webapi: Abort requests if web cache not ready.

internal/webapi/admin.go

@@ -144,8 +144,10 @@ func (w *WebAPI) statusJSON(c *gin.Context) {
 
 // adminPage is the handler for "GET /admin".
 func (w *WebAPI) adminPage(c *gin.Context) {
+	cacheData := c.MustGet(cacheKey).(cacheData)
+
 	c.HTML(http.StatusOK, "admin.html", gin.H{
-		"WebApiCache":  w.cache.getData(),
+		"WebApiCache":  cacheData,
 		"WebApiCfg":    w.cfg,
 		"WalletStatus": w.walletStatus(c),
 		"DcrdStatus":   w.dcrdStatus(c),
@@ -155,6 +157,8 @@ func (w *WebAPI) adminPage(c *gin.Context) {
 // ticketSearch is the handler for "POST /admin/ticket". The hash param will be
 // used to retrieve a ticket from the database.
 func (w *WebAPI) ticketSearch(c *gin.Context) {
+	cacheData := c.MustGet(cacheKey).(cacheData)
+
 	hash := c.PostForm("hash")
 
 	ticket, found, err := w.db.GetTicketByHash(hash)
@@ -218,7 +222,7 @@ func (w *WebAPI) ticketSearch(c *gin.Context) {
 			VoteChanges:     voteChanges,
 			MaxVoteChanges:  w.cfg.MaxVoteChangeRecords,
 		},
-		"WebApiCache":  w.cache.getData(),
+		"WebApiCache":  cacheData,
 		"WebApiCfg":    w.cfg,
 		"WalletStatus": w.walletStatus(c),
 		"DcrdStatus":   w.dcrdStatus(c),
@@ -228,12 +232,14 @@ func (w *WebAPI) ticketSearch(c *gin.Context) {
 // adminLogin is the handler for "POST /admin". If a valid password is provided,
 // the current session will be authenticated as an admin.
 func (w *WebAPI) adminLogin(c *gin.Context) {
+	cacheData := c.MustGet(cacheKey).(cacheData)
+
 	password := c.PostForm("password")
 
 	if password != w.cfg.AdminPass {
 		w.log.Warnf("Failed login attempt from %s", c.ClientIP())
 		c.HTML(http.StatusUnauthorized, "login.html", gin.H{
-			"WebApiCache":    w.cache.getData(),
+			"WebApiCache":    cacheData,
 			"WebApiCfg":      w.cfg,
 			"FailedLoginMsg": "Incorrect password",
 		})

internal/webapi/cache.go

@@ -30,6 +30,10 @@ type cache struct {
 }
 
 type cacheData struct {
+	// Initialized is set true after all of the below values have been set for
+	// the first time.
+	Initialized bool
+
 	UpdateTime          string
 	PubKey              string
 	DatabaseSize        string
@@ -45,6 +49,13 @@ type cacheData struct {
 	MissedProportion    float32
 }
 
+func (c *cache) initialized() bool {
+	c.mtx.RLock()
+	defer c.mtx.RUnlock()
+
+	return c.data.Initialized
+}
+
 func (c *cache) getData() cacheData {
 	c.mtx.RLock()
 	defer c.mtx.RUnlock()
@@ -106,6 +117,7 @@ func (c *cache) update() error {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 
+	c.data.Initialized = true
 	c.data.UpdateTime = dateTime(time.Now().Unix())
 	c.data.DatabaseSize = humanize.Bytes(dbSize)
 	c.data.Voting = voting

internal/webapi/homepage.go

@@ -11,8 +11,10 @@ import (
 )
 
 func (w *WebAPI) homepage(c *gin.Context) {
+	cacheData := c.MustGet(cacheKey).(cacheData)
+
 	c.HTML(http.StatusOK, "homepage.html", gin.H{
-		"WebApiCache": w.cache.getData(),
+		"WebApiCache": cacheData,
 		"WebApiCfg":   w.cfg,
 	})
 }

internal/webapi/middleware.go

@@ -93,15 +93,31 @@ func (w *WebAPI) withSession(store *sessions.CookieStore) gin.HandlerFunc {
 	}
 }
 
