How to retrieve a product object associated with a product_id in backend folder

[open marsh]

I want to develop a custom functionality that requires to get the product associated with the product id in one of the file in the backend folder.

[grand fiber]

In what file?

https://docs.medusajs.com/development/fundamentals/dependency-injection#loading-resources

the service is called productService

Then you use retrieve on the productService to get the product by id

https://docs.medusajs.com/development/services/overview

https://docs.medusajs.