feat: 🎸 Add fallback if client daemon is down or errors (#2085)

* feat: 🎸 Add fallback if client daemon is down or errors
* test: 💍 Add tests for client daemon being down

✅ Closes: https://hashicorp.atlassian.net/browse/ICU-12026

addons/api/addon/handlers/client-daemon-handler.js

@@ -39,6 +39,21 @@ const paginateResults = (array, page, pageSize) => {
   return array.slice(start, end);
 };
 
+const fetchControllerData = async (context, next) => {
+  const { data } = context.request;
+  const { query } = data;
+  const { recursive, scope_id, page, pageSize } = query;
+
+  // If we get an error or client daemon is unavailable, fall back to calling the API
+  context.request.data.query = { recursive, scope_id };
+  const results = await next(context.request);
+  const models = results.content.toArray();
+
+  const paginatedResult = paginateResults(models, page, pageSize);
+  paginatedResult.meta = { totalItems: models.length };
+  return paginatedResult;
+};
+
 /**
  * Handler to sit in front of the API request layer
  * so we can request from the daemon first
@@ -60,18 +75,17 @@ export default class ClientDaemonHandler {
           'isClientDaemonRunning',
         );
 
+        // eslint-disable-next-line no-unused-vars
+        let { recursive, scope_id, page, pageSize, ...remainingQuery } = query;
+        let searchQuery = '';
+
         if (
           !Object.keys(supportedTypes).includes(type) ||
           !isClientDaemonRunning
         ) {
-          return next(context.request);
+          return fetchControllerData(context, next);
         }
 
-        // TODO: Remove usages of recursive from callers and scope_id since
-        //  all calls to daemon are recursive, scope_id can be part of search query instead
-        // eslint-disable-next-line no-unused-vars
-        let { recursive, scope_id, page, pageSize, ...remainingQuery } = query;
-        let searchQuery = '';
         if (remainingQuery.query) {
           const { search, filters } = remainingQuery.query;
 
@@ -91,12 +105,20 @@ export default class ClientDaemonHandler {
           resource: pluralize(type),
         };
 
+        let clientDaemonResults = {};
+        try {
+          clientDaemonResults = await this.ipc.invoke(
+            'searchClientDaemon',
+            remainingQuery,
+          );
+        } catch (e) {
+          return fetchControllerData(context, next);
+        }
+
         // Currently returns with a singular top level field with resource name
         // e.g. { targets: [...] } or { sessions: [..] }
         // So this just unwraps to the array, or undefined
-        const [results] = Object.values(
-          await this.ipc.invoke('searchClientDaemon', remainingQuery),
-        );
+        const [results] = Object.values(clientDaemonResults);
         const payload = { items: paginateResults(results, page, pageSize) };
 
         const schema = store.modelFor(type);