+// requireWebCache will only allow the request to proceed if the web API cache
+// has been initialized with data, otherwise it will return a 500 Internal
+// Server Error.
+func (w *WebAPI) requireWebCache(c *gin.Context) {
+	if !w.cache.initialized() {
+		const str = "Cache is not yet initialized"
+		w.log.Errorf(str)
+		c.String(http.StatusInternalServerError, str)
+		c.Abort()
+		return
+	}
+
+	c.Set(cacheKey, w.cache.getData())
+}
+
 // requireAdmin will only allow the request to proceed if the current session is
 // authenticated as an admin, otherwise it will render the login template.
 func (w *WebAPI) requireAdmin(c *gin.Context) {
+	cacheData := c.MustGet(cacheKey).(cacheData)
 	session := c.MustGet(sessionKey).(*sessions.Session)
 	admin := session.Values["admin"]
 
 	if admin == nil {
 		c.HTML(http.StatusUnauthorized, "login.html", gin.H{
-			"WebApiCache": w.cache.getData(),
+			"WebApiCache": cacheData,
 			"WebApiCfg":   w.cfg,
 		})
 		c.Abort()

internal/webapi/vspinfo.go

@@ -14,7 +14,8 @@ import (
 
 // vspInfo is the handler for "GET /api/v3/vspinfo".
 func (w *WebAPI) vspInfo(c *gin.Context) {
-	cachedStats := w.cache.getData()
+	cachedStats := c.MustGet(cacheKey).(cacheData)
+
 	w.sendJSONResponse(types.VspInfoResponse{
 		APIVersions:         []int64{3},
 		Timestamp:           time.Now().Unix(),

internal/webapi/webapi.go

@@ -57,6 +57,7 @@ const (
 	dcrdKey              = "DcrdClient"
 	dcrdHostKey          = "DcrdHostname"
 	dcrdErrorKey         = "DcrdClientErr"
+	cacheKey             = "Cache"
 	walletsKey           = "WalletClients"
 	failedWalletsKey     = "FailedWalletClients"
 	requestBytesKey      = "RequestBytes"
@@ -240,7 +241,7 @@ func (w *WebAPI) router(cookieSecret []byte, dcrd rpc.DcrdConnect, wallets rpc.W
 	// API routes.
 
 	api := router.Group("/api/v3")
-	api.GET("/vspinfo", w.vspInfo)
+	api.GET("/vspinfo", w.requireWebCache, w.vspInfo)
 	api.POST("/setaltsignaddr", w.vspMustBeOpen, w.withDcrdClient(dcrd), w.broadcastTicket, w.vspAuth, w.setAltSignAddr)
 	api.POST("/feeaddress", w.vspMustBeOpen, w.withDcrdClient(dcrd), w.broadcastTicket, w.vspAuth, w.feeAddress)
 	api.POST("/ticketstatus", w.withDcrdClient(dcrd), w.vspAuth, w.ticketStatus)
@@ -249,26 +250,31 @@ func (w *WebAPI) router(cookieSecret []byte, dcrd rpc.DcrdConnect, wallets rpc.W
 
 	// Website routes.
 
-	router.GET("", w.homepage)
+	router.GET("", w.requireWebCache, w.homepage)
 
 	login := router.Group("/admin").Use(
 		w.withSession(cookieStore),
 	)
 
 	// Limit login attempts to 3 per second.
 	loginRateLmiter := rateLimit(3, func(c *gin.Context) {
+		cacheData := c.MustGet(cacheKey).(cacheData)
+
 		w.log.Warnf("Login rate limit exceeded by %s", c.ClientIP())
 		c.HTML(http.StatusTooManyRequests, "login.html", gin.H{
-			"WebApiCache":    w.cache.getData(),
+			"WebApiCache":    cacheData,
 			"WebApiCfg":      w.cfg,
 			"FailedLoginMsg": "Rate limit exceeded",
 		})
 	})
-	login.POST("", loginRateLmiter, w.adminLogin)
+	login.POST("", w.requireWebCache, loginRateLmiter, w.adminLogin)
 
 	admin := router.Group("/admin").Use(
-		w.withWalletClients(wallets), w.withSession(cookieStore), w.requireAdmin,
-	)
+		w.requireWebCache,
+		w.withWalletClients(wallets),
+		w.withSession(cookieStore),
+		w.requireAdmin)
+
 	admin.GET("", w.withDcrdClient(dcrd), w.adminPage)
 	admin.POST("/ticket", w.withDcrdClient(dcrd), w.ticketSearch)
 	admin.GET("/backup", w.downloadDatabaseBackup)