42 lines
1.6 KiB
Plaintext
42 lines
1.6 KiB
Plaintext
---
|
||
description: "Learn what loaders are in Medusa. A loader is a script that runs when the Medusa backend starts."
|
||
---
|
||
|
||
import DocCard from '@theme/DocCard';
|
||
import Icons from '@theme/Icon';
|
||
|
||
# Loaders
|
||
|
||
In this document, you’ll learn what loaders are in Medusa.
|
||
|
||
## Overview
|
||
|
||
A loader is a script that runs when the Medusa backend starts. The Medusa backend uses loaders to initialize the database connection, load plugins, register resources in the dependency container, and more.
|
||
|
||
Loaders can be created within the Medusa backend codebase, in a plugin, or in a module to perform custom actions when the backend starts. The loader is created in a TypeScript or JavaScript file located in the `src/loaders` directory, then transpiled using the `build` command into the `dist/loaders` directory.
|
||
|
||
### Loader Examples
|
||
|
||
For example, the Redis Event Bus module uses a loader to establish a connection with Redis and log a message in the console.
|
||
|
||
Another example is the Algolia plugin, which uses a loader to update the index settings when the Medusa backend starts based on the plugin’s options.
|
||
|
||
Loaders can be used to access the dependency container and register custom resources in it.
|
||
|
||
Loaders can also be used to create [scheduled jobs](../scheduled-jobs/overview.mdx) that run at a specified interval of time.
|
||
|
||
---
|
||
|
||
## Custom Development
|
||
|
||
Developers can create a loader with the desired functionality directly within the Medusa Core, in a plugin, or in a module.
|
||
|
||
<DocCard item={{
|
||
type: 'link',
|
||
href: '/development/loaders/create',
|
||
label: 'Create a Loader',
|
||
customProps: {
|
||
icon: Icons['academic-cap-solid'],
|
||
description: 'Learn how to create a loader.'
|
||
}
|
||
}} /> |