refactor(relay): improve channel locking and retry logic in RelayTask

- Enhanced the RelayTask function to utilize a locked channel when available, allowing for better reuse during retries.
- Updated error handling to ensure proper context setup for the selected channel.
- Clarified comments in ResolveOriginTask regarding channel locking and retry behavior.
- Introduced a new field in TaskRelayInfo to store the locked channel object, improving type safety and reducing import cycles.

controller/relay.go

@@ -497,11 +497,24 @@ func RelayTask(c *gin.Context) {
 	}
 
 	for ; retryParam.GetRetry() <= common.RetryTimes; retryParam.IncreaseRetry() {
-		channel, channelErr := getChannel(c, relayInfo, retryParam)
-		if channelErr != nil {
-			logger.LogError(c, channelErr.Error())
-			taskErr = service.TaskErrorWrapperLocal(channelErr.Err, "get_channel_failed", http.StatusInternalServerError)
-			break
+		var channel *model.Channel
+
+		if lockedCh, ok := relayInfo.LockedChannel.(*model.Channel); ok && lockedCh != nil {
+			channel = lockedCh
+			if retryParam.GetRetry() > 0 {
+				if setupErr := middleware.SetupContextForSelectedChannel(c, channel, relayInfo.OriginModelName); setupErr != nil {
+					taskErr = service.TaskErrorWrapperLocal(setupErr.Err, "setup_locked_channel_failed", http.StatusInternalServerError)
+					break
+				}
+			}
+		} else {
+			var channelErr *types.NewAPIError
+			channel, channelErr = getChannel(c, relayInfo, retryParam)
+			if channelErr != nil {
+				logger.LogError(c, channelErr.Error())
+				taskErr = service.TaskErrorWrapperLocal(channelErr.Err, "get_channel_failed", http.StatusInternalServerError)
+				break
+			}
 		}
 
 		addUsedChannel(c, channel.Id)