Add option to persist missing tags in regional cache

.changeset/loud-mice-know.md

@@ -0,0 +1,5 @@
+---
+"@opennextjs/cloudflare": patch
+---
+
+Add an option to persist missing tags in the regional tag cache

examples/e2e/app-router/open-next.config.ts

@@ -10,6 +10,8 @@ export default defineCloudflareConfig({
 	// With such a configuration, we could have up to 12 * (8 + 2) = 120 Durable Objects instances
 	tagCache: shardedTagCache({
 		baseShardSize: 12,
+		regionalCache: true,
+		regionalCacheDangerouslyPersistMissingTags: true,
 		shardReplication: {
 			numberOfSoftReplicas: 8,
 			numberOfHardReplicas: 2,

packages/cloudflare/src/api/overrides/tag-cache/do-sharded-tag-cache.spec.ts

@@ -5,9 +5,12 @@ import shardedDOTagCache, { AVAILABLE_REGIONS, DOId } from "./do-sharded-tag-cac
 const hasBeenRevalidatedMock = vi.fn();
 const writeTagsMock = vi.fn();
 const idFromNameMock = vi.fn();
-const getMock = vi
-	.fn()
-	.mockReturnValue({ hasBeenRevalidated: hasBeenRevalidatedMock, writeTags: writeTagsMock });
+const getRevalidationTimesMock = vi.fn();
+const getMock = vi.fn().mockReturnValue({
+	hasBeenRevalidated: hasBeenRevalidatedMock,
+	writeTags: writeTagsMock,
+	getRevalidationTimes: getRevalidationTimesMock,
+});
 const waitUntilMock = vi.fn().mockImplementation(async (fn) => fn());
 globalThis.continent = undefined;
 const sendDLQMock = vi.fn();
@@ -391,6 +394,165 @@ describe("DOShardedTagCache", () => {
 		});
 	});
 
