feat: AbortSignal support for connect() (#519)

Author: uki00a

README.md

@@ -92,6 +92,19 @@ To consume a redis cluster, you can use
 
 ## Advanced Usage
 
+### Handle connection timeout
+
+Connection timeout handling can be implemented with `signal` option:
+
+```ts
+import { connect } from "@db/redis";
+
+using redis = await connect({
+  hostname: "127.0.0.1",
+  signal: () => AbortSignal.timeout(5_000),
+});
+```
+
 ### Retriable connection
 
 By default, a client's connection will retry a command execution based on

connection.ts

@@ -83,6 +83,13 @@ export interface RedisConnectionOptions {
    */
   healthCheckInterval?: number;
 
+  /**
+   * An {@linkcode AbortSignal} which is returned by this function is used to abort an ongoing connection process. With this option, you can implement connection timeout, etc.
+   *
+   * Works only in Deno v2.3 or later.
+   */
+  signal?: () => AbortSignal;
+
   /**
    * @private
    */
@@ -264,9 +271,12 @@ class RedisConnection
 
   async #connect(retryCount: number) {
     try {
+      const signal: AbortSignal | undefined = this.options?.signal?.() ??
+        undefined;
       const dialOpts: Deno.ConnectOptions = {
         hostname: this.hostname,
         port: parsePortLike(this.port),
+        signal,
       };
       const conn: Deno.Conn = this.options?.tls || this.options?.caCerts != null
         ? await Deno.connectTls({ ...dialOpts, caCerts: this.options?.caCerts })

tests/commands/connection.ts

@@ -4,6 +4,7 @@ import {
   assertEquals,
   assertExists,
   assertInstanceOf,
+  assertRejects,
 } from "../../deps/std/assert.ts";
 import { afterAll, beforeAll, describe, it } from "../../deps/std/testing.ts";
 import { delay } from "../../deps/std/async.ts";
@@ -123,6 +124,17 @@ export function connectionTests(
       client.close();
     });
 
+    it("supports AbortSignal", async () => {
+      const ac = new AbortController();
+      ac.abort();
+      const error = await assertRejects(async () =>
+        await connect({
+          ...getOpts(),
+          signal: () => ac.signal,
+        }), DOMException);
+      assertEquals(error.name, "AbortError");
+    });
+
     it("works with a lazy client", async () => {
       const client = createLazyClient(getOpts());
       assert(!client.isConnected);