What is @aws-sdk/util-retry?
The @aws-sdk/util-retry package is part of the AWS SDK for JavaScript v3. It provides utilities to add retry functionality to the AWS SDK operations. This package is designed to help manage retries in a more efficient and customizable way, allowing developers to handle transient errors by repeating requests without having to implement their own retry logic.
What are @aws-sdk/util-retry's main functionalities?
Configuring retry strategies
This feature allows developers to configure retry strategies, specifying how many times an operation should be retried before giving up. The `StandardRetryStrategy` is a built-in strategy that can be used to automatically handle retries according to the SDK's standard logic.
const { StandardRetryStrategy } = require('@aws-sdk/util-retry');
const retryStrategy = new StandardRetryStrategy(maxAttempts);
Custom retry strategy
Developers can extend the `RetryStrategy` class to implement custom retry logic. This allows for fine-grained control over when and how retries should be performed, based on the specific needs of the application.
const { RetryStrategy } = require('@aws-sdk/util-retry');
class MyRetryStrategy extends RetryStrategy {
constructor(maxAttempts) {
super();
this.maxAttempts = maxAttempts;
}
shouldRetry(error) {
// Custom logic to determine if a retry should be attempted
}
delayBeforeNextRetry(retryCount) {
// Custom logic to determine the delay before the next retry
}
}
Other packages similar to @aws-sdk/util-retry
retry
The `retry` package provides a simple, yet powerful abstraction for retrying asynchronous operations. Unlike @aws-sdk/util-retry, which is designed specifically for AWS SDK operations, `retry` can be used for any asynchronous operation, making it more versatile but less specialized.
async-retry
Similar to `retry`, `async-retry` is a lightweight library for retrying promises. It offers a simple API and flexible configuration options. While `async-retry` is more focused on promise-based operations, @aws-sdk/util-retry is tailored for AWS SDK operations, providing more specific functionalities for handling AWS service interactions.
p-retry
The `p-retry` package is designed for retrying promises with a specific focus on simplicity and composability. It uses a declarative approach for defining retry conditions and strategies. Compared to @aws-sdk/util-retry, `p-retry` is more generic and can be applied to any promise-based operation, not just AWS SDK calls.
@aws-sdk/util-retry
This package provides shared utilities for retries.
Usage
Default
By default, each client already has a default retry strategy. The default retry count is 3, and
only retryable errors will be retried.
AWS Documentation: Retry behavior.
import { S3Client } from "@aws-sdk/client-s3";
const client = new S3Client({});
MaxAttempts
If you want to change the number of attempts, you can provide maxAttempts
configuration during client creation.
import { S3Client } from "@aws-sdk/client-s3";
const client = new S3Client({ maxAttempts: 4 });
This is recommended because the StandardRetryStrategy
includes backoff calculation,
deciding whether an error should be retried, and a retry token counter.
MaxAttempts and BackoffComputation
If you want to change the number of attempts and use a custom delay
computation, you can use the ConfiguredRetryStrategy
from @aws-sdk/util-retry
.
import { S3Client } from "@aws-sdk/client-s3";
import { ConfiguredRetryStrategy } from "@aws-sdk/util-retry";
const client = new S3Client({
retryStrategy: new ConfiguredRetryStrategy(
4,
(attempt: number) => 100 + attempt * 1000
),
});
This example sets the backoff at 100ms plus 1s per attempt.
MaxAttempts and RetryStrategy
If you provide both maxAttempts
and retryStrategy
, the retryStrategy
will
get precedence as it's more specific.
import { S3Client } from "@aws-sdk/client-s3";
import { ConfiguredRetryStrategy } from "@aws-sdk/util-retry";
const client = new S3Client({
maxAttempts: 2,
retryStrategy: new ConfiguredRetryStrategy(
4,
(attempt: number) => 100 + attempt * 1000
),
});
Further customization
You can implement the RetryStrategyV2
interface.
https://github.com/aws/aws-sdk-js-v3/blob/main/packages/types/src/retry.ts