From 82d34c0a71f05f9b238634b570435f819b04529d Mon Sep 17 00:00:00 2001
From: Amit Roushan <amit.roushan@huawei.com>
Date: Thu, 2 Sep 2021 22:25:52 +0530
Subject: [PATCH] added code changes for protocol topological awarness

---
 src/csi/backend/backend.go     | 80 +++++++++++++++++++++++++---------
 src/csi/main.go                |  4 +-
 src/utils/k8sutils/k8sutils.go |  3 +-
 3 files changed, 63 insertions(+), 24 deletions(-)

diff --git a/src/csi/backend/backend.go b/src/csi/backend/backend.go
index 314f0b58..83996f90 100644
--- a/src/csi/backend/backend.go
+++ b/src/csi/backend/backend.go
@@ -9,6 +9,7 @@ import (
 	"sync"
 	"utils"
 	"utils/log"
+	"utils/k8sutils"
 )
 
 const (
@@ -122,26 +123,10 @@ func newBackend(backendName string, config map[string]interface{}) (*Backend, er
 		return nil, errors.New("parameters must be configured for backend")
 	}
 
-	supportedTopologies := make([]map[string]string, 0)
-	if topologies, exist := config[SupportedTopologies]; exist {
-		topologyArray, ok := topologies.([]interface{})
-		if !ok {
-			return nil, errors.New("invalid supported topologies configuration")
-		}
-		for _, topologyArrElem := range topologyArray {
-			topologyMap, ok := topologyArrElem.(map[string]interface{})
-			if !ok {
-				return nil, errors.New("invalid supported topologies configuration")
-			}
-			tempMap := make(map[string]string, 0)
-			for topologyKey, value := range topologyMap {
-				if topologyValue, ok := value.(string); ok {
-					tempMap[topologyKey] = topologyValue
-				}
-			}
-
-			supportedTopologies = append(supportedTopologies, tempMap)
-		}
+	// Get supported topologies for backend
+	supportedTopologies, err := getSupportedTopologies(config)
+	if err != nil {
+		return nil, err
 	}
 
 	plugin := plugin.GetPlugin(storage)
@@ -174,6 +159,47 @@ func newBackend(backendName string, config map[string]interface{}) (*Backend, er
 	}, nil
 }
 
+func getSupportedTopologies(config map[string]interface{}) ([]map[string]string, error) {
+	supportedTopologies := make([]map[string]string, 0)
+	if topologies, exist := config[SupportedTopologies]; exist {
+		// populate configured topologies
+		topologyArray, ok := topologies.([]interface{})
+		if !ok {
+			return nil, errors.New("invalid supported topologies configuration")
+		}
+		for _, topologyArrElem := range topologyArray {
+			topologyMap, ok := topologyArrElem.(map[string]interface{})
+			if !ok {
+				return nil, errors.New("invalid supported topologies configuration")
+			}
+			tempMap := make(map[string]string, 0)
+			for topologyKey, value := range topologyMap {
+				if topologyValue, ok := value.(string); ok {
+					tempMap[topologyKey] = topologyValue
+				}
+			}
+
+			supportedTopologies = append(supportedTopologies, tempMap)
+		}
+	}
+
+	return supportedTopologies, nil
+}
+
+// addProtocolTopology add up protocol specific topological support
+func addProtocolTopology(backend *Backend, driverName string){
+	proto, protocolAvailable := backend.Parameters["protocol"]
+	if protocol, isString := proto.(string); protocolAvailable && isString {
+		backend.SupportedTopologies = append(backend.SupportedTopologies, map[string]string{
+			k8sutils.TopologyPrefix + "/protocol." + protocol: driverName,
+		})
+		return
+	}
+
+	log.Warningf("supported topology for protocol may not work as protocol is miss configured " +
+		"in backend configuration")
+}
+
 func analyzeBackend(config map[string]interface{}) (*Backend, error) {
 	backendName, exist := config["name"].(string)
 	if !exist {
@@ -245,7 +271,7 @@ func updateReplicaBackends() {
 	}
 }
 
-func RegisterBackend(backendConfigs []map[string]interface{}, keepLogin bool) error {
+func RegisterBackend(backendConfigs []map[string]interface{}, keepLogin bool, driverName string) error {
 	for _, i := range backendConfigs {
 		backend, err := analyzeBackend(i)
 		if err != nil {
@@ -259,6 +285,18 @@ func RegisterBackend(backendConfigs []map[string]interface{}, keepLogin bool) er
 			return err
 		}
 
+		// Note: Protocol is considered as special topological parameter. The protocol topology
+		// 		is populated internally by plugin using protocol name.
+		//		If configured protocol for backend is "iscsi", CSI plugin internally add
+		//		topology.kubernetes.io/protocol.iscsi = csi.huawei.com in supportedTopologies.
+		//
+		//		Now users can opt to provision volumes based on protocol by
+		//		1. Labeling kubernetes nodes with protocol specific label (ie topology.kubernetes.io/protocol.iscsi = csi.huawei.com)
+		//		2. Configure topology support in plugin
+		//		3. Configure protocol topology in allowedTopologies fo Storage class
+		// addProtocolTopology is called after backend plugin init as init takes care of protocol validation
+		addProtocolTopology(backend, driverName)
+
 		csiBackends[backend.Name] = backend
 	}
 
diff --git a/src/csi/main.go b/src/csi/main.go
index 5f781d14..8f819f65 100644
--- a/src/csi/main.go
+++ b/src/csi/main.go
@@ -182,14 +182,14 @@ func main() {
 	}()
 
 	if *controller || *controllerFlagFile != "" {
-		err := backend.RegisterBackend(config.Backends, true)
+		err := backend.RegisterBackend(config.Backends, true, *driverName)
 		if err != nil {
 			log.Fatalf("Register backends error: %v", err)
 		}
 
 		go updateBackendCapabilities()
 	} else {
-		err := backend.RegisterBackend(config.Backends, false)
+		err := backend.RegisterBackend(config.Backends, false, *driverName)
 		if err != nil {
 			log.Fatalf("Register backends error: %v", err)
 		}
diff --git a/src/utils/k8sutils/k8sutils.go b/src/utils/k8sutils/k8sutils.go
index dff1deac..08c2b6fc 100644
--- a/src/utils/k8sutils/k8sutils.go
+++ b/src/utils/k8sutils/k8sutils.go
@@ -13,7 +13,8 @@ import (
 )
 
 const (
-	topologyRegx = "topology.kubernetes.io/*"
+	TopologyPrefix = "topology.kubernetes.io"
+	topologyRegx = TopologyPrefix + "/.*"
 )
 
 type Interface interface {