PolarExpress Backend

This is the backend and infrastructure for the GraphPolaris marketplace.

Requirements

• A running instance of the GraphPolaris infrastructure, specifically:
  • RabbitMQ
  • MongoDB
  • Redis
  • MinIO
• Node.js 21 or later
• pnpm

Installation

Before starting the application, ensure the following services are running:

1. RabbitMQ
2. MongoDB
3. Redis
4. MinIO

Next, follow these steps:

1. Create a .env file and set the required environment variables to match your setup. For an example, see the sample.env file.
2. Install the dependencies using pnpm install.
3. Start the backend by running pnpm dev.

Seeding the Database

To seed the database, run:

pnpm seed

This will populate the database with randomly generated data.

If you want to set the seed of the generated data to get deterministic results, run:

pnpm seed -- <your seed here>

Scripts

To manage the application, use pnpm <script>, where <script> is one of the following:

• build - Compile the TypeScript code to JavaScript.
• dev - Start the development server with TypeScript and dotenv configuration.
• start - Start the production server using the compiled JavaScript code.
• seed - Seed the database with initial data.
• test - Run the test suite using Jest.
• load - Load additional modules using ts-node.
• lint - Run ESLint to lint the code.
• lint:fix - Automatically fix ESLint issues.
• format - Format the code using Prettier.
• prepare - Prepare the environment for Husky Git hooks (skipped in production).

API

The marketplace backend has two APIs: one for AMQP messages and one for HTTP requests. The HTTP API exists because a client has to be logged in to use the AMQP network.

HTTP Endpoints

/addons/get

POST /addons/get {
    category: "VISUALISATION" | "MACHINE_LEARNING" | undefined,
    page: number | undefined,
    searchTerm: string | undefined
}
=> { addons: [...], totalPages: number }

Get a list of addons.

• category: Filter by category.
• page: Page number of the page to get (default = 0).
• searchTerm: Optional search term to filter addons by name.

/addons/get-by-id

POST /addons/get-by-id {
    id: string
}
=> { addon: {...} }

Get an addon with the specified ID.

• id: the _id of the addon. This ID has been automatically generated by MongoDB when the addon was first loaded into the database.

/addons/get-readme

POST /addons/get-readme {
    id: string
}
=> { readme: "..." }

Get the contents of the README.md file belonging to the given addon.

• id: the _id of the addon. This ID has been automatically generated by MongoDB when the addon was first loaded into the database.

/store/...

This endpoint provides access to the MinIO data store.

AMQP Endpoints

Because AMQP is a publish-and-subscribe protocol, the concept of "endpoints" does not exist and is merely an abstraction on top of the AMQP routing. The client-updater-service provides one half of this abstraction, while the ts-amqp-socket package provides the other half. Communication with the client-updater-service is handled by broker.tsx in both the marketplace frontend and the GraphPolaris frontend.

Unlike other microservices, marketplace-backend does not use the subKey field to denote different endpoints. This is due to the limited expandability of this system, which requires modifications to the go-common repository. Instead, an action field is assumed to exist in the body object of the message. This field corresponds with the handler keys specified in the AmqpSocket.handle() calls. See the ts-amqp-socket package for more information.