Add /health to aggregator

aggregator/src/app/AppEvent.ts

@@ -88,4 +88,5 @@ type AppEvent =
     };
   };
 
+
 export default AppEvent;

aggregator/src/app/BundleRouter.ts

@@ -2,7 +2,6 @@ import { Router } from "../../deps.ts";
 import failRequest from "./helpers/failRequest.ts";
 import BundleHandler from "./helpers/BundleHandler.ts";
 import nil from "../helpers/nil.ts";
-
 import BundleService from "./BundleService.ts";
 
 export default function BundleRouter(bundleService: BundleService) {

aggregator/src/app/HealthRouter.ts

@@ -0,0 +1,16 @@
+import { Router } from "../../deps.ts";
+import HealthService from "./HealthService.ts";
+
+export default function HealthRouter(healthService: HealthService) {
+  const router = new Router({ prefix: "/" });
+
+  router.get(
+    "health", 
+    async (ctx) => {
+      const healthResults = await healthService.getHealth();
+      console.log(`Status: ${healthResults.status}\n`);
+      ctx.response.status = healthResults.status == 'healthy' ? 200 : 503;
+      ctx.response.body = { status: healthResults.status };
+  });
+  return router;
+}

aggregator/src/app/HealthService.ts

@@ -0,0 +1,11 @@
+export type ResourceHealth = 'healthy' | 'unhealthy';
+
+type HealthCheckResult = {
+  status: ResourceHealth,
+};
+
+export default class HealthService {
+  getHealth(): Promise<HealthCheckResult> {
+    return Promise.resolve({ status: 'healthy' });
+  }
+}

aggregator/src/app/app.ts

@@ -15,6 +15,8 @@ import AppEvent from "./AppEvent.ts";
 import BundleTable from "./BundleTable.ts";
 import AggregationStrategy from "./AggregationStrategy.ts";
 import AggregationStrategyRouter from "./AggregationStrategyRouter.ts";
+import HealthService from "./HealthService.ts";
+import HealthRouter from "./HealthRouter.ts";
 
 export default async function app(emit: (evt: AppEvent) => void) {
   const { addresses } = await getNetworkConfig();
@@ -64,10 +66,13 @@ export default async function app(emit: (evt: AppEvent) => void) {
     bundleTable,
   );
 
+  const healthService = new HealthService();
+
   const routers = [
     BundleRouter(bundleService),
     AdminRouter(adminService),
     AggregationStrategyRouter(aggregationStrategy),
+    HealthRouter(healthService),
   ];
 
   const app = new Application();

aggregator/test/HealthService.test.ts

@@ -0,0 +1,10 @@
+import { assertEquals } from "./deps.ts";
+
+import Fixture from "./helpers/Fixture.ts";
+
+Fixture.test("HealthService returns healthy", async (fx) => {
+  const healthCheckService = fx.createHealthCheckService()
+  const healthStatus = await healthCheckService.getHealth();
+  const expected = {"status":"healthy"};
+  assertEquals(JSON.stringify(healthStatus), JSON.stringify(expected));
+});

aggregator/test/helpers/Fixture.ts

@@ -25,6 +25,7 @@ import BundleTable, { BundleRow } from "../../src/app/BundleTable.ts";
 import AggregationStrategy, {
   AggregationStrategyConfig,
 } from "../../src/app/AggregationStrategy.ts";
+import HealthService from "../../src/app/HealthService.ts";
 
 // deno-lint-ignore no-explicit-any
 type ExplicitAny = any;
@@ -292,6 +293,12 @@ export default class Fixture {
 
     return wallets;
   }
+  
+  createHealthCheckService() {
+    const healthCheckService = new HealthService();
+    
+    return healthCheckService;
+  }
 
   async cleanup() {
     for (const job of this.cleanupJobs) {