NPM package to implement Retry Pattern in your nodejs applications. Created from this Cookiecutter Template.
- Uses the builder pattern, implementation inspired by resilience4j.
- Uses the fail4ward service docker image to run a service to test with.
- Uses testcontainers-node to test against a running docker service.
- Supports
UntilLimitstrategy. Based on the Medium article SRE: Resiliency: Retries in Action — Availability in Exchange for Latency
Tested on:
- npm 6.13.4
- node v10.19.0
npm install --save fail4ward-retry
Import what we need.
import { RetryConfigBuilder, RetryConfig, Retry, UntilLimit } from 'fail4ward-retry';Set the configuration using the RetryConfigBuilder().
const maxAttempts = 5;
const waitDuration = 1000;
const retryConfig: RetryConfig = new RetryConfigBuilder()
.withMaxAttempts(maxAttempts)
.withWaitDuration(waitDuration)
.withStrategy(UntilLimit)
.build();Builder properties we are setting
withMaxAttempts()number of attempts to retry.withWaitDuration()backoff time in milliseconds.withStrategy()retry strategy to use. This package currently supportsUntilLimit.
Decorate the function that calls your service using the retryConfig instantiated with Retry.decoratePromise().
const retry = Retry.With(retryConfig);
const fn = retry.decoratePromise(failingFn);Below is an example of the failingFn calls an API. Similar functions can be found in the /example and /__tests__ folders.
Click to see failingFn()
async function failingFn() {
const url = 'http://localhost:8000/error';
try {
const res = await fetch(url);
const {status} = res;
if (status === 500) {
throw new Error('server error');
}
return res;
} catch(e) {
throw new Error(e);
}
}Call the function that fetches the response from your API and retrieve the response.
try {
const res = await fn();
const retryResponse = await res.json();
console.log('retryResponse: ', retryResponse);
} catch(e) {
console.log(e);
}-
Checkout the repo
git clone [email protected]:ardydedase/fail4ward-retry.git -
Change directory to the
examplefoldercd example/ -
Install dependencies
npm install -
Run a test service
docker run --name fail-svc -p 8000:8000 -it ardydedase/fail4ward:latest -
Run the example file
npm run dev
-
Checkout the repo
git clone [email protected]:ardydedase/fail4ward-retry.git -
Install dependencies
npm install -
Run build. This will generate the compiled code with type definitions in the
distfolder.npm run build -
Formatting and linting.
npm run lint npm run format -
Run tests
npm test
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