upstash · fahreddinozcan · Jul 30, 2024 · Jul 8, 2024 · Jul 9, 2024 · Jul 9, 2024
diff --git a/pkg/commands/command.ts b/pkg/commands/command.ts
@@ -83,7 +83,9 @@ export class Command<TResult, TData> {
   public async exec(client: Requester): Promise<TData> {
     const { result, error } = await client.request<TResult>({
       body: this.command,
+      upstashSyncToken: client.upstashSyncToken,
     });
+
     if (error) {
       throw new UpstashError(error);
     }

diff --git a/pkg/http.ts b/pkg/http.ts
@@ -15,10 +15,21 @@ export type UpstashRequest = {
    * Request body will be serialized to json
    */
   body?: unknown;
+
+  upstashSyncToken?: string;
 };
 export type UpstashResponse<TResult> = { result?: TResult; error?: string };
 
-export type Requester = {
+export interface Requester {
+  /**
+   * When this flag is enabled, any subsequent commands issued by this client are guaranteed to observe the effects of all earlier writes submitted by the same client.
+   */
+  readYourWrites?: boolean;
+
+  /**
+   * This token is used to ensure that the client is in sync with the server. On each request, we send this token in the header, and the server will return a new token.
+   */
+  upstashSyncToken?: string;
   request: <TResult = unknown>(req: UpstashRequest) => Promise<UpstashResponse<TResult>>;
 };
 
@@ -95,11 +106,17 @@ export type HttpClientConfig = {
   agent?: any;
   signal?: AbortSignal;
   keepAlive?: boolean;
+
+  /**
+   * When this flag is enabled, any subsequent commands issued by this client are guaranteed to observe the effects of all earlier writes submitted by the same client.
+   */
+  readYourWrites?: boolean;
 } & RequesterConfig;
 
 export class HttpClient implements Requester {
   public baseUrl: string;
   public headers: Record<string, string>;
+
   public readonly options: {
     backend?: string;
     agent: any;
@@ -108,6 +125,8 @@ export class HttpClient implements Requester {
     cache?: CacheSetting;
     keepAlive: boolean;
   };
+  public readYourWrites: boolean;
+  public upstashSyncToken = "";
 
   public readonly retry: {
     attempts: number;
@@ -123,6 +142,8 @@ export class HttpClient implements Requester {
       signal: config.signal,
       keepAlive: config.keepAlive ?? true,
     };
+    this.upstashSyncToken = "";
+    this.readYourWrites = config.readYourWrites ?? true;
 
     this.baseUrl = config.baseUrl.replace(/\/$/, "");
 
@@ -185,6 +206,14 @@ export class HttpClient implements Requester {
       backend: this.options.backend,
     };
 
+    /**
+     * We've recieved a new `upstash-sync-token` in the previous response. We use it in the next request to observe the effects of previous requests.
+     */
+    if (this.readYourWrites) {
+      const newHeader = this.upstashSyncToken;
+      this.headers["upstash-sync-token"] = newHeader;
+    }
+
     let res: Response | null = null;
     let error: Error | null = null;
     for (let i = 0; i <= this.retry.attempts; i++) {
@@ -216,6 +245,20 @@ export class HttpClient implements Requester {
       throw new UpstashError(`${body.error}, command was: ${JSON.stringify(req.body)}`);
     }
 
+    if (this.readYourWrites) {
+      const headers = res.headers;
+      this.upstashSyncToken = headers.get("upstash-sync-token") ?? "";
+    }
+
+
+     /**
+     * We save the new `upstash-sync-token` in the response header to use it in the next request.
+     */
+    if (this.readYourWrites) {
+      const headers = res.headers;
+      this.upstashSyncToken = headers.get("upstash-sync-token") ?? "";
+    }
+
     if (this.options.responseEncoding === "base64") {
       if (Array.isArray(body)) {
         return body.map(({ result, error }) => ({
@@ -226,6 +269,7 @@ export class HttpClient implements Requester {
       const result = decode(body.result) as any;
       return { result, error: body.error };
     }
+
     return body as UpstashResponse<TResult>;
   }
 }

diff --git a/pkg/pipeline.ts b/pkg/pipeline.ts
@@ -283,6 +283,7 @@ export class Pipeline<TCommands extends Command<any, any>[] = []> {
       throw new Error("Pipeline is empty");
     }
     const path = this.multiExec ? ["multi-exec"] : ["pipeline"];
+
     const res = (await this.client.request({
       path,
       body: Object.values(this.commands).map((c) => c.command),

