Aligned naming for subscription. Simplify sotw server by removing unneeded part from ads/non-ads

Author: valerian-roche

pkg/cache/v3/cache.go

@@ -36,21 +36,21 @@ type Request = discovery.DiscoveryRequest
 // DeltaRequest is an alias for the delta discovery request type.
 type DeltaRequest = discovery.DeltaDiscoveryRequest
 
-// SubscriptionState stores the server view of the client state for a given resource type.
+// Subscription stores the server view of the client state for a given resource type.
 // This allows proper implementation of stateful aspects of the protocol (e.g. returning only some updated resources).
 // Though the methods may return mutable parts of the state for performance reasons,
 // the cache is expected to consider this state as immutable and thread safe between a watch creation and its cancellation.
-type SubscriptionState interface {
-	// GetACKedResources returns a list of resources that the client has ACK'd and their associated version.
+type Subscription interface {
+	// ReturnedResources returns a list of resources that clients have ACK'd and their associated version.
 	// The versions are:
 	//  - delta protocol: version of the specific resource set in the response
 	//  - sotw protocol: version of the global response when the resource was last ACKed
-	GetACKedResources() map[string]string
+	ReturnedResources() map[string]string
 
-	// GetSubscribedResources returns the list of resources currently subscribed to by the client for the type.
+	// SubscribedResources returns the list of resources currently subscribed to by the client for the type.
 	// For delta it keeps track of subscription updates across requests
 	// For sotw it is a normalized view of the last request resources
-	GetSubscribedResources() map[string]struct{}
+	SubscribedResources() map[string]struct{}
 
 	// IsWildcard returns whether the client has a wildcard watch.
 	// This considers subtleties related to the current migration of wildcard definitions within the protocol.
@@ -81,7 +81,7 @@ type ConfigWatcher interface {
 	//
 	// Cancel is an optional function to release resources in the producer. If
 	// provided, the consumer may call this function multiple times.
-	CreateWatch(*Request, SubscriptionState, chan Response) (cancel func(), err error)
+	CreateWatch(*Request, Subscription, chan Response) (cancel func(), err error)
 
 	// CreateDeltaWatch returns a new open incremental xDS watch.
 	// This is the entrypoint to propagate configuration changes the
@@ -93,7 +93,7 @@ type ConfigWatcher interface {
 	//
 	// Cancel is an optional function to release resources in the producer. If
 	// provided, the consumer may call this function multiple times.
-	CreateDeltaWatch(*DeltaRequest, SubscriptionState, chan DeltaResponse) (cancel func(), err error)
+	CreateDeltaWatch(*DeltaRequest, Subscription, chan DeltaResponse) (cancel func(), err error)
 }
 
 // ConfigFetcher fetches configuration resources from cache

pkg/cache/v3/delta.go

@@ -27,7 +27,7 @@ type resourceContainer struct {
 	systemVersion string
 }
 
-func createDeltaResponse(ctx context.Context, req *DeltaRequest, state SubscriptionState, resources resourceContainer) *RawDeltaResponse {
+func createDeltaResponse(ctx context.Context, req *DeltaRequest, state Subscription, resources resourceContainer) *RawDeltaResponse {
 	// variables to build our response with
 	var nextVersionMap map[string]string
 	var filtered []types.Resource
@@ -36,7 +36,7 @@ func createDeltaResponse(ctx context.Context, req *DeltaRequest, state Subscript
 	// If we are handling a wildcard request, we want to respond with all resources
 	switch {
 	case state.IsWildcard():
-		if len(state.GetACKedResources()) == 0 {
+		if len(state.ReturnedResources()) == 0 {
 			filtered = make([]types.Resource, 0, len(resources.resourceMap))
 		}
 		nextVersionMap = make(map[string]string, len(resources.resourceMap))
@@ -45,25 +45,25 @@ func createDeltaResponse(ctx context.Context, req *DeltaRequest, state Subscript
 			// we can just set it here to be used for comparison later
 			version := resources.versionMap[name]
 			nextVersionMap[name] = version
-			prevVersion, found := state.GetACKedResources()[name]
+			prevVersion, found := state.ReturnedResources()[name]
 			if !found || (prevVersion != version) {
 				filtered = append(filtered, r)
 			}
 		}
 
