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Poll without hammering the server – use the exponential backoff algorithm to space out retries
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| /** | |
| * A configuration object for `pollWithExponentialBackoff` | |
| */ | |
| interface IPollOptions { | |
| /** | |
| * A callback that will be run on every poll attempt | |
| */ | |
| executor: () => Promise<any> | |
| /** | |
| * A callback that will be run after each poll attempt to check if further | |
| * attempts can be cancelled | |
| */ | |
| watcher: (result: any) => boolean | |
| /** | |
| * The interval base | |
| */ | |
| intervalBase: number | |
| /** | |
| * The interval multiplier | |
| */ | |
| intervalMultiplier: number | |
| /** | |
| * The maximum number of poll attempts | |
| */ | |
| maxAttempts: number | |
| } | |
| /** | |
| * Poll without hammering the server – use the exponential backoff algorithm to | |
| * space out retries | |
| * | |
| * @see {@link https://en.wikipedia.org/wiki/Exponential_backoff | Wikipedia} | |
| * to learn more about the exponential backoff algorithm | |
| * | |
| * @example Polling an image server to check if a batch upload is processed | |
| * ``` | |
| * let jobLogDetails = null | |
| * try { | |
| * jobLogDetails = await pollWithExponentialBackoff({ | |
| * executor: async () => await client.getJobLogDetails({companyHandle, jobName}), | |
| * watcher: (jobLogArray) => jobLogArray?.items[0]?.endDate, | |
| * intervalBase: 500, | |
| * intervalMultiplier: 2, | |
| * maxAttempts: 10, | |
| * }) | |
| * } catch (error) { | |
| * console.log(`Error fetching job log details: ${error}`) | |
| * } | |
| * ``` | |
| * | |
| * @param options - A configuration object | |
| * @returns A promise that resolves to the poll result (i.e., the response | |
| * received from the server) | |
| */ | |
| async function pollWithExponentialBackoff(options: IPollOptions): Promise<any> { | |
| const { | |
| executor, | |
| watcher, | |
| intervalBase, | |
| intervalMultiplier, | |
| maxAttempts, | |
| } = options | |
| let attemptsSoFar = 0 | |
| const runPoll = async ( | |
| resolve: (value: any) => any, | |
| reject: (reason: Error) => any | |
| ) => { | |
| const result = await executor() | |
| attemptsSoFar += 1 | |
| if (watcher(result)) { | |
| return resolve(result) | |
| } | |
| if (maxAttempts && attemptsSoFar === maxAttempts) { | |
| return reject(new Error('Exceeded max attempts')) | |
| } | |
| setTimeout( | |
| runPoll, | |
| intervalBase * intervalMultiplier ** attemptsSoFar, | |
| resolve, | |
| reject | |
| ) | |
| } | |
| return new Promise(runPoll) | |
| } |
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