judoscale-bull/README.md

Bull adapter for the Judoscale autoscaler

# Judoscale for Bull

Official [Judoscale](https://judoscale.com) adapter package for autoscaling Bull job queues.

## Set up your app for autoscaling

1. Install the judoscale-bull package:

```sh
npm install judoscale-bull --save
```

2. In your worker script, import and start the Judoscale reporter:

```javascript
// ESM
import { Judoscale } from 'judoscale-bull'

// CommonJS
const { Judoscale } = require('judoscale-bull')

// Initialize Judoscale with optional configuration
const judoscale = new Judoscale({
  redis_url: process.env.REDISCLOUD_URL, // defaults to process.env.REDIS_URL
})

// You can optionally pass a Redis config object or an ioredis instance
const judoscale = new Judoscale({
  redis: redisConfig,
})
```

3. If you want to scale your workers down to zero instances, you also need to install judoscale-bull in your web process so Judoscale knows when to scale them back up:

```javascript
// ESM
import { Judoscale, middleware as judoscaleMiddleware } from 'judoscale-express'
import 'judoscale-bull'

// CommonJS
const { Judoscale, middleware: judoscaleMiddleware } = require('judoscale-express')
require('judoscale-bull')

// Judoscale will be initialized for both Bull and Express/Fastify
const judoscale = new Judoscale({
  redis_url: process.env.REDISCLOUD_URL, // defaults to process.env.REDIS_URL
})
```

## Troubleshooting

Once installed, you should see something like this in your development log:

> [Judoscale] Reporter not started: JUDOSCALE_URL is not set

In your production app where you've installed Judoscale, you should see this in your logs:

> [Judoscale] Reporter starting, will report every 10 seconds

If you don't see either of these, ensure "judoscale-bull" is in your `Package.lock` file, and restart your app.

You can see more detailed (debug) logging by setting the environment variable `JUDOSCALE_LOG_LEVEL=debug` on your deployed application. Here's how you would do that on Heroku:

```
heroku config:set JUDOSCALE_LOG_LEVEL=debug
```

Reach out to help@judoscale.com if you run into any other problems.