 		// Compute resources for removal
 		// The resource version can be set to "" here to trigger a removal even if never returned before
-		for name := range state.GetACKedResources() {
+		for name := range state.ReturnedResources() {
 			if _, ok := resources.resourceMap[name]; !ok {
 				toRemove = append(toRemove, name)
 			}
 		}
 	default:
-		nextVersionMap = make(map[string]string, len(state.GetSubscribedResources()))
+		nextVersionMap = make(map[string]string, len(state.SubscribedResources()))
 		// state.GetResourceVersions() may include resources no longer subscribed
 		// In the current code this gets silently cleaned when updating the version map
-		for name := range state.GetSubscribedResources() {
-			prevVersion, found := state.GetACKedResources()[name]
+		for name := range state.SubscribedResources() {
+			prevVersion, found := state.ReturnedResources()[name]
 			if r, ok := resources.resourceMap[name]; ok {
 				nextVersion := resources.versionMap[name]
 				if prevVersion != nextVersion {

pkg/cache/v3/delta_test.go

@@ -35,7 +35,7 @@ func TestSnapshotCacheDeltaWatch(t *testing.T) {
 	// Make our initial request as a wildcard to get all resources and make sure the wildcard requesting works as intended
 	for _, typ := range testTypes {
 		watches[typ] = make(chan cache.DeltaResponse, 1)
-		state := stream.NewSubscriptionState(true, nil)
+		state := stream.NewSubscription(true, nil)
 		_, err := c.CreateDeltaWatch(&discovery.DeltaDiscoveryRequest{
 			Node: &core.Node{
 				Id: "node",
@@ -69,9 +69,9 @@ func TestSnapshotCacheDeltaWatch(t *testing.T) {
 	// all resources as well as individual resource removals
 	for _, typ := range testTypes {
 		watches[typ] = make(chan cache.DeltaResponse, 1)
-		state := stream.NewSubscriptionState(false, versionMap[typ])
+		state := stream.NewSubscription(false, versionMap[typ])
 		for resource := range versionMap[typ] {
-			state.GetSubscribedResources()[resource] = struct{}{}
+			state.SubscribedResources()[resource] = struct{}{}
 		}
 		_, err := c.CreateDeltaWatch(&discovery.DeltaDiscoveryRequest{
 			Node: &core.Node{
@@ -113,21 +113,21 @@ func TestSnapshotCacheDeltaWatch(t *testing.T) {
 func TestDeltaRemoveResources(t *testing.T) {
 	c := cache.NewSnapshotCache(false, group{}, logger{t: t})
 	watches := make(map[string]chan cache.DeltaResponse)
-	streams := make(map[string]*stream.SubscriptionState)
+	subs := make(map[string]*stream.Subscription)
 
 	// At this stage the cache is empty, so a watch is opened
 	for _, typ := range testTypes {
 		watches[typ] = make(chan cache.DeltaResponse, 1)
-		state := stream.NewSubscriptionState(true, make(map[string]string))
-		streams[typ] = &state
+		state := stream.NewSubscription(true, make(map[string]string))
+		subs[typ] = &state
 		// We don't specify any resource name subscriptions here because we want to make sure we test wildcard
 		// functionality. This means we should receive all resources back without requesting a subscription by name.
 		_, err := c.CreateDeltaWatch(&discovery.DeltaDiscoveryRequest{
 			Node: &core.Node{
 				Id: "node",
 			},
 			TypeUrl: typ,
-		}, *streams[typ], watches[typ])
+		}, *subs[typ], watches[typ])
 		require.NoError(t, err)
 	}
 
