express-chaos-middleware
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Put some chaos in your express application
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# express-chaos-middleware
Put some chaos in your express application.
## Description
The aim of this library is to provide simple chaos testing cases for express applications.
## Installation
```sh
npm add express-chaos-middleware
```
## Features
- Requests slowdown : Endpoints can be slowed down randomly
- Random response error : Endpoints can respond randomly with an error code
- Random exception : Endpoints can throw exceptions randomly
- Seeding : Manage random to replay scenarios
Chaos features have a 10 percent "chance" of being called by default. The percentage can be changed in the configuration object.
## Usage
### Simple usage
```js
const {chaos} = require('express-chaos-middleware');
app.use(chaos())
```
### Use an existing seed
The random seed can be configured in the input object param.
```js
const {chaos} = require('express-chaos-middleware');
app.use(chaos({
// this seed throw an exception on the first call
seed: 'uJaK8BUr2084pph',
}))
```
### Advanced usage - Change chaos probability
The probability of chaos can be configured in the input object param.
This parameter is a number value between 0 and 100.
```js
const {chaos} = require('express-chaos-middleware');
app.use(chaos({
probability: 50,
}))
```
### Advanced usage - Override max delay
The max slowdown delay can be configured in the input object param.
```js
const {chaos} = require('express-chaos-middleware');
app.use(chaos({
maxDelay: 1000,
}))
```
### Advanced usage - Use custom http error codes array
The http error codes array can be overridden in the input object param.
```js
const {chaos} = require('express-chaos-middleware');
app.use(chaos({
errCodes: [400, 500],
}))
```
### Advanced usage - Use custom feature list
The chaos feature list can be overridden in the input object param.
You can for example only use delay and http error codes with the following configuration
All rules are exported in the `Rules` object.
```js
const {chaos} = require('express-chaos-middleware');
app.use(chaos({
rules: [Rules.DELAY, Rules.HTTPERROR],
}))
```