feat(relay): add in-memory adaptive circuit breaker and auto-fallback retry mechanism

model/channel_cache.go

@@ -112,6 +112,10 @@ func SyncChannelCache(frequency int) {
 }
 
 func GetRandomSatisfiedChannel(group string, model string, retry int, requestPath string) (*Channel, error) {
+	return GetRandomSatisfiedChannelWithExcluded(group, model, retry, requestPath, nil)
+}
+
+func GetRandomSatisfiedChannelWithExcluded(group string, model string, retry int, requestPath string, excludedIDs []int) (*Channel, error) {
 	// if memory cache is disabled, get channel directly from database
 	if !common.MemoryCacheEnabled {
 		return GetChannel(group, model, retry, requestPath)
@@ -129,6 +133,21 @@ func GetRandomSatisfiedChannel(group string, model string, retry int, requestPat
 		channels = filterChannelsByRequestPathAndModel(group2model2channels[group][normalizedModel], requestPath, model)
 	}
 
+	// Filter out excluded channels (channels that already failed in the current request)
+	if len(excludedIDs) > 0 && len(channels) > 0 {
+		excludedMap := make(map[int]bool, len(excludedIDs))
+		for _, id := range excludedIDs {
+			excludedMap[id] = true
+		}
+		filtered := make([]int, 0, len(channels))
+		for _, id := range channels {
+			if !excludedMap[id] {
+				filtered = append(filtered, id)
+			}
+		}
+		channels = filtered
+	}
+
 	if len(channels) == 0 {
 		return nil, nil
 	}