@@ -144,7 +144,7 @@ func TestDeltaRemoveResources(t *testing.T) {
 			case out := <-watches[typ]:
 				assertResourceMapEqual(t, cache.IndexRawResourcesByName(out.(*cache.RawDeltaResponse).Resources), snapshot.GetResources(typ))
 				nextVersionMap := out.GetNextVersionMap()
-				streams[typ].SetACKedResources(nextVersionMap)
+				subs[typ].SetReturnedResources(nextVersionMap)
 			case <-time.After(time.Second):
 				require.Fail(t, "failed to receive a snapshot response")
 			}
@@ -161,7 +161,7 @@ func TestDeltaRemoveResources(t *testing.T) {
 			},
 			TypeUrl:       typ,
 			ResponseNonce: "nonce",
-		}, *streams[typ], watches[typ])
+		}, *subs[typ], watches[typ])
 		require.NoError(t, err)
 	}
 
@@ -181,7 +181,7 @@ func TestDeltaRemoveResources(t *testing.T) {
 		assert.Equal(t, []string{"otherCluster"}, out.(*cache.RawDeltaResponse).RemovedResources)
 		nextVersionMap := out.GetNextVersionMap()
 		// make sure the version maps are different since we no longer are tracking any endpoint resources
-		assert.NotEqual(t, nextVersionMap, streams[testTypes[0]].GetACKedResources(), "versionMap for the endpoint resource type did not change")
+		assert.NotEqual(t, nextVersionMap, subs[testTypes[0]].ReturnedResources(), "versionMap for the endpoint resource type did not change")
 	case <-time.After(time.Second):
 		assert.Fail(t, "failed to receive snapshot response")
 	}
@@ -206,7 +206,7 @@ func TestConcurrentSetDeltaWatch(t *testing.T) {
 						t.Fatalf("snapshot failed: %s", err)
 					}
 				} else {
-					state := stream.NewSubscriptionState(false, make(map[string]string))
+					state := stream.NewSubscription(false, make(map[string]string))
 					cancel, err := c.CreateDeltaWatch(&discovery.DeltaDiscoveryRequest{
 						Node: &core.Node{
 							Id: id,
@@ -230,7 +230,7 @@ func TestSnapshotDeltaCacheWatchTimeout(t *testing.T) {
 
 	// Create a non-buffered channel that will block sends.
 	watchCh := make(chan cache.DeltaResponse)
-	state := stream.NewSubscriptionState(false, nil)
+	state := stream.NewSubscription(false, nil)
 	state.SetSubscribedResources(map[string]struct{}{names[rsrc.EndpointType][0]: {}})
 	_, err := c.CreateDeltaWatch(&discovery.DeltaDiscoveryRequest{
 		Node: &core.Node{
@@ -275,7 +275,7 @@ func TestSnapshotCacheDeltaWatchCancel(t *testing.T) {
 	c := cache.NewSnapshotCache(true, group{}, logger{t: t})
 	for _, typ := range testTypes {
 		responses := make(chan cache.DeltaResponse, 1)
-		state := stream.NewSubscriptionState(false, make(map[string]string))
+		state := stream.NewSubscription(false, make(map[string]string))
 		cancel, err := c.CreateDeltaWatch(&discovery.DeltaDiscoveryRequest{
 			Node: &core.Node{
 				Id: key,

pkg/cache/v3/linear.go

@@ -106,6 +106,7 @@ func NewLinearCache(typeURL string, opts ...LinearCacheOption) *LinearCache {
 		versionMap:    nil,
 		version:       0,
 		versionVector: make(map[string]uint64),
+		log:           log.NewDefaultLogger(),
 	}
 	for _, opt := range opts {
 		opt(out)
@@ -164,31 +165,29 @@ func (cache *LinearCache) notifyAll(modified map[string]struct{}) {
 		}
 
 		for id, watch := range cache.deltaWatches {
-			if !watch.subscriptionState.WatchesResources(modified) {
+			if !watch.subscription.WatchesResources(modified) {
 				continue
 			}
 
-			res := cache.respondDelta(watch.Request, watch.Response, watch.subscriptionState)
+			res := cache.respondDelta(watch.Request, watch.Response, watch.subscription)
 			if res != nil {
 				delete(cache.deltaWatches, id)
 			}
 		}
 	}
 }
 
