client/web: add visual indication for exit node pending approval (#10532)

Add visual indication when running as an exit node prior to receiving
admin approval.

Updates https://github.com/tailscale/tailscale/issues/10261

Signed-off-by: Mario Minardi <mario@tailscale.com>
Co-authored-by: Sonia Appasamy <sonia@tailscale.com>

client/web/src/api.ts

@@ -92,7 +92,8 @@ export function useAPI() {
     <MutateDataType, FetchDataType = any>(
       key: string,
       fetch: Promise<FetchDataType>,
-      optimisticData: (current: MutateDataType) => MutateDataType
+      optimisticData: (current: MutateDataType) => MutateDataType,
+      revalidate?: boolean // optionally specify whether to run final revalidation (step 3)
     ): Promise<FetchDataType | undefined> => {
       const options: MutatorOptions = {
         /**
@@ -105,6 +106,7 @@ export function useAPI() {
          */
         populateCache: false,
         optimisticData,
+        revalidate: revalidate,
       }
       return mutate(key, fetch, options)
     },
@@ -226,8 +228,12 @@ export function useAPI() {
                 ...old,
                 UsingExitNode: Boolean(body.UseExitNode) ? t.data : undefined,
                 AdvertisingExitNode: Boolean(body.AdvertiseExitNode),
+                AdvertisingExitNodeApproved: Boolean(body.AdvertiseExitNode)
+                  ? true // gets updated in revalidation
+                  : old.AdvertisingExitNodeApproved,
               }
-            }
+            },
+            false // skip final revalidation
           )
             .then(() => metrics.forEach((m) => incrementMetric(m)))
             .catch(handlePostError("Failed to update exit node"))

client/web/src/components/exit-node-selector.tsx

@@ -14,6 +14,7 @@ import useExitNodes, {
 import { ExitNode, NodeData } from "src/types"
 import Popover from "src/ui/popover"
 import SearchInput from "src/ui/search-input"
+import { useSWRConfig } from "swr"
 
 export default function ExitNodeSelector({
   className,
@@ -27,7 +28,14 @@ export default function ExitNodeSelector({
   const api = useAPI()
   const [open, setOpen] = useState<boolean>(false)
   const [selected, setSelected] = useState<ExitNode>(toSelectedExitNode(node))
+  const [pending, setPending] = useState<boolean>(false)
+  const { mutate } = useSWRConfig() // allows for global mutation
   useEffect(() => setSelected(toSelectedExitNode(node)), [node])
+  useEffect(() => {
+    setPending(
+      node.AdvertisingExitNode && node.AdvertisingExitNodeApproved === false
+    )
+  }, [node])
 
   const handleSelect = useCallback(
     (n: ExitNode) => {
@@ -35,9 +43,18 @@ export default function ExitNodeSelector({
       if (n.ID === selected.ID) {
         return // no update
       }
+      // Eager clear of pending state to avoid UI oddities
+      if (n.ID !== runAsExitNode.ID) {
+        setPending(false)
+      }
       api({ action: "update-exit-node", data: n })
+
+      // refresh data after short timeout to pick up any pending approval updates
+      setTimeout(() => {
+        mutate("/data")
+      }, 1000)
     },
-    [api, selected]
+    [api, mutate, selected.ID]
   )
 
   const [
@@ -52,7 +69,7 @@ export default function ExitNodeSelector({
       selected.ID !== noExitNode.ID && selected.ID !== runAsExitNode.ID,
       !selected.Online,
     ],
-    [selected]
+    [selected.ID, selected.Online]
   )
 
   return (
@@ -61,6 +78,7 @@ export default function ExitNodeSelector({
         "rounded-md",
         {
           "bg-red-600": offline,
+          "bg-yellow-400": pending,
         },
         className
       )}
@@ -160,6 +178,12 @@ export default function ExitNodeSelector({
           blocked until you disable the exit node or select a different one.
         </p>
       )}
+      {pending && (
+        <p className="text-white p-3">
+          Pending approval to run as exit node. This device won't be usable as
+          an exit node until then.
+        </p>
+      )}
     </div>
   )
 }

client/web/src/types.ts

@@ -15,6 +15,7 @@ export type NodeData = {
   KeyExpired: boolean
   UsingExitNode?: ExitNode
   AdvertisingExitNode: boolean
+  AdvertisingExitNodeApproved: boolean
   AdvertisedRoutes?: SubnetRoute[]
   TUNMode: boolean
   IsSynology: boolean

client/web/web.go

@@ -589,10 +589,11 @@ type nodeData struct {
 	UnraidToken string
 	URLPrefix   string // if set, the URL prefix the client is served behind
 
-	UsingExitNode       *exitNode
-	AdvertisingExitNode bool
-	AdvertisedRoutes    []subnetRoute // excludes exit node routes
-	RunningSSHServer    bool
+	UsingExitNode               *exitNode
+	AdvertisingExitNode         bool
+	AdvertisingExitNodeApproved bool          // whether running this node as an exit node has been approved by an admin
+	AdvertisedRoutes            []subnetRoute // excludes exit node routes
+	RunningSSHServer            bool
 
 	ClientVersion *tailcfg.ClientVersion
 
@@ -693,6 +694,8 @@ func (s *Server) serveGetNodeData(w http.ResponseWriter, r *http.Request) {
 			return p == route
 		})
 	}
+	data.AdvertisingExitNodeApproved = routeApproved(exitNodeRouteV4) || routeApproved(exitNodeRouteV6)
+
 	for _, r := range prefs.AdvertiseRoutes {
 		if r == exitNodeRouteV4 || r == exitNodeRouteV6 {
 			data.AdvertisingExitNode = true