feat: rate limit error chaching (#2448)

* feat: rate limit error chaching

Rate limit error caching to alleviate PATs.

* refactor: improve code comments

tests/api.test.js

@@ -184,13 +184,18 @@ describe("Test /api/", () => {
     ]);
   });
 
-  it("should not store cache when error", async () => {
+  it("should set shorter cache when error", async () => {
     const { req, res } = faker({}, error);
     await api(req, res);
 
     expect(res.setHeader.mock.calls).toEqual([
       ["Content-Type", "image/svg+xml"],
-      ["Cache-Control", `no-cache, no-store, must-revalidate`],
+      [
+        "Cache-Control",
+        `max-age=${CONSTANTS.ERROR_CACHE_SECONDS / 2}, s-maxage=${
+          CONSTANTS.ERROR_CACHE_SECONDS
+        }, stale-while-revalidate=${CONSTANTS.ONE_DAY}`,
+      ],
     ]);
   });
 

tests/retryer.test.js

@@ -1,6 +1,6 @@
 import { jest } from "@jest/globals";
 import "@testing-library/jest-dom";
-import { retryer } from "../src/common/retryer.js";
+import { retryer, RETRIES } from "../src/common/retryer.js";
 import { logger } from "../src/common/utils.js";
 import { expect, it, describe } from "@jest/globals";
 
@@ -44,7 +44,7 @@ describe("Test Retryer", () => {
     try {
       await retryer(fetcherFail, {});
     } catch (err) {
-      expect(fetcherFail).toBeCalledTimes(8);
+      expect(fetcherFail).toBeCalledTimes(RETRIES + 1);
       expect(err.message).toBe("Downtime due to GitHub API rate limiting");
     }
   });