71 lines
2.5 KiB
TypeScript
71 lines
2.5 KiB
TypeScript
/*
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License.
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*/
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import { IncomingHttpHeaders } from "http";
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import { HttpStatus, Logger } from "@azure/msal-common";
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import { IHttpRetryPolicy } from "./IHttpRetryPolicy.js";
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import { LinearRetryStrategy } from "./LinearRetryStrategy.js";
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export const DEFAULT_MANAGED_IDENTITY_MAX_RETRIES: number = 3; // referenced in unit test
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const DEFAULT_MANAGED_IDENTITY_RETRY_DELAY_MS: number = 1000;
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const DEFAULT_MANAGED_IDENTITY_HTTP_STATUS_CODES_TO_RETRY_ON: Array<number> = [
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HttpStatus.NOT_FOUND,
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HttpStatus.REQUEST_TIMEOUT,
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HttpStatus.TOO_MANY_REQUESTS,
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HttpStatus.SERVER_ERROR,
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HttpStatus.SERVICE_UNAVAILABLE,
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HttpStatus.GATEWAY_TIMEOUT,
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];
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export class DefaultManagedIdentityRetryPolicy implements IHttpRetryPolicy {
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/*
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* this is defined here as a static variable despite being defined as a constant outside of the
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* class because it needs to be overridden in the unit tests so that the unit tests run faster
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*/
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static get DEFAULT_MANAGED_IDENTITY_RETRY_DELAY_MS(): number {
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return DEFAULT_MANAGED_IDENTITY_RETRY_DELAY_MS;
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}
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private linearRetryStrategy: LinearRetryStrategy =
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new LinearRetryStrategy();
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async pauseForRetry(
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httpStatusCode: number,
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currentRetry: number,
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logger: Logger,
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retryAfterHeader: IncomingHttpHeaders["retry-after"]
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): Promise<boolean> {
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if (
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DEFAULT_MANAGED_IDENTITY_HTTP_STATUS_CODES_TO_RETRY_ON.includes(
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httpStatusCode
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) &&
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currentRetry < DEFAULT_MANAGED_IDENTITY_MAX_RETRIES
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) {
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const retryAfterDelay: number =
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this.linearRetryStrategy.calculateDelay(
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retryAfterHeader,
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DefaultManagedIdentityRetryPolicy.DEFAULT_MANAGED_IDENTITY_RETRY_DELAY_MS
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);
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logger.verbose(
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`Retrying request in ${retryAfterDelay}ms (retry attempt: ${
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currentRetry + 1
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})`
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);
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// pause execution for the calculated delay
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await new Promise((resolve) => {
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// retryAfterHeader value of 0 evaluates to false, and DEFAULT_MANAGED_IDENTITY_RETRY_DELAY_MS will be used
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return setTimeout(resolve, retryAfterDelay);
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});
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return true;
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}
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// if the status code is not retriable or max retries have been reached, do not retry
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return false;
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}
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}
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