add exponential backoff option to reconnect plugin (#15)

* feat(plugins/reconnect): add exponential backoff option

* test(plugins/antiflood): reduce delay used in test

* chore(deps): upgrade to [email protected]

Author: jeromeludmann

API.md

@@ -335,7 +335,7 @@ const client = new Client({
 
 Enables auto reconnect.
 
-Takes boolean or `{ attempts?: number, delay?: number }`.
+Takes a boolean or `{ attempts?: number, delay?: number, exponentialBackoff?: boolean }`.
 
 Default to `false` or `{ attempts: 10, delay: 5 }` if set to `true`.
 
@@ -358,6 +358,18 @@ const client = new Client({
 });
 ```
 
+Tries to reconnect `5` times with an initial delay of `3` seconds with an exponential backoff:
+
+```ts
+const client = new Client({
+  reconnect: {
+    attempts: 5,
+    delay: 3,
+    exponentialBackoff: true,
+  },
+});
+```
+
 ### option: resolveInvalidNames
 
 Auto resolve invalid names (for nick and username).

deps.ts

@@ -4,13 +4,13 @@ export {
   green,
   red,
   stripColor,
-} from "https://deno.land/std@0.203.0/fmt/colors.ts";
+} from "https://deno.land/std@0.224.0/fmt/colors.ts";
 
-export { assertArrayIncludes } from "https://deno.land/std@0.203.0/assert/assert_array_includes.ts";
-export { assertEquals } from "https://deno.land/std@0.203.0/assert/assert_equals.ts";
-export { assertExists } from "https://deno.land/std@0.203.0/assert/assert_exists.ts";
-export { assertMatch } from "https://deno.land/std@0.203.0/assert/assert_match.ts";
-export { assertRejects } from "https://deno.land/std@0.203.0/assert/assert_rejects.ts";
-export { assertThrows } from "https://deno.land/std@0.203.0/assert/assert_throws.ts";
+export { assertArrayIncludes } from "https://deno.land/std@0.224.0/assert/assert_array_includes.ts";
+export { assertEquals } from "https://deno.land/std@0.224.0/assert/assert_equals.ts";
+export { assertExists } from "https://deno.land/std@0.224.0/assert/assert_exists.ts";
+export { assertMatch } from "https://deno.land/std@0.224.0/assert/assert_match.ts";
+export { assertRejects } from "https://deno.land/std@0.224.0/assert/assert_rejects.ts";
+export { assertThrows } from "https://deno.land/std@0.224.0/assert/assert_throws.ts";
 
 export { Queue } from "https://deno.land/x/[email protected]/mod.ts";

plugins/antiflood_test.ts

@@ -4,7 +4,7 @@ import { mock } from "../testing/mock.ts";
 
 describe("plugins/antiflood", (test) => {
   test("send two PRIVMSG with delay", async () => {
-    const { client, server } = await mock({ floodDelay: 250 });
+    const { client, server } = await mock({ floodDelay: 10 });
 
     client.privmsg("#channel", "Hello world");
     client.privmsg("#channel", "Hello world, again");
@@ -16,7 +16,7 @@ describe("plugins/antiflood", (test) => {
     ]);
 
     // Wait for second message to make it through
-    await delay(1000);
+    await delay(100);
     raw = server.receive();
 
     // Second message now dispatched to server

plugins/reconnect.ts

@@ -6,7 +6,7 @@ interface ReconnectFeatures {
   options: {
     /** Enables auto reconnect.
      *
-     * Takes `boolean` or `{ attempts?: number, delay?: number }`.
+     * Takes a boolean or `{ attempts?: number, delay?: number, exponentialBackoff?: boolean }`.
      *
      * Default to `false` or `{ attempts: 10, delay: 5 }` if set to `true`. */
     reconnect?: boolean | {
@@ -19,16 +19,22 @@ interface ReconnectFeatures {
        *
        * Default to `5` seconds. */
       delay?: number;
+
+      /** Enables exponential backoff.
+       *
+       * Default to `false`. */
+      exponentialBackoff?: boolean;
     };
   };
   events: {
-    "reconnecting": RemoteAddr;
+    reconnecting: RemoteAddr;
   };
 }
 
 const DEFAULT_RECONNECT = false;
 const DEFAULT_ATTEMPTS = 10;
 const DEFAULT_DELAY = 5;
+const DEFAULT_BACKOFF_FACTOR = { STATIC: 1, EXPONENTIAL: 2 };
 
 export default createPlugin(
   "reconnect",
@@ -44,11 +50,16 @@ export default createPlugin(
   const {
     attempts = DEFAULT_ATTEMPTS,
     delay = DEFAULT_DELAY,
+    exponentialBackoff,
   } = config;
 
   let currentAttempts = 0;
   let timeout: number | undefined;
 
+  const backoffFactor = exponentialBackoff
+    ? DEFAULT_BACKOFF_FACTOR.EXPONENTIAL
+    : DEFAULT_BACKOFF_FACTOR.STATIC;
+
   const delayReconnect = () => {
     clearTimeout(timeout);
     if (currentAttempts === attempts) return;
@@ -59,7 +70,7 @@ export default createPlugin(
     const { hostname, port, tls } = remoteAddr;
     timeout = setTimeout(
       async () => await client.connect(hostname, port, tls),
-      delay * 1000,
+      delay * 1000 * Math.pow(backoffFactor, currentAttempts - 1),
     );
   };
 

plugins/reconnect_test.ts

@@ -19,6 +19,8 @@ describe("plugins/reconnect", (test) => {
     await client.once("reconnecting");
 
     assertEquals(reconnecting, 1);
+
+    await client.once("error"); // wait for timeout clearing
   });
 
   test("reconnect on server error", async () => {
@@ -36,6 +38,8 @@ describe("plugins/reconnect", (test) => {
     await client.once("reconnecting");
 
     assertEquals(reconnecting, 1);
+
+    await client.once("connecting"); // wait for timeout clearing
   });
 
   test("reset attemps when RPL_WELCOME is received", async () => {
@@ -67,6 +71,8 @@ describe("plugins/reconnect", (test) => {
     await client.once("reconnecting");
 
     assertEquals(reconnecting, 3);
+
+    await client.once("connecting"); // wait for timeout clearing
   });
 
   test("not reconnect if disabled", async () => {

testing/conn.ts

@@ -61,4 +61,6 @@ export class MockConn extends EventEmitter<Events> implements Deno.Conn {
   ref(): void {}
 
   unref(): void {}
+
+  [Symbol.dispose](): void {}
 }