Refactor update check.

- Switch away from GitHub releases API to a statically hosted custom
  JSON message to include richer data.
- Instead of checking 24 hours post-boot, check 15 mins later post boot
  and then every 24 hours.
- Add provision for messages to display on the admin dashboard to
  communicate important / urgent announcements.
  (Fingers crossed, this never has to be used!)

cmd/updates.go

@@ -10,18 +10,25 @@ import (
 	"golang.org/x/mod/semver"
 )
 
-const updateCheckURL = "https://api.github.com/repos/knadh/listmonk/releases/latest"
+const updateCheckURL = "https://update.listmonk.app/update.json"
 
-type remoteUpdateResp struct {
-	Version string `json:"tag_name"`
-	URL     string `json:"html_url"`
-}
-
-// AppUpdate contains information of a new update available to the app that
-// is sent to the frontend.
 type AppUpdate struct {
-	Version string `json:"version"`
-	URL     string `json:"url"`
+	Update struct {
+		ReleaseVersion string `json:"release_version"`
+		ReleaseDate    string `json:"release_date"`
+		URL            string `json:"url"`
+		Description    string `json:"description"`
+
+		// This is computed and set locally based on the local version.
+		IsNew bool `json:"is_new"`
+	} `json:"update"`
+	Messages []struct {
+		Date        string `json:"date"`
+		Title       string `json:"title"`
+		Description string `json:"description"`
+		URL         string `json:"url"`
+		Priority    string `json:"priority"`
+	} `json:"messages"`
 }
 
 var reSemver = regexp.MustCompile(`-(.*)`)
@@ -32,11 +39,12 @@ var reSemver = regexp.MustCompile(`-(.*)`)
 func checkUpdates(curVersion string, interval time.Duration, app *App) {
 	// Strip -* suffix.
 	curVersion = reSemver.ReplaceAllString(curVersion, "")
-	time.Sleep(time.Second * 1)
-	ticker := time.NewTicker(interval)
-	defer ticker.Stop()
 
-	for range ticker.C {
+	// Give a 15 minute buffer after app start in case the admin wants to disable
+	// update checks entirely and not make a request to upstream.
+	time.Sleep(time.Minute * 1)
+
+	for {
 		resp, err := http.Get(updateCheckURL)
 		if err != nil {
 			app.log.Printf("error checking for remote update: %v", err)
@@ -55,25 +63,25 @@ func checkUpdates(curVersion string, interval time.Duration, app *App) {
 		}
 		resp.Body.Close()
 
-		var up remoteUpdateResp
-		if err := json.Unmarshal(b, &up); err != nil {
+		var out AppUpdate
+		if err := json.Unmarshal(b, &out); err != nil {
 			app.log.Printf("error unmarshalling remote update payload: %v", err)
 			continue
 		}
 
 		// There is an update. Set it on the global app state.
-		if semver.IsValid(up.Version) {
-			v := reSemver.ReplaceAllString(up.Version, "")
+		if semver.IsValid(out.Update.ReleaseVersion) {
+			v := reSemver.ReplaceAllString(out.Update.ReleaseVersion, "")
 			if semver.Compare(v, curVersion) > 0 {
-				app.Lock()
-				app.update = &AppUpdate{
-					Version: up.Version,
-					URL:     up.URL,
-				}
-				app.Unlock()
-
-				app.log.Printf("new update %s found", up.Version)
+				out.Update.IsNew = true
+				app.log.Printf("new update %s found", out.Update.ReleaseVersion)
 			}
 		}
+
+		app.Lock()
+		app.update = &out
+		app.Unlock()
+
+		time.Sleep(interval)
 	}
 }

frontend/.eslintrc.js

@@ -21,6 +21,7 @@ module.exports = {
     'vue/max-attributes-per-line': 'off',
     'vue/html-indent': 'off',
     'vue/html-closing-bracket-newline': 'off',
+    'vue/singleline-html-element-content-newline': 'off',
     'vue/max-len': ['error', {
       code: 200,
       template: 200,

frontend/src/App.vue

@@ -58,10 +58,24 @@
               {{ $t('settings.restart') }}
             </b-button>
           </div>
-          <div v-if="serverConfig.update" class="notification is-success">
-            {{ $t('settings.updateAvailable', { version: serverConfig.update.version }) }}
-            <a :href="serverConfig.update.url" target="_blank" rel="noopener noreferer">View</a>
+
+          <div v-if="serverConfig.update.update.is_new" class="notification is-success">
+            {{ $t('settings.updateAvailable', {
+              version: `${serverConfig.update.update.release_version}
+            (${$utils.getDate(serverConfig.update.update.release_date).format('DD MMM YY')})`,
+            }) }}
+            <a :href="serverConfig.update.update.url" target="_blank" rel="noopener noreferer">View</a>
           </div>
+
+          <template v-if="serverConfig.update.messages && serverConfig.update.messages.length > 0">
+            <div v-for="m in serverConfig.update.messages" class="notification"
+              :class="{ [m.priority === 'high' ? 'is-danger' : 'is-info']: true }" :key="m.title">
+              <h3 class="is-size-5" v-if="m.title"><strong>{{ m.title }}</strong></h3>
+              <p v-if="m.description">{{ m.description }}</p>
+              <a v-if="m.url" :href="m.url" target="_blank" rel="noopener noreferer">View</a>
+            </div>
+          </template>
+
           <div v-if="serverConfig.has_legacy_user" class="notification is-danger">
             <b-icon icon="warning-empty" />
             Remove the <code>admin_username</code> and <code>admin_password</code> fields from the TOML

frontend/src/assets/style.scss

@@ -252,7 +252,7 @@ body.is-noscroll {
 }
 .notification {
   padding: 10px 15px;
-  border-left: 5px solid #eee;
+  border-left: 10px solid #eee;
 
   &.is-danger {
     background: $white-ter;
@@ -264,6 +264,11 @@ body.is-noscroll {
     color: $black;
     border-left-color: $green;
   }
+  &.is-info {
+    background: $white-ter;
+    border-left-color: $primary;
+    color: $grey-dark;
+  }
 }
 
 /* WYSIWYG / HTML code editor */