+	describe("putToRegionalCache", () => {
+		it("should return early if regional cache is disabled", async () => {
+			const cache = shardedDOTagCache();
+			const doId = new DOId({
+				baseShardId: "shard-1",
+				numberOfReplicas: 1,
+				shardType: "hard",
+			});
+			await cache.putToRegionalCache({ doId, tags: ["tag1"] }, getMock());
+			expect(getRevalidationTimesMock).not.toHaveBeenCalled();
+		});
+
+		it("should put the tags in the regional cache if the tags exists in the DO", async () => {
+			const putMock = vi.fn();
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = {
+				open: vi.fn().mockResolvedValue({
+					put: putMock,
+				}),
+			};
+			const cache = shardedDOTagCache({ baseShardSize: 4, regionalCache: true });
+			const doId = new DOId({
+				baseShardId: "shard-1",
+				numberOfReplicas: 1,
+				shardType: "hard",
+			});
+
+			getRevalidationTimesMock.mockResolvedValueOnce({ tag1: 123456 });
+
+			await cache.putToRegionalCache({ doId, tags: ["tag1"] }, getMock());
+
+			expect(getRevalidationTimesMock).toHaveBeenCalledWith(["tag1"]);
+			expect(putMock).toHaveBeenCalledWith(
+				"http://local.cache/shard/tag-hard;shard-1?tag=tag1",
+				expect.any(Response)
+			);
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = undefined;
+		});
+
+		it("should not put the tags in the regional cache if the tags does not exists in the DO", async () => {
+			const putMock = vi.fn();
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = {
+				open: vi.fn().mockResolvedValue({
+					put: putMock,
+				}),
+			};
+			const cache = shardedDOTagCache({ baseShardSize: 4, regionalCache: true });
+			const doId = new DOId({
+				baseShardId: "shard-1",
+				numberOfReplicas: 1,
+				shardType: "hard",
+			});
+
+			getRevalidationTimesMock.mockResolvedValueOnce({});
+
+			await cache.putToRegionalCache({ doId, tags: ["tag1"] }, getMock());
+
+			expect(getRevalidationTimesMock).toHaveBeenCalledWith(["tag1"]);
+			expect(putMock).not.toHaveBeenCalled();
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = undefined;
+		});
+
+		it("should put multiple tags in the regional cache", async () => {
+			const putMock = vi.fn();
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = {
+				open: vi.fn().mockResolvedValue({
+					put: putMock,
+				}),
+			};
+			const cache = shardedDOTagCache({ baseShardSize: 4, regionalCache: true });
+			const doId = new DOId({
+				baseShardId: "shard-1",
+				numberOfReplicas: 1,
+				shardType: "hard",
+			});
+
+			getRevalidationTimesMock.mockResolvedValueOnce({ tag1: 123456, tag2: 654321 });
+
+			await cache.putToRegionalCache({ doId, tags: ["tag1", "tag2"] }, getMock());
+
+			expect(getRevalidationTimesMock).toHaveBeenCalledWith(["tag1", "tag2"]);
+			expect(putMock).toHaveBeenCalledWith(
+				"http://local.cache/shard/tag-hard;shard-1?tag=tag1",
+				expect.any(Response)
+			);
+			expect(putMock).toHaveBeenCalledWith(
+				"http://local.cache/shard/tag-hard;shard-1?tag=tag2",
+				expect.any(Response)
+			);
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = undefined;
+		});
+
+		it("should put missing tag in the regional cache if `regionalCacheDangerouslyPersistMissingTags` is true", async () => {
+			const putMock = vi.fn();
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = {
+				open: vi.fn().mockResolvedValue({
+					put: putMock,
+				}),
+			};
+			const cache = shardedDOTagCache({
+				baseShardSize: 4,
+				regionalCache: true,
+				regionalCacheDangerouslyPersistMissingTags: true,
+			});
+			const doId = new DOId({
+				baseShardId: "shard-1",
+				numberOfReplicas: 1,
+				shardType: "hard",
+			});
+
+			getRevalidationTimesMock.mockResolvedValueOnce({});
+
+			await cache.putToRegionalCache({ doId, tags: ["tag1"] }, getMock());
+
+			expect(getRevalidationTimesMock).toHaveBeenCalledWith(["tag1"]);
+			expect(putMock).toHaveBeenCalledWith(
+				"http://local.cache/shard/tag-hard;shard-1?tag=tag1",
+				expect.any(Response)
+			);
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = undefined;
+		});
+
+		it("should not put missing tag in the regional cache if `regionalCacheDangerouslyPersistMissingTags` is false", async () => {
+			const putMock = vi.fn();
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = {
+				open: vi.fn().mockResolvedValue({
+					put: putMock,
+				}),
+			};
+			const cache = shardedDOTagCache({
+				baseShardSize: 4,
+				regionalCache: true,
+				regionalCacheDangerouslyPersistMissingTags: false,
+			});
+			const doId = new DOId({
+				baseShardId: "shard-1",
+				numberOfReplicas: 1,
+				shardType: "hard",
+			});
+
+			getRevalidationTimesMock.mockResolvedValueOnce({});
+
+			await cache.putToRegionalCache({ doId, tags: ["tag1"] }, getMock());
+
+			expect(getRevalidationTimesMock).toHaveBeenCalledWith(["tag1"]);
+			expect(putMock).not.toHaveBeenCalled();
+			// @ts-expect-error - Defined on cloudfare context
+			globalThis.caches = undefined;
+		});
+	});
+
 	describe("getCacheKey", () => {
 		it("should return the cache key without the random part", async () => {
 			const cache = shardedDOTagCache();

packages/cloudflare/src/api/overrides/tag-cache/do-sharded-tag-cache.ts

@@ -49,6 +49,14 @@ interface ShardedDOTagCacheOptions {
 	 */
 	regionalCacheTtlSec?: number;
 
+	/**
+	 * Whether to persist missing tags in the regional cache.
+	 * This is dangerous if you don't invalidate the Cache API when you revalidate tags as you could end up storing stale data in the data cache.
+	 *
+	 * @default false
+	 */
+	regionalCacheDangerouslyPersistMissingTags?: boolean;
+
 	/**
 	 * Enable shard replication to handle higher load.
 	 *
@@ -465,8 +473,15 @@ class ShardedDOTagCache implements NextModeTagCache {
 		const tagsLastRevalidated = await stub.getRevalidationTimes(tags);
 		await Promise.all(
 			tags.map(async (tag) => {
-				const lastRevalidated = tagsLastRevalidated[tag];
-				if (lastRevalidated === undefined) return; // Should we store something in the cache if the tag is not found ?
+				let lastRevalidated = tagsLastRevalidated[tag];
+				if (lastRevalidated === undefined) {
+					if (this.opts.regionalCacheDangerouslyPersistMissingTags) {
+						lastRevalidated = 0; // If the tag is not found, we set it to 0 as it means it has never been revalidated before.
+					} else {
+						debugCache("Tag not found in revalidation times", { tag, optsKey });
+						return; // If the tag is not found, we skip it
+					}
+				}
 				const cacheKey = this.getCacheUrlKey(optsKey.doId, tag);
 				debugCache("Putting to regional cache", { cacheKey, lastRevalidated });
 				await cache.put(