fix(dev): stop the dev server watching .gev-cache and .gev-logs (#761)

Providers write cache files and logs into .gev-cache and .gev-logs while the app runs. A serve-only standalone plugin adds both to server.watch.ignored, so the dev watcher no longer stats them; source changes still reload.

changelog.d/761-dev-unwatched-runtime-dirs.md

@@ -0,0 +1,5 @@
+- The dev server no longer watches `.gev-cache` and `.gev-logs`. Providers write
+  cache files and logs there while the app runs, and none of it is source, so
+  the watcher now skips it; this guards against the DNS-lookup delays heavy
+  cache writes have caused, though no difference was measured on current main
+  (monwiss, #761).

server/standalone/unwatched-cache.js

@@ -0,0 +1,28 @@
+/**
+ * Directories the app writes to while it runs. None is source, and none
+ * should reload anything.
+ */
+const RUNTIME_WRITE_GLOBS = Object.freeze([
+  '**/.gev-cache/**',
+  '**/.gev-logs/**',
+]);
+
+/**
+ * Keep the directories the app writes to out of the dev server's file watcher.
+ *
+ * Disk-cached providers write a file per response into `.gev-cache`, and the
+ * voice debug log appends to `.gev-logs`. Left watched, each write costs the
+ * watcher stat calls on libuv's thread pool, which `getaddrinfo` shares; heavy
+ * cache writes have been seen to delay upstream DNS lookups.
+ *
+ * @returns {import('vite').Plugin} Config-only plugin; no server hooks.
+ */
+export function unwatchedRuntimeDirsPlugin() {
+  return {
+    name: 'gev-unwatched-runtime-dirs',
+    apply: 'serve',
+    config: () => ({
+      server: { watch: { ignored: [...RUNTIME_WRITE_GLOBS] } },
+    }),
+  };
+}

server/standalone/vite.config.js

@@ -6,6 +6,7 @@ import { localProviderPlugins } from '../providers/local.js';
 import { localMcpPlugin } from '../mcp/plugin.js';
 import { apiNotFoundPlugin } from './api-not-found.js';
 import { standaloneVoiceTools } from './voiceTools.js';
+import { unwatchedRuntimeDirsPlugin } from './unwatched-cache.js';
 
 const root = fileURLToPath(new URL('../../', import.meta.url));
 
@@ -20,6 +21,7 @@ export default defineConfig(({ command, mode }) => {
       ...localProviderPlugins({ realtime: { tools: standaloneVoiceTools() } }),
       localMcpPlugin(),
       apiNotFoundPlugin(),
+      unwatchedRuntimeDirsPlugin(),
     ],
     googleApiKey: process.env.GOOGLE_MAPS_API_KEY,
     cesiumToken: process.env.CESIUM_ION_TOKEN,

src/tooling/viteBuild.test.mjs

@@ -89,17 +89,34 @@ test('root config retains existing named exports and standalone provider order',
     assert.equal(compatibility[name], value, name);
   const config = standaloneConfig({ mode: 'test' });
   assert.deepEqual(
-    config.plugins.slice(3, -4).map((plugin) => plugin.name),
+    config.plugins.slice(3, -5).map((plugin) => plugin.name),
     providers.localProviderPlugins().map((plugin) => plugin.name),
   );
-  assert.equal(config.plugins.at(-5).name, 'gev-key-setup');
+  assert.equal(config.plugins.at(-6).name, 'gev-key-setup');
   // The local MCP route follows every provider and precedes the API fallback.
-  assert.equal(config.plugins.at(-4).name, 'local-mcp');
-  assert.equal(config.plugins.at(-3).name, 'api-not-found');
+  assert.equal(config.plugins.at(-5).name, 'local-mcp');
+  assert.equal(config.plugins.at(-4).name, 'api-not-found');
+  // Config-only, so it sits after the provider slice rather than in it.
+  assert.equal(config.plugins.at(-3).name, 'gev-unwatched-runtime-dirs');
   assert.equal(config.plugins.at(-2).name, 'embed-framing');
   assert.equal(config.plugins.at(-1).name, 'panel-build');
 });
 
+test('directories the server writes while it runs are kept out of the dev watcher', () => {
+  // Providers write cache files and logs here while the app runs; none of it is
+  // source, so the dev watcher has no reason to stat it.
+  const config = standaloneConfig({ mode: 'test' });
+  const plugin = config.plugins.find(
+    ({ name }) => name === 'gev-unwatched-runtime-dirs',
+  );
+  // Dev only: preview and build have no watcher.
+  assert.equal(plugin.apply, 'serve');
+  assert.deepEqual(plugin.config().server.watch.ignored, [
+    '**/.gev-cache/**',
+    '**/.gev-logs/**',
+  ]);
+});
+
 test('build export resolves in Node and has no browser fallback', async () => {
   const exported = await import('gods-eye-view/build/vite');
   assert.equal(exported.createBrowserViteConfig, createBrowserViteConfig);