replace cache.GetNodes with NodeWatcher in lib/web

lib/services/watcher.go

@@ -1177,6 +1177,12 @@ func (n *nodeCollector) GetNodes(fn func(n Node) bool) []types.Server {
 	return matched
 }
 
+func (n *nodeCollector) NodeCount() int {
+	n.rw.RLock()
+	defer n.rw.RUnlock()
+	return len(n.current)
+}
+
 // resourceKind specifies the resource kind to watch.
 func (n *nodeCollector) resourceKind() string {
 	return types.KindNode

lib/srv/regular/proxy.go

@@ -453,9 +453,9 @@ func (t *proxySubsys) proxyToHost(
 	return nil
 }
 
-// NodeGetter is a function that retrieves a subset of nodes matching
+// NodesGetter is a function that retrieves a subset of nodes matching
 // the filter criteria.
-type NodeGetter interface {
+type NodesGetter interface {
 	GetNodes(fn func(n services.Node) bool) []types.Server
 }
 
@@ -464,7 +464,7 @@ type NodeGetter interface {
 // is types.RoutingStrategy_UNAMBIGUOUS_MATCH. When the strategy is types.RoutingStrategy_MOST_RECENT then
 // the server that has heartbeated most recently will be returned instead of an error. If no matches are found then
 // both the types.Server and error returned will be nil.
-func (t *proxySubsys) getMatchingServer(watcher NodeGetter, strategy types.RoutingStrategy) (types.Server, error) {
+func (t *proxySubsys) getMatchingServer(watcher NodesGetter, strategy types.RoutingStrategy) (types.Server, error) {
 	if watcher == nil {
 		return nil, trace.NotFound("unable to retrieve nodes matching host %s", t.host)
 	}

lib/web/apiserver.go

@@ -1934,12 +1934,12 @@ func (h *Handler) siteNodeConnect(
 	req.ProxyHostPort = h.ProxyHostPort()
 	req.Cluster = site.GetName()
 
-	clt, err := ctx.GetUserClient(site)
+	watcher, err := site.NodeWatcher()
 	if err != nil {
 		return nil, trace.Wrap(err)
 	}
 
-	term, err := NewTerminal(r.Context(), *req, clt, ctx)
+	term, err := NewTerminal(*req, watcher, ctx)
 	if err != nil {
 		h.log.WithError(err).Error("Unable to create terminal.")
 		return nil, trace.Wrap(err)
@@ -1963,24 +1963,19 @@ type siteSessionGenerateResponse struct {
 // siteSessionCreate generates a new site session that can be used by UI
 // The ServerID from request can be in the form of hostname, uuid, or ip address.
 func (h *Handler) siteSessionGenerate(w http.ResponseWriter, r *http.Request, p httprouter.Params, ctx *SessionContext, site reversetunnel.RemoteSite) (interface{}, error) {
-	clt, err := ctx.GetUserClient(site)
-	if err != nil {
-		return nil, trace.Wrap(err)
-	}
-
 	var req *siteSessionGenerateReq
 	if err := httplib.ReadJSON(r, &req); err != nil {
 		return nil, trace.Wrap(err)
 	}
 
 	namespace := apidefaults.Namespace
 	if req.Session.ServerID != "" {
-		servers, err := clt.GetNodes(r.Context(), namespace)
+		watcher, err := site.NodeWatcher()
 		if err != nil {
 			return nil, trace.Wrap(err)
 		}
 
-		hostname, _, err := resolveServerHostPort(req.Session.ServerID, servers)
+		hostname, _, err := resolveServerHostPort(req.Session.ServerID, watcher)
 		if err != nil {
 			return nil, trace.Wrap(err)
 		}