feat: switch priority when retry (close #1048)

common/random.go

@@ -0,0 +1,8 @@
+package common
+
+import "math/rand"
+
+// RandRange returns a random number between min and max (max is not included)
+func RandRange(min, max int) int {
+	return min + rand.Intn(max-min)
+}

controller/relay.go

@@ -62,7 +62,7 @@ func Relay(c *gin.Context) {
 		retryTimes = 0
 	}
 	for i := retryTimes; i > 0; i-- {
-		channel, err := dbmodel.CacheGetRandomSatisfiedChannel(group, originalModel)
+		channel, err := dbmodel.CacheGetRandomSatisfiedChannel(group, originalModel, true)
 		if err != nil {
 			logger.Errorf(ctx, "CacheGetRandomSatisfiedChannel failed: %w", err)
 			break

middleware/distributor.go

@@ -68,7 +68,7 @@ func Distribute() func(c *gin.Context) {
 				}
 			}
 			requestModel = modelRequest.Model
-			channel, err = model.CacheGetRandomSatisfiedChannel(userGroup, modelRequest.Model)
+			channel, err = model.CacheGetRandomSatisfiedChannel(userGroup, modelRequest.Model, false)
 			if err != nil {
 				message := fmt.Sprintf("当前分组 %s 下对于模型 %s 无可用渠道", userGroup, modelRequest.Model)
 				if channel != nil {

model/cache.go

@@ -191,7 +191,7 @@ func SyncChannelCache(frequency int) {
 	}
 }
 
-func CacheGetRandomSatisfiedChannel(group string, model string) (*Channel, error) {
+func CacheGetRandomSatisfiedChannel(group string, model string, ignoreFirstPriority bool) (*Channel, error) {
 	if !config.MemoryCacheEnabled {
 		return GetRandomSatisfiedChannel(group, model)
 	}
@@ -213,5 +213,10 @@ func CacheGetRandomSatisfiedChannel(group string, model string) (*Channel, error
 		}
 	}
 	idx := rand.Intn(endIdx)
+	if ignoreFirstPriority {
+		if endIdx < len(channels) { // which means there are more than one priority
+			idx = common.RandRange(endIdx, len(channels))
+		}
+	}
 	return channels[idx], nil
 }