snippet.md

func (a *UpgradeGatewayAPIV1) runCluster() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		clientNodes, _ := connector.AgentClients(r.Context())
		
		// filter out cluster delegate and non-delegate nodes
		var clusterDelegateNode *catalog.Agent
		var nonDelegateNodes []*catalog.Agent
		for _, node := range clientNodes {
			if node.ClusterAttrs.ClusterDelegate{
				clusterDelegateNode = node
			} else {
				nonDelegateNodes = append(nonDelegateNodes, node)
			}
		}

		ctx := r.Context()
		// trigger upgrade on non-delegate nodes
		response := externalds.ForEachAsync(clientNodes, func(node *catalog.Agent) RunResponse {
			node.UpgradeClient().Run(ctx, &upgradegen.RunRequest{
				UpgradePackageFile: "",
				Version:            "3.22.0",
				SkipReboot:         false,
			})
		 })

		// check for upgrade status on non-delegate nodes. It takes 3-4 min for the process above to finish
		runFinished := false
		for !runFinished {
			time.Sleep(5 * time.Second)
			response = clusterDelegateNode.UpgradeClient().GetStatus();
			runFinished = true
			for r := range response {
				if r.UUID == clusterDelegateNode.ClusterAttrs.Uuid {
					continue
				}
				if r.OverallStatus == FAILED {
					//handle failure case and toleate reboot error
					runFinished = false
				}
				if r.OverallStatus != COMPLETED {
					runFinished = false
				}
			}
			// trigger upgrade on cluster delegate nodes
			if runFinished{
				clusterDelegateNode.UpgradeClient().Run(ctx, &upgradegen.RunRequest{
					UpgradePackageFile: "",
					Version:            "3.22.0",
					SkipReboot:         false,
				})
			}
		}
	}
}