feat: Improve plugin load error handling (#1214)

Loads plugins individually instead of failing to register if any plugin
fails to load. Previously if any plugin failed to load for any reason
then no plugins were registered.

Does some validation on if the manifest file exists and the structure of
it so that the errors are more descriptive. Does not throw a 2nd error
about `Unexpected token <` if there is no manifest file

packages/code-studio/src/main/AppInit.tsx

@@ -42,6 +42,7 @@ import {
   Workspace,
   WorkspaceStorage,
   ServerConfigValues,
+  DeephavenPluginModule,
 } from '@deephaven/redux';
 import { setLayoutStorage as setLayoutStorageAction } from '../redux/actions';
 import App from './App';
@@ -75,21 +76,30 @@ async function loadPlugins(): Promise<DeephavenPluginModuleMap> {
       `${import.meta.env.VITE_MODULE_PLUGINS_URL}/manifest.json`
     );
 
+    if (!Array.isArray(manifest.plugins)) {
+      throw new Error('Plugin manifest JSON does not contain plugins array');
+    }
+
     log.debug('Plugin manifest loaded:', manifest);
-    const pluginPromises = [];
+    const pluginPromises: Promise<unknown>[] = [];
     for (let i = 0; i < manifest.plugins.length; i += 1) {
       const { name, main } = manifest.plugins[i];
       const pluginMainUrl = `${
         import.meta.env.VITE_MODULE_PLUGINS_URL
       }/${name}/${main}`;
       pluginPromises.push(PluginUtils.loadModulePlugin(pluginMainUrl));
     }
-    const pluginModules = await Promise.all(pluginPromises);
+    const pluginModules = await Promise.allSettled(pluginPromises);
 
-    const pluginMap = new Map();
+    const pluginMap: DeephavenPluginModuleMap = new Map();
     for (let i = 0; i < pluginModules.length; i += 1) {
+      const module = pluginModules[i];
       const { name } = manifest.plugins[i];
-      pluginMap.set(name, pluginModules[i]);
+      if (module.status === 'fulfilled') {
+        pluginMap.set(name, module.value as DeephavenPluginModule);
+      } else {
+        log.error(`Unable to load plugin ${name}`, module.reason);
+      }
     }
     log.info('Plugins loaded:', pluginMap);
 

packages/code-studio/src/plugins/PluginUtils.tsx

@@ -58,22 +58,15 @@ class PluginUtils {
   static async loadJson(
     jsonUrl: string
   ): Promise<{ plugins: { name: string; main: string }[] }> {
-    return new Promise((resolve, reject) => {
-      const request = new XMLHttpRequest();
-      request.addEventListener('load', () => {
-        try {
-          const json = JSON.parse(request.responseText);
-          resolve(json);
-        } catch (err) {
-          reject(err);
-        }
-      });
-      request.addEventListener('error', err => {
-        reject(err);
-      });
-      request.open('GET', jsonUrl);
-      request.send();
-    });
+    const res = await fetch(jsonUrl);
+    if (!res.ok) {
+      throw new Error(res.statusText);
+    }
+    try {
+      return await res.json();
+    } catch {
+      throw new Error('Could not be parsed as JSON');
+    }
   }
 }