feat(middleware-retry): call retry strategy based on value in retryMode

Author: trivikr

packages/middleware-retry/src/configurations.ts

@@ -1,7 +1,8 @@
 import { LoadedConfigSelectors } from "@aws-sdk/node-config-provider";
 import { Provider, RetryStrategy } from "@aws-sdk/types";
 
-import { DEFAULT_MAX_ATTEMPTS, DEFAULT_RETRY_MODE } from "./config";
+import { AdaptiveRetryStrategy } from "./AdaptiveRetryStrategy";
+import { DEFAULT_MAX_ATTEMPTS, DEFAULT_RETRY_MODE, RETRY_MODES } from "./config";
 import { StandardRetryStrategy } from "./StandardRetryStrategy";
 
 export const ENV_MAX_ATTEMPTS = "AWS_MAX_ATTEMPTS";
@@ -38,6 +39,15 @@ export interface RetryInputConfig {
    * The strategy to retry the request. Using built-in exponential backoff strategy by default.
    */
   retryStrategy?: RetryStrategy;
+  /**
+   * Specifies which retry algorithm to use.
+   */
+  retryMode?: string;
+  /**
+   * Specifies provider for retry algorithm to use.
+   * @internal
+   */
+  retryModeProvider: Provider<string>;
 }
 
 interface PreviouslyResolved {}
@@ -49,15 +59,24 @@ export interface RetryResolvedConfig {
   /**
    * Resolved value for input config {@link RetryInputConfig.retryStrategy}
    */
-  retryStrategy: RetryStrategy;
+  retryStrategy: Provider<RetryStrategy>;
 }
 
 export const resolveRetryConfig = <T>(input: T & PreviouslyResolved & RetryInputConfig): T & RetryResolvedConfig => {
   const maxAttempts = normalizeMaxAttempts(input.maxAttempts);
   return {
     ...input,
     maxAttempts,
-    retryStrategy: input.retryStrategy || new StandardRetryStrategy(maxAttempts),
+    retryStrategy: async () => {
+      if (input.retryStrategy) {
+        return input.retryStrategy;
+      }
+      const retryMode = input.retryMode || (await input.retryModeProvider());
+      if (retryMode === RETRY_MODES.adaptive) {
+        return new AdaptiveRetryStrategy(maxAttempts);
+      }
+      return new StandardRetryStrategy(maxAttempts);
+    },
   };
 };
 

packages/middleware-retry/src/retryMiddleware.ts

@@ -17,9 +17,9 @@ export const retryMiddleware = (options: RetryResolvedConfig) => <Output extends
 ): FinalizeHandler<any, Output> => async (
   args: FinalizeHandlerArguments<any>
 ): Promise<FinalizeHandlerOutput<Output>> => {
-  if (options?.retryStrategy?.mode)
-    context.userAgent = [...(context.userAgent || []), ["cfg/retry-mode", options.retryStrategy.mode]];
-  return options.retryStrategy.retry(next, args);
+  const retryStrategy = await options.retryStrategy();
+  if (retryStrategy?.mode) context.userAgent = [...(context.userAgent || []), ["cfg/retry-mode", retryStrategy.mode]];
+  return retryStrategy.retry(next, args);
 };
 
 export const retryMiddlewareOptions: FinalizeRequestHandlerOptions & AbsoluteLocation = {