-func (cache *LinearCache) respondDelta(request *DeltaRequest, value chan DeltaResponse, clientState SubscriptionState) *RawDeltaResponse {
-	resp := createDeltaResponse(context.Background(), request, clientState, resourceContainer{
+func (cache *LinearCache) respondDelta(request *DeltaRequest, value chan DeltaResponse, sub Subscription) *RawDeltaResponse {
+	resp := createDeltaResponse(context.Background(), request, sub, resourceContainer{
 		resourceMap:   cache.resources,
 		versionMap:    cache.versionMap,
 		systemVersion: cache.getVersion(),
 	})
 
 	// Only send a response if there were changes
 	if len(resp.Resources) > 0 || len(resp.RemovedResources) > 0 {
-		if cache.log != nil {
-			cache.log.Debugf("[linear cache] node: %s, sending delta response for typeURL %s with resources: %v removed resources: %v with wildcard: %t",
-				request.GetNode().GetId(), request.GetTypeUrl(), GetResourceNames(resp.Resources), resp.RemovedResources, clientState.IsWildcard())
-		}
+		cache.log.Debugf("[linear cache] node: %s, sending delta response for typeURL %s with resources: %v removed resources: %v with wildcard: %t",
+			request.GetNode().GetId(), request.GetTypeUrl(), GetResourceNames(resp.Resources), resp.RemovedResources, sub.IsWildcard())
 		value <- resp
 		return resp
 	}
@@ -298,7 +297,7 @@ func (cache *LinearCache) GetResources() map[string]types.Resource {
 	return resources
 }
 
-func (cache *LinearCache) CreateWatch(request *Request, _ SubscriptionState, value chan Response) (func(), error) {
+func (cache *LinearCache) CreateWatch(request *Request, _ Subscription, value chan Response) (func(), error) {
 	if request.GetTypeUrl() != cache.typeURL {
 		value <- nil
 		return nil, fmt.Errorf("request type %s does not match cache type %s", request.TypeUrl, cache.typeURL)
@@ -372,7 +371,7 @@ func (cache *LinearCache) CreateWatch(request *Request, _ SubscriptionState, val
 	}, nil
 }
 
-func (cache *LinearCache) CreateDeltaWatch(request *DeltaRequest, clientState SubscriptionState, value chan DeltaResponse) (func(), error) {
+func (cache *LinearCache) CreateDeltaWatch(request *DeltaRequest, sub Subscription, value chan DeltaResponse) (func(), error) {
 	cache.mu.Lock()
 	defer cache.mu.Unlock()
 
@@ -385,22 +384,20 @@ func (cache *LinearCache) CreateDeltaWatch(request *DeltaRequest, clientState Su
 			modified[name] = struct{}{}
 		}
 		err := cache.updateVersionMap(modified)
-		if err != nil && cache.log != nil {
+		if err != nil {
 			cache.log.Errorf("failed to update version map: %v", err)
 		}
 	}
-	response := cache.respondDelta(request, value, clientState)
+	response := cache.respondDelta(request, value, sub)
 
 	// if respondDelta returns nil this means that there is no change in any resource version
 	// create a new watch accordingly
 	if response == nil {
 		watchID := cache.nextDeltaWatchID()
-		if cache.log != nil {
-			cache.log.Infof("[linear cache] open delta watch ID:%d for %s Resources:%v, system version %q", watchID,
-				cache.typeURL, clientState.GetSubscribedResources(), cache.getVersion())
-		}
+		cache.log.Infof("[linear cache] open delta watch ID:%d for %s Resources:%v, system version %q", watchID,
+			cache.typeURL, sub.SubscribedResources(), cache.getVersion())
 
-		cache.deltaWatches[watchID] = DeltaResponseWatch{Request: request, Response: value, subscriptionState: clientState}
+		cache.deltaWatches[watchID] = DeltaResponseWatch{Request: request, Response: value, subscription: sub}
 
 		return cache.cancelDeltaWatch(watchID), nil
 	}