# Configuration

Some times plugins may need to have custom configurations for each different usage. For example, a Google Analytics plugin will need a custom Tracking ID which will be different in each project.

## Usage

Plugins can be configured in the `config.plugins` object, where `config` is the object that is passed to the `boot` method.

So to configure the Google Analytics plugin create an object at `config.plugins[${slug}]` where `slug` is the plugin's slug.

To find out what configurations a plugin needs, please refer to the plugin documentation.

## Context

Plugin `initialize` functions get BlueRain context as second params.

## Accessing configurations inside Plugin

The plugin specific configurations are passed to the initialize method of the plugin class at system boot time.

```javascript
import { Plugin } from 'bluerain-os';

class GoogleAnalyticsPlugin extends Plugin {

    initialize(config, ctx) {
        // use config here
    }
}
```

## Example Usage

To use the Google Analytics plugin, first create a `plugins` file (or edit your existing one), and import the plugin. For this plugin we are use the custom key `'google-analytics'`.

```javascript
const googleAnalyticsPlugin = require('bluerain-plugin-google-analytics');

module.exports = [googleAnalyticsPlugin]
```

Now create a new `config.js` file (or edit your existing one) and put the following content in this file:

```javascript
module.exports = {
    plugins: {
        'google-analytics': {
            'tracking-id': 'GOOGLE_ANALYTICS_TRACKING_ID'
        }
    }
}
```

Note that we used the same custom key here to reference the plugin.

At last, boot your client with the plugin:

```javascript
import BR from '@blueeast/bluerain-os';

const config = require('./config');
const plugins = require('./plugins');

BR.boot({ config, plugins });
```


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