fix: negative-cache property/Connect JSON fetch failures

src/js/16-bloblang-interactive.js

@@ -72,6 +72,42 @@
     );
   }
 
+  /**
+   * Track Connect JSON URLs that recently returned an error response, so a
+   * URL that is known to 404 (for example, a version whose JSON was never
+   * generated) is not re-requested on every page view.
+   */
+  const FETCH_FAILURE_KEY = 'connect-json-fetch-failures';
+  const FETCH_FAILURE_TTL = 60 * 60 * 1000; // 1 hour
+
+  function readFetchFailures() {
+    try {
+      const parsed = JSON.parse(localStorage.getItem(FETCH_FAILURE_KEY) || '{}');
+      const now = Date.now();
+      const fresh = {};
+      Object.keys(parsed).forEach((url) => {
+        if (now - parsed[url] < FETCH_FAILURE_TTL) fresh[url] = parsed[url];
+      });
+      return fresh;
+    } catch (e) {
+      return {};
+    }
+  }
+
+  function hasRecentFetchFailure(url) {
+    return url in readFetchFailures();
+  }
+
+  function markFetchFailure(url) {
+    try {
+      const failures = readFetchFailures();
+      failures[url] = Date.now();
+      localStorage.setItem(FETCH_FAILURE_KEY, JSON.stringify(failures));
+    } catch (e) {
+      // localStorage not available
+    }
+  }
+
   /**
    * Parse a Bloblang snippet into mapping, input, and metadata sections.
    * Looks for # In: and # Meta: comment directives.
@@ -196,11 +232,18 @@
         if (!url) {
           url = `/redpanda-connect/components/_attachments/connect-${version}.json`;
         }
+
+        if (hasRecentFetchFailure(url)) {
+          return null;
+        }
       }
 
       const response = await fetch(url);
 
       if (!response.ok) {
+        if (!isPreviewMode()) {
+          markFetchFailure(url);
+        }
         return null;
       }
 

src/js/19-property-tooltips.js

@@ -92,6 +92,7 @@
 
     var CACHE_KEY = 'redpanda-properties-cache'
     var CACHE_TTL = 24 * 60 * 60 * 1000 // 24 hours
+    var FAILURE_CACHE_TTL = 60 * 60 * 1000 // 1 hour: retry failed fetches sooner so a fix deploy is picked up
     // Use latest-redpanda-tag meta tag for cache versioning
     var cacheVersion = getLatestRedpandaTag() || 'unknown'
 
@@ -101,8 +102,11 @@
         var cached = localStorage.getItem(CACHE_KEY)
         if (cached) {
           var parsed = JSON.parse(cached)
-          if (parsed.version === cacheVersion && Date.now() - parsed.timestamp < CACHE_TTL) {
-            propertiesData = parsed.data
+          var age = Date.now() - parsed.timestamp
+          if (parsed.version === cacheVersion && (parsed.failed ? age < FAILURE_CACHE_TTL : age < CACHE_TTL)) {
+            // failed entries resolve to an empty lookup so a URL known to 404
+            // is not re-requested on every page view
+            propertiesData = parsed.failed ? {} : parsed.data
             propertiesLoading = false
             propertiesLoadQueue.forEach(function (resolve) {
               resolve(propertiesData)
@@ -182,6 +186,20 @@
         }
 
         console.warn('Property tooltips: Failed to load properties data:', error)
+        if (!isPreviewMode()) {
+          try {
+            localStorage.setItem(
+              CACHE_KEY,
+              JSON.stringify({
+                version: cacheVersion,
+                timestamp: Date.now(),
+                failed: true,
+              })
+            )
+          } catch (cacheError) {
+            // localStorage full or unavailable
+          }
+        }
         propertiesLoading = false
         propertiesData = {}
         propertiesLoadQueue.forEach(function (resolve) {