Added health metrics for application load and database load (#2257)

* Added health metrics for application load

* Added health metrics for application load

* Fix unit tests

* Added more metrics

* Added few comments

* Added DatabaseLoad Scenario and address comments

* Fix unit tests

* fix unit tests

* Fix unit tests

* fix unit tests

* fix the mock

* Fix unit tests

src/Metrics/MetricEvents.test.ts

@@ -0,0 +1,104 @@
+import { configContext, Platform } from "../ConfigContext";
+import { getAuthorizationHeader } from "../Utils/AuthorizationUtils";
+import { fetchWithTimeout } from "../Utils/FetchWithTimeout";
+import MetricScenario, { reportHealthy, reportUnhealthy } from "./MetricEvents";
+
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { Response } = require("node-fetch");
+
+jest.mock("../Utils/AuthorizationUtils", () => ({
+  getAuthorizationHeader: jest.fn().mockReturnValue({ header: "authorization", token: "Bearer test-token" }),
+}));
+
+jest.mock("../Utils/FetchWithTimeout", () => ({
+  fetchWithTimeout: jest.fn(),
+}));
+
+describe("MetricEvents", () => {
+  const mockFetchWithTimeout = fetchWithTimeout as jest.MockedFunction<typeof fetchWithTimeout>;
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  test("reportHealthy success includes auth header", async () => {
+    const mockResponse = new Response(null, { status: 200 });
+    mockFetchWithTimeout.mockResolvedValue(mockResponse);
+
+    const result = await reportHealthy(MetricScenario.ApplicationLoad, Platform.Portal, "SQL");
+
+    expect(result).toBeInstanceOf(Response);
+    expect(result.ok).toBe(true);
+    expect(result.status).toBe(200);
+    expect(mockFetchWithTimeout).toHaveBeenCalledTimes(1);
+
+    const callArgs = mockFetchWithTimeout.mock.calls[0];
+    expect(callArgs[0]).toContain("/api/dataexplorer/metrics/health");
+    expect(callArgs[1]?.headers).toEqual({
+      "Content-Type": "application/json",
+      authorization: "Bearer test-token",
+    });
+
+    const body = JSON.parse(callArgs[1]?.body as string);
+    expect(body.scenario).toBe(MetricScenario.ApplicationLoad);
+    expect(body.platform).toBe(Platform.Portal);
+    expect(body.api).toBe("SQL");
+    expect(body.healthy).toBe(true);
+    expect(getAuthorizationHeader).toHaveBeenCalled();
+  });
+
+  test("reportUnhealthy failure status", async () => {
+    const mockResponse = new Response("Failure", { status: 500 });
+    mockFetchWithTimeout.mockResolvedValue(mockResponse);
+
+    const result = await reportUnhealthy(MetricScenario.ApplicationLoad, Platform.Portal, "SQL");
+
+    expect(result).toBeInstanceOf(Response);
+    expect(result.ok).toBe(false);
+    expect(result.status).toBe(500);
+
+    const callArgs = mockFetchWithTimeout.mock.calls[0];
+    const body = JSON.parse(callArgs[1]?.body as string);
+    expect(body.healthy).toBe(false);
+  });
+
+  test("helpers healthy/unhealthy", async () => {
+    mockFetchWithTimeout.mockResolvedValue(new Response(null, { status: 201 }));
+
+    const healthyResult = await reportHealthy(MetricScenario.ApplicationLoad, Platform.Portal, "SQL");
+    const unhealthyResult = await reportUnhealthy(MetricScenario.ApplicationLoad, Platform.Portal, "SQL");
+
+    expect(healthyResult.status).toBe(201);
+    expect(unhealthyResult.status).toBe(201);
+    expect(mockFetchWithTimeout).toHaveBeenCalledTimes(2);
+  });
+
+  test("throws when backend endpoint missing", async () => {
+    const original = configContext.PORTAL_BACKEND_ENDPOINT;
+    (configContext as { PORTAL_BACKEND_ENDPOINT: string }).PORTAL_BACKEND_ENDPOINT = "";
+
+    await expect(reportHealthy(MetricScenario.ApplicationLoad, Platform.Portal, "SQL")).rejects.toThrow(
+      "baseUri is null or empty",
+    );
+
+    expect(mockFetchWithTimeout).not.toHaveBeenCalled();
+    (configContext as { PORTAL_BACKEND_ENDPOINT: string }).PORTAL_BACKEND_ENDPOINT = original;
+  });
+
+  test("propagates fetch errors", async () => {
+    mockFetchWithTimeout.mockRejectedValue(new Error("Network error"));
+
+    await expect(reportHealthy(MetricScenario.ApplicationLoad, Platform.Portal, "SQL")).rejects.toThrow(
+      "Network error",
+    );
+  });
+
+  test("propagates timeout errors", async () => {
+    const abortError = new DOMException("The operation was aborted", "AbortError");
+    mockFetchWithTimeout.mockRejectedValue(abortError);
+
+    await expect(reportUnhealthy(MetricScenario.ApplicationLoad, Platform.Portal, "SQL")).rejects.toThrow(
+      "The operation was aborted",
+    );
+  });
+});