Spaces:
Running
Running
File size: 4,267 Bytes
5c2ed06 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 |
# Retry utility
by [Nicholas C. Zakas](https://humanwhocodes.com)
If you find this useful, please consider supporting my work with a [donation](https://humanwhocodes.com/donate) or [nominate me](https://stars.github.com/nominate/) for a GitHub Star.
## Description
A utility for retrying failed async JavaScript calls based on the error returned.
## Usage
### Node.js
Install using [npm][npm] or [yarn][yarn]:
```
npm install @humanwhocodes/retry
# or
yarn add @humanwhocodes/retry
```
Import into your Node.js project:
```js
// CommonJS
const { Retrier } = require("@humanwhocodes/retry");
// ESM
import { Retrier } from "@humanwhocodes/retry";
```
### Deno
Install using [JSR](https://jsr.io):
```shell
deno add @humanwhocodes/retry
#or
jsr add @humanwhocodes/retry
```
Then import into your Deno project:
```js
import { Retrier } from "@humanwhocodes/retry";
```
### Bun
Install using this command:
```
bun add @humanwhocodes/retry
```
Import into your Bun project:
```js
import { Retrier } from "@humanwhocodes/retry";
```
### Browser
It's recommended to import the minified version to save bandwidth:
```js
import { Retrier } from "https://cdn.skypack.dev/@humanwhocodes/retry?min";
```
However, you can also import the unminified version for debugging purposes:
```js
import { Retrier } from "https://cdn.skypack.dev/@humanwhocodes/retry";
```
## API
After importing, create a new instance of `Retrier` and specify the function to run on the error. This function should return `true` if you want the call retried and `false` if not.
```js
// this instance will retry if the specific error code is found
const retrier = new Retrier(error => {
return error.code === "ENFILE" || error.code === "EMFILE";
});
```
Then, call the `retry()` method around the function you'd like to retry, such as:
```js
import fs from "fs/promises";
const retrier = new Retrier(error => {
return error.code === "ENFILE" || error.code === "EMFILE";
});
const text = await retrier.retry(() => fs.readFile("README.md", "utf8"));
```
The `retry()` method will either pass through the result on success or wait and retry on failure. Any error that isn't caught by the retrier is automatically rejected so the end result is a transparent passing through of both success and failure.
### Setting a Timeout
You can control how long a task will attempt to retry before giving up by passing the `timeout` option to the `Retrier` constructor. By default, the timeout is one minute.
```js
import fs from "fs/promises";
const retrier = new Retrier(error => {
return error.code === "ENFILE" || error.code === "EMFILE";
}, { timeout: 100_000 });
const text = await retrier.retry(() => fs.readFile("README.md", "utf8"));
```
When a call times out, it rejects the first error that was received from calling the function.
### Setting a Concurrency Limit
When processing a large number of function calls, you can limit the number of concurrent function calls by passing the `concurrency` option to the `Retrier` constructor. By default, `concurrency` is 1000.
```js
import fs from "fs/promises";
const retrier = new Retrier(error => {
return error.code === "ENFILE" || error.code === "EMFILE";
}, { concurrency: 100 });
const filenames = getFilenames();
const contents = await Promise.all(
filenames.map(filename => retrier.retry(() => fs.readFile(filename, "utf8"))
);
```
### Aborting with `AbortSignal`
You can also pass an `AbortSignal` to cancel a retry:
```js
import fs from "fs/promises";
const controller = new AbortController();
const retrier = new Retrier(error => {
return error.code === "ENFILE" || error.code === "EMFILE";
});
const text = await retrier.retry(
() => fs.readFile("README.md", "utf8"),
{ signal: controller.signal }
);
```
## Developer Setup
1. Fork the repository
2. Clone your fork
3. Run `npm install` to setup dependencies
4. Run `npm test` to run tests
### Debug Output
Enable debugging output by setting the `DEBUG` environment variable to `"@hwc/retry"` before running.
## License
Apache 2.0
## Prior Art
This utility is inspired by, and contains code from [`graceful-fs`](https://github.com/isaacs/node-graceful-fs).
[npm]: https://npmjs.com/
[yarn]: https://yarnpkg.com/
|