diff --git a/pkg/read-your-writes.test.ts b/pkg/read-your-writes.test.ts
@@ -0,0 +1,115 @@
+import { keygen, newHttpClient } from "./test-utils";
+
+import { afterAll, describe, expect, test } from "bun:test";
+
+import { Redis as PublicRedis } from "../platforms/nodejs";
+import { SetCommand } from "./commands/set";
+import { Redis } from "./redis";
+
+const client = newHttpClient();
+const { cleanup } = keygen();
+afterAll(cleanup);
+describe("Read Your Writes Feature", () => {
+  test("successfully retrieves Upstash-Sync-Token in the response header and updates local state", async () => {
+    const initialSync = client.upstashSyncToken;
+    await new SetCommand(["key", "value"]).exec(client);
+    const updatedSync = client.upstashSyncToken;
+    await new SetCommand(["key", "value"]).exec(client);
+
+    expect(updatedSync).not.toEqual(initialSync);
+  });
+
+  test("succesfully updates sync state with pipeline", async () => {
+    const initialSync = client.upstashSyncToken;
+
+    const { pipeline } = new Redis(client);
+    const p = pipeline();
+
+    p.set("key1", "value1");
+    p.set("key2", "value2");
+    p.set("key3", "value3");
+
+    await p.exec();
+
+    const updatedSync = client.upstashSyncToken;
+
+    expect(initialSync).not.toEqual(updatedSync);
+  });
+
+  test("updates after each element of promise.all", async () => {
+    let currentSync = client.upstashSyncToken;
+
+    const promises = Array.from({ length: 3 }, (_, i) =>
+      new SetCommand([`key${i}`, `value${i}`]).exec(client).then(() => {
+        expect(client.upstashSyncToken).not.toEqual(currentSync);
+        currentSync = client.upstashSyncToken;
+      }),
+    );
+
+    await Promise.all(promises);
+  });
+
+  test("updates after successful lua script call", async () => {
+    const s = `redis.call('SET', 'mykey', 'myvalue')
+		return 1
+		`;
+
+    const initialSync = client.upstashSyncToken;
+
+    const redis = new Redis(client);
+    const script = redis.createScript(s);
+
+    await script.exec([], []);
+
+    const updatedSync = client.upstashSyncToken;
+
+    expect(updatedSync).not.toEqual(initialSync);
+  });
+
+  test("should not update the sync state in case of Redis client with manuel HTTP client and opt-out ryw", async () => {
+    const optOutClient = newHttpClient();
+    const redis = new Redis(optOutClient, { readYourWrites: false });
+
+    const initialSync = optOutClient.upstashSyncToken;
+
+    await redis.set("key", "value");
+
+    const updatedSync = optOutClient.upstashSyncToken;
+
+    expect(updatedSync).toEqual(initialSync);
+  });
+
+  test("should not update the sync state when public Redis interface is provided with opt-out", async () => {
+    const redis = new PublicRedis({
+      url: process.env.UPSTASH_REDIS_REST_URL,
+      token: process.env.UPSTASH_REDIS_REST_TOKEN,
+      readYourWrites: false,
+    });
+
+    // @ts-expect-error - We need the sync token for this test, which resides on the client
+    const initialSync = redis.client.upstashSyncToken;
+
+    await redis.set("key", "value");
+
+    // @ts-expect-error - We need the sync token for this test, which resides on the client
+    const updatedSync = redis.client.upstashSyncToken;
+
+    expect(updatedSync).toEqual(initialSync);
+  });
+
+  test("should update the sync state when public Redis interface is provided with default behaviour", async () => {
+    const redis = new PublicRedis({
+      url: process.env.UPSTASH_REDIS_REST_URL,
+      token: process.env.UPSTASH_REDIS_REST_TOKEN,
+    });
+
+    // @ts-expect-error - We need the sync token for this test, which resides on the client
+    const initialSync = redis.client.upstashSyncToken;
+
+    await redis.set("key", "value");
+
+    // @ts-expect-error - We need the sync token for this test, which resides on the client
+    const updatedSync = redis.client.upstashSyncToken;
+    expect(updatedSync).not.toEqual(initialSync);
+  });
+});
diff --git a/pkg/redis.ts b/pkg/redis.ts
@@ -210,6 +210,10 @@ export class Redis {
     this.client = client;
     this.opts = opts;
     this.enableTelemetry = opts?.enableTelemetry ?? true;
+
+    if (opts?.readYourWrites === false) {
+      this.client.readYourWrites = false;
+    }
     this.enableAutoPipelining = opts?.enableAutoPipelining ?? true;
   }
 

diff --git a/pkg/types.ts b/pkg/types.ts
@@ -31,4 +31,5 @@ export type RedisOptions = {
   latencyLogging?: boolean;
   enableTelemetry?: boolean;
   enableAutoPipelining?: boolean;
+  readYourWrites?: boolean;
 };
diff --git a/platforms/cloudflare.ts b/platforms/cloudflare.ts
@@ -30,6 +30,11 @@ export type RedisConfigCloudflare = {
    */
   signal?: AbortSignal;
   keepAlive?: boolean;
+
+  /**
+  * When this flag is enabled, any subsequent commands issued by this client are guaranteed to observe the effects of all earlier writes submitted by the same client.
+  */
+  readYourWrites?: boolean;
 } & core.RedisOptions &
   RequesterConfig &
   Env;
@@ -51,15 +56,11 @@ export class Redis extends core.Redis {
    */
   constructor(config: RedisConfigCloudflare, env?: Env) {
     if (!config.url) {
-      throw new Error(
-        `[Upstash Redis] The 'url' property is missing or undefined in your Redis config.`
-      );
+      throw new Error(`[Upstash Redis] The 'url' property is missing or undefined in your Redis config.`)
     }
 
     if (!config.token) {
-      throw new Error(
-        `[Upstash Redis] The 'token' property is missing or undefined in your Redis config.`
-      );
+      throw new Error(`[Upstash Redis] The 'token' property is missing or undefined in your Redis config.`)
     }
 
     if (config.url.startsWith(" ") || config.url.endsWith(" ") || /\r|\n/.test(config.url)) {
@@ -76,6 +77,7 @@ export class Redis extends core.Redis {
       responseEncoding: config.responseEncoding,
       signal: config.signal,
       keepAlive: config.keepAlive,
+      readYourWrites: config.readYourWrites,
     });
 
     super(client, {

diff --git a/platforms/fastly.ts b/platforms/fastly.ts
@@ -27,6 +27,11 @@ export type RedisConfigFastly = {
    */
   backend: string;
   keepAlive?: boolean;
+
+  /**
+   * When this flag is enabled, any subsequent commands issued by this client are guaranteed to observe the effects of all earlier writes submitted by the same client.
+   */
+  readYourWrites?: boolean;
 } & core.RedisOptions &
   RequesterConfig;
 
@@ -48,15 +53,11 @@ export class Redis extends core.Redis {
    */
   constructor(config: RedisConfigFastly) {
     if (!config.url) {
-      throw new Error(
-        `[Upstash Redis] The 'url' property is missing or undefined in your Redis config.`
-      );
+      throw new Error(`[Upstash Redis] The 'url' property is missing or undefined in your Redis config.`)
     }
 
     if (!config.token) {
-      throw new Error(
-        `[Upstash Redis] The 'token' property is missing or undefined in your Redis config.`
-      );
+      throw new Error(`[Upstash Redis] The 'token' property is missing or undefined in your Redis config.`)
     }
 
     if (config.url.startsWith(" ") || config.url.endsWith(" ") || /\r|\n/.test(config.url)) {
@@ -73,6 +74,7 @@ export class Redis extends core.Redis {
       options: { backend: config.backend },
       responseEncoding: config.responseEncoding,
       keepAlive: config.keepAlive,
+      readYourWrites: config.readYourWrites,
     });
 
     super(client, {

diff --git a/platforms/nodejs.ts b/platforms/nodejs.ts
@@ -53,6 +53,11 @@ export type RedisConfigNodejs = {
   latencyLogging?: boolean;
   agent?: unknown;
   keepAlive?: boolean;
+
+  /**
+   * When this flag is enabled, any subsequent commands issued by this client are guaranteed to observe the effects of all earlier writes submitted by the same client.
+   */
+  readYourWrites?: boolean;
 } & core.RedisOptions &
   RequesterConfig;
 
@@ -97,15 +102,11 @@ export class Redis extends core.Redis {
     }
 
     if (!configOrRequester.url) {
-      throw new Error(
-        `[Upstash Redis] The 'url' property is missing or undefined in your Redis config.`
-      );
+      throw new Error(`[Upstash Redis] The 'url' property is missing or undefined in your Redis config.`)
     }
 
     if (!configOrRequester.token) {
-      throw new Error(
-        `[Upstash Redis] The 'token' property is missing or undefined in your Redis config.`
-      );
+      throw new Error(`[Upstash Redis] The 'token' property is missing or undefined in your Redis config.`)
     }
 
     if (
@@ -133,6 +134,7 @@ export class Redis extends core.Redis {
       cache: configOrRequester.cache ?? "no-store",
       signal: configOrRequester.signal,
       keepAlive: configOrRequester.keepAlive,
+      readYourWrites: configOrRequester.readYourWrites,
     });
 
     super(client, {