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node_modules/@azure/msal-node/src/retry/DefaultManagedIdentityRetryPolicy.ts

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