# fail4ward-retry > fail4ward-retry Latest version **0.2.3** (published 2020-06-12) · ISC license · 0 weekly downloads ## Install ```sh npm install fail4ward-retry pnpm add fail4ward-retry yarn add fail4ward-retry bun add fail4ward-retry ``` ## Health **Score 25/100 (F)** — status: abandoned. Positive: has types; no vulnerabilities; high quality score. Warnings: low downloads; no esm support; pre 1.0. Negative: abandoned; low maintenance score. ## Facts | | | |---|---| | Version | 0.2.3 | | Published | 2020-06-12 | | First published | 2020-06-02 | | Weekly downloads | 0 | | License | ISC | | TypeScript types | bundled | | Module format | CommonJS | | Dependencies | 3 | | Unpacked size | 11 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 1 | | Maintainers | ardydedase | ## Links - npm: https://www.npmjs.com/package/fail4ward-retry - Repository: https://github.com/ardydedase/fail4ward-retry - Homepage: https://github.com/ardydedase/fail4ward-retry#readme - Issues: https://github.com/ardydedase/fail4ward-retry/issues - npm.io page: https://npm.io/package/fail4ward-retry ## Dependencies (3) - [rxjs](https://npm.io/package/rxjs.md) ^6.5.5 - [node-fetch](https://npm.io/package/node-fetch.md) ^2.6.0 - [@types/node-fetch](https://npm.io/package/@types/node-fetch.md) ^2.5.6 ## Recent versions - 0.2.3 (latest) — 2020-06-12 - 0.2.2 — 2020-06-11 - 0.2.1 — 2020-06-11 - 0.2.0 — 2020-06-10 - 0.1.9 — 2020-06-09 - 0.1.8 — 2020-06-09 - 0.1.7 — 2020-06-09 - 0.1.6 — 2020-06-07 - 0.1.5 — 2020-06-07 - 0.1.4 — 2020-06-07 - 0.1.3 — 2020-06-06 - 0.1.2 — 2020-06-06 - 0.1.1 — 2020-06-04 - 0.1.0 — 2020-06-02 ## README # fail4ward-retry NPM package to implement Retry Pattern in your nodejs applications. Created from this [Cookiecutter Template](https://github.com/ardydedase/cookiecutter-npm-package). [![CI](https://github.com/ardydedase/fail4ward-retry/workflows/CI/badge.svg?branch=master)](https://github.com/ardydedase/fail4ward-retry/actions?query=workflow%3ACI) [![npm-publish](https://github.com/ardydedase/fail4ward-retry/workflows/npm-publish/badge.svg?branch=master)](https://github.com/ardydedase/fail4ward-retry/actions?query=workflow%3Anpm-publish) [![npm-install-and-use-package](https://github.com/ardydedase/fail4ward-retry/workflows/npm-install-and-use-package/badge.svg)](https://github.com/ardydedase/fail4ward-retry/actions?query=workflow%3Anpm-install-and-use-package) [![NPM](https://nodei.co/npm/fail4ward-retry.png?downloads=true&downloadRank=true&stars=true)](https://nodei.co/npm/fail4ward-retry/) ## Features - Uses the builder pattern, implementation is similar to `resilience4j`. - Uses the [ardydedase/fail4ward](https://hub.docker.com/repository/docker/ardydedase/fail4ward) docker image to run a service to test with. - Uses [testcontainers-node](https://github.com/testcontainers/testcontainers-node) to test against a running docker service. - Supports `UntilLimit` strategy. Based on the Medium article [SRE: Resiliency: Retries in Action — Availability in Exchange for Latency](https://medium.com/dm03514-tech-blog/sre-resiliency-retries-in-action-using-js-8e4b7e7d4526) ## Specs Tested on: - npm 6.13.4 - node v10.19.0 ## Installation ``` npm install --save fail4ward-retry ``` ## Usage Import what we need. ```ts import { RetryConfigBuilder, RetryConfig, Retry, UntilLimit } from 'fail4ward-retry'; ``` Set the configuration using the `RetryConfigBuilder()`. ```ts 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 supports `UntilLimit`. Decorate the function that calls your service using the retryConfig instantiated with `Retry.decoratePromise()`. ```ts 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](/example) and [/\_\_tests\_\_](/__tests__) folders.
Click to see failingFn() ```ts 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. ```ts try { const res = await fn(); const retryResponse = await res.json(); console.log('retryResponse: ', retryResponse); } catch(e) { console.log(e); } ``` ## Run the example 1. Checkout the repo git clone git@github.com:ardydedase/fail4ward-retry.git 1. Change directory to the `example` folder cd example/ 1. Install dependencies npm install 1. Run a test service docker run --name fail-svc -p 8000:8000 -it ardydedase/fail4ward:latest 1. Run the example file npm run dev ## Development 1. Checkout the repo git clone git@github.com:ardydedase/fail4ward-retry.git 1. Install dependencies npm install 1. Run build. This will generate the compiled code with type definitions in the `dist` folder. npm run build 1. Formatting and linting. npm run lint npm run format 1. Run tests npm test ## Credits - https://medium.com/better-programming/lets-look-at-the-builder-pattern-in-typescript-fb9cf202c04d - https://medium.com/dm03514-tech-blog/sre-resiliency-retries-in-action-using-js-8e4b7e7d4526 - https://medium.com/cameron-nokes/the-30-second-guide-to-publishing-a-typescript-package-to-npm-89d93ff7bccd --- _Source: https://npm.io/package/fail4ward-retry · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._