Add jitter support to BackOff class

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Fedor Indutny 2021-09-28 15:12:43 -07:00 committed by GitHub
parent 1191288107
commit cd710bb8d2
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3 changed files with 56 additions and 4 deletions

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@ -42,4 +42,32 @@ describe('BackOff', () => {
assert.strictEqual(b.getAndIncrement(), 1);
assert.strictEqual(b.getAndIncrement(), 2);
});
it('should apply jitter', () => {
const b = new BackOff([1, 2, 3], {
jitter: 1,
random: () => 0.5,
});
assert.strictEqual(b.getIndex(), 0);
assert.strictEqual(b.isFull(), false);
assert.strictEqual(b.get(), 1);
assert.strictEqual(b.getAndIncrement(), 1);
assert.strictEqual(b.get(), 2.5);
assert.strictEqual(b.getIndex(), 1);
assert.strictEqual(b.isFull(), false);
assert.strictEqual(b.getAndIncrement(), 2.5);
assert.strictEqual(b.getIndex(), 2);
assert.strictEqual(b.isFull(), true);
assert.strictEqual(b.getAndIncrement(), 3.5);
assert.strictEqual(b.getIndex(), 2);
assert.strictEqual(b.isFull(), true);
assert.strictEqual(b.getAndIncrement(), 3.5);
assert.strictEqual(b.getIndex(), 2);
assert.strictEqual(b.isFull(), true);
});
});

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@ -32,6 +32,8 @@ const TEN_SECONDS = 10 * durations.SECOND;
const FIVE_MINUTES = 5 * durations.MINUTE;
const JITTER = 5 * durations.SECOND;
export type SocketManagerOptions = Readonly<{
url: string;
certificateAuthority: string;
@ -54,7 +56,9 @@ export type SocketManagerOptions = Readonly<{
// Incoming requests on unauthenticated resource are not currently supported.
// WebSocketResource is responsible for their immediate termination.
export class SocketManager extends EventListener {
private backOff = new BackOff(FIBONACCI_TIMEOUTS);
private backOff = new BackOff(FIBONACCI_TIMEOUTS, {
jitter: JITTER,
});
private authenticated?: AbortableProcess<WebSocketResource>;
@ -199,7 +203,7 @@ export class SocketManager extends EventListener {
return;
}
if (code !== 500 && code !== -1) {
if (!(code >= 500 && code <= 599) && code !== -1) {
// No reconnect attempt should be made
return;
}

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@ -15,13 +15,33 @@ export const FIBONACCI_TIMEOUTS: ReadonlyArray<number> = [
55 * SECOND,
];
export type BackOffOptionsType = Readonly<{
jitter?: number;
// Testing
random?: () => number;
}>;
const DEFAULT_RANDOM = () => Math.random();
export class BackOff {
private count = 0;
constructor(private readonly timeouts: ReadonlyArray<number>) {}
constructor(
private readonly timeouts: ReadonlyArray<number>,
private readonly options: BackOffOptionsType = {}
) {}
public get(): number {
return this.timeouts[this.count];
let result = this.timeouts[this.count];
const { jitter = 0, random = DEFAULT_RANDOM } = this.options;
// Do not apply jitter larger than the timeout value. It is supposed to be
// activated for longer timeouts.
if (jitter < result) {
result += random() * jitter;
}
return result;
}
public getAndIncrement(): number {