Remove now-unused asset preservation cache v1 from Pages (#7544)

Author: GregBrimble

.changeset/green-socks-trade.md

@@ -0,0 +1,5 @@
+---
+"@cloudflare/pages-shared": patch
+---
+
+chore: Remove now-unused asset preservation cache (v1)

packages/pages-shared/__tests__/asset-server/handler.test.ts

@@ -611,90 +611,6 @@ describe("asset-server handler", () => {
 				}
 			`);
 		});
-
-		test("preservationCacheV1 (fallback)", async () => {
-			vi.setSystemTime(new Date("2024-05-09")); // 1 day before fallback is disabled
-
-			const deploymentId = "deployment-" + Math.random();
-			const metadata = createMetadataObject({ deploymentId }) as Metadata;
-			const { caches } = createCacheStorage();
-
-			const preservationCacheV1 = await caches.open("assetPreservationCache");
-
-			// Write a response to the V1 cache and make sure it persists
-			await preservationCacheV1.put(
-				"https://example.com/foo",
-				new Response("preserved in V1 cache!", {
-					headers: {
-						"Cache-Control": "public, max-age=300",
-					},
-				})
-			);
-
-			const preservationRes = await preservationCacheV1.match(
-				"https://example.com/foo"
-			);
-
-			if (!preservationRes) {
-				throw new Error(
-					"Did not match preservation cache on https://example.com/foo"
-				);
-			}
-
-			expect(await preservationRes.text()).toMatchInlineSnapshot(
-				`"preserved in V1 cache!"`
-			);
-
-			// Delete the asset from the manifest and ensure it's served from V1 preservation cache
-			const findAssetEntryForPath = async (_path: string) => {
-				return null;
-			};
-			const { response, spies } = await getTestResponse({
-				request: new Request("https://example.com/foo"),
-				metadata,
-				findAssetEntryForPath,
-				caches,
-				fetchAsset: () =>
-					Promise.resolve(Object.assign(new Response("hello world!"))),
-			});
-			expect(response.status).toBe(200);
-			expect(await response.text()).toMatchInlineSnapshot(
-				`"preserved in V1 cache!"`
-			);
-			expect(Object.fromEntries(response.headers)).toMatchInlineSnapshot(`
-				{
-				  "access-control-allow-origin": "*",
-				  "cache-control": "public, max-age=300",
-				  "cf-cache-status": "HIT",
-				  "content-type": "text/plain;charset=UTF-8",
-				  "referrer-policy": "strict-origin-when-cross-origin",
-				  "x-content-type-options": "nosniff",
-				}
-			`);
-			// No cache or early hints writes
-			expect(spies.waitUntil.length).toBe(0);
-
-			// Should disable fallback starting may 10th
-			vi.setSystemTime(new Date("2024-05-10"));
-			const { response: response2, spies: spies2 } = await getTestResponse({
-				request: new Request("https://example.com/foo"),
-				metadata,
-				findAssetEntryForPath,
-				caches,
-				fetchAsset: () =>
-					Promise.resolve(Object.assign(new Response("hello world!"))),
-			});
-			expect(response2.status).toBe(404);
-			expect(Object.fromEntries(response2.headers)).toMatchInlineSnapshot(`
-				{
-				  "access-control-allow-origin": "*",
-				  "cache-control": "no-store",
-				  "referrer-policy": "strict-origin-when-cross-origin",
-				}
-			`);
-			// No cache or early hints writes
-			expect(spies2.waitUntil.length).toBe(0);
-		});
 	});
 
 	describe("isPreservationCacheResponseExpiring()", async () => {

packages/pages-shared/asset-server/handler.ts

@@ -25,10 +25,8 @@ type BodyEncoding = "manual" | "automatic";
 // Before serving a 404, we check the cache to see if we've served this asset recently
 // and if so, serve it from the cache instead of responding with a 404.
 // This gives a bit of a grace period between deployments for any clients browsing the old deployment.
-export const ASSET_PRESERVATION_CACHE_V1 = "assetPreservationCache";
-// V2 stores the content hash instead of the asset.
-// TODO: Remove V1 once we've fully migrated to V2
-export const ASSET_PRESERVATION_CACHE_V2 = "assetPreservationCacheV2";
+// Only the content hash is actually stored in the body.
+export const ASSET_PRESERVATION_CACHE = "assetPreservationCacheV2";
 const CACHE_CONTROL_PRESERVATION = "public, s-maxage=604800"; // 1 week
 
 /** The preservation cache should be periodically
@@ -576,14 +574,14 @@ export async function generateHandler<
 				waitUntil(
 					(async () => {
 						try {
-							const assetPreservationCacheV2 = await caches.open(
-								ASSET_PRESERVATION_CACHE_V2
+							const assetPreservationCache = await caches.open(
+								ASSET_PRESERVATION_CACHE
 							);
 
 							// Check if the asset has changed since last written to cache
 							// or if the cached entry is getting too old and should have
 							// it's expiration reset.
-							const match = await assetPreservationCacheV2.match(request);
+							const match = await assetPreservationCache.match(request);
 							if (
 								!match ||
 								assetKey !== (await match.text()) ||
@@ -599,7 +597,7 @@ export async function generateHandler<
 								);
 								preservedResponse.headers.set("x-robots-tag", "noindex");
 
-								await assetPreservationCacheV2.put(
+								await assetPreservationCache.put(
 									request.url,
 									preservedResponse
 								);
@@ -637,30 +635,13 @@ export async function generateHandler<
 	async function notFound(): Promise<Response> {
 		if (caches) {
 			try {
-				const assetPreservationCacheV2 = await caches.open(
-					ASSET_PRESERVATION_CACHE_V2
+				const assetPreservationCache = await caches.open(
+					ASSET_PRESERVATION_CACHE
 				);
-				let preservedResponse = await assetPreservationCacheV2.match(
+				const preservedResponse = await assetPreservationCache.match(
 					request.url
 				);
 
-				// Continue serving from V1 preservation cache for some time to
-				// prevent 404s during the migration to V2
-				const cutoffDate = new Date("2024-05-17");
-				if (!preservedResponse && Date.now() < cutoffDate.getTime()) {
-					const assetPreservationCacheV1 = await caches.open(
-						ASSET_PRESERVATION_CACHE_V1
-					);
-					preservedResponse = await assetPreservationCacheV1.match(request.url);
-					if (preservedResponse) {
-						// V1 cache contains full response bodies so we return it directly
-						if (setMetrics) {
-							setMetrics({ preservationCacheResult: "checked-hit" });
-						}
-						return preservedResponse;
-					}
-				}
-
 				// V2 cache only contains the asset key, rather than the asset body:
 				if (preservedResponse) {
 					if (setMetrics) {
@@ -674,6 +655,7 @@ export async function generateHandler<
 					}
 					if (assetKey) {
 						const asset = await fetchAsset(assetKey);
+
 						if (asset) {
 							// We know the asset hasn't changed, so use the cached headers.
 							return new Response(asset.body, preservedResponse);