Weighted{} }
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func (Weighted) Pick(_ string, candidates []config.AccountConfig, hint PickHint) (config.AccountConfig, error) {
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if len(candidates) == 0 {
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return config.AccountConfig{}, ErrNoAccount
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}
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if hint.OutTradeNo == "" {
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return candidates[0], nil
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}
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var total uint32
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for _, c := range candidates {
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total += weightOf(c)
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}
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if total == 0 { // 理论不达(weightOf>=1),兜底
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return candidates[0], nil
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}
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h := fnv.New32a()
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_, _ = h.Write([]byte(hint.OutTradeNo))
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target := h.Sum32() % total
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var acc uint32
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for _, c := range candidates {
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acc += weightOf(c)
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if target < acc {
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return c, nil
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}
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}
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return candidates[len(candidates)-1], nil // 浮点无关的整数走位,兜底不达
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}
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func weightOf(c config.AccountConfig) uint32 {
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if c.Weight <= 0 {
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return 1
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}
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return uint32(c.Weight)
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}
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