feat(devops): separate public page server timing diagnostics

src/lib/public-page-performance.test.ts

@@ -0,0 +1,76 @@
+import { beforeEach, expect, it, vi } from "vitest";
+import { measureDependency } from "./performance-diagnostics";
+
+const mocks = vi.hoisted(() => ({ record: vi.fn() }));
+vi.mock("./performance-store", () => ({ recordPerformance: mocks.record }));
+
+import { withPublicPagePerformance } from "./public-page-performance";
+
+beforeEach(() => {
+	mocks.record.mockClear();
+});
+it("measures concurrent pages with static labels and never stores props", async () => {
+	const render = withPublicPagePerformance(
+		"/u/[username]",
+		async (props: { username: string }) => {
+			await measureDependency("database", async () => 1);
+			return props.username;
+		},
+	);
+	expect(
+		await Promise.all([
+			render({ username: "PrivateName" }),
+			render({ username: "AnotherName" }),
+		]),
+	).toEqual(["PrivateName", "AnotherName"]);
+	const records = mocks.record.mock.calls.map(([record]) => record);
+	expect(records).toHaveLength(2);
+	expect(records[0].metrics.database.count).toBe(1);
+	expect(records[0].operationId).not.toBe(records[1].operationId);
+	expect(JSON.stringify(records)).not.toMatch(/PrivateName|AnotherName/);
+	expect(records[0]).toMatchObject({
+		kind: "public-page",
+		route: "/u/[username]",
+		outcome: "completed",
+	});
+});
+it("preserves framework redirects and labels them separately from failures", async () => {
+	const error = Object.assign(new Error("private redirect"), {
+		digest: "NEXT_REDIRECT;replace;/login;307;",
+	});
+	const render = withPublicPagePerformance("/me", async () => {
+		throw error;
+	});
+	await expect(render(undefined)).rejects.toBe(error);
+	expect(mocks.record).toHaveBeenCalledWith(
+		expect.objectContaining({ outcome: "redirect" }),
+	);
+	expect(JSON.stringify(mocks.record.mock.calls)).not.toContain("/login");
+});
+it("keeps missing pages distinct and records dependency failures", async () => {
+	const error = Object.assign(new Error("private"), {
+		digest: "NEXT_HTTP_ERROR_FALLBACK;404",
+	});
+	await expect(
+		withPublicPagePerformance("/news/[slug]", async () => {
+			throw error;
+		})(undefined),
+	).rejects.toBe(error);
+	expect(mocks.record).toHaveBeenCalledWith(
+		expect.objectContaining({ outcome: "not-found" }),
+	);
+});
+it("excludes static build invocations without changing their result", async () => {
+	vi.stubEnv("NEXT_PHASE", "phase-production-build");
+	try {
+		expect(
+			await withPublicPagePerformance(
+				"/news",
+				async () => "content",
+			)(undefined),
+		).toBe("content");
+		expect(mocks.record).not.toHaveBeenCalled();
+	} finally {
+		vi.unstubAllEnvs();
+	}
+});