feat(api): answer the front door instead of 404ing it

apps/api/src/app.test.ts

@@ -50,6 +50,28 @@ async function post(app: Hono<AppEnv>, path: string, body: unknown = {}): Promis
   });
 }
 
+describe('root', () => {
+  test('the front door says what is running rather than 404ing', async () => {
+    const { app } = await harness('root-index');
+    const response = await app.request('/');
+
+    // The bug this replaces: pasting the hostname into a browser returned
+    // {"error":{"code":"not_found"}}, which reads as a broken deployment.
+    expect(response.status).toBe(200);
+    expect(await response.json()).toMatchObject({
+      service: 'api',
+      endpoints: { health: '/health/live', api: '/api/v1' },
+    });
+  });
+
+  test('an unknown path is still a 404', async () => {
+    const { app } = await harness('root-unknown');
+    const response = await app.request('/nope');
+
+    expect(response.status).toBe(404);
+  });
+});
+
 describe('health', () => {
   test('liveness does not depend on the database', async () => {
     const { app } = await harness('health-live');

apps/api/src/app.ts

@@ -41,6 +41,25 @@ export function createApp(options: AppOptions): Hono<AppEnv> {
 
   app.use('*', cors());
 
+  // ------------------------------------------------------------------ root
+  // An API with no route at `/` answers the front door with a 404, which reads
+  // as "the deployment is broken" to anybody who pastes the hostname into a
+  // browser — including us. This says what is running and where to go instead.
+  app.get('/', (c) =>
+    c.json({
+      service: 'api',
+      name: 'outreachgraph',
+      version: options.version ?? '0.1.0',
+      ...(options.commitHash ? { commitHash: options.commitHash } : {}),
+      docs: 'https://github.com/profullstack/outreachgraph',
+      endpoints: {
+        health: '/health/live',
+        ready: '/health/ready',
+        api: '/api/v1',
+      },
+    }),
+  );
+
   // ---------------------------------------------------------------- health
   // Two endpoints: liveness never touches the database so a database blip
   // cannot cause Railway to kill a healthy process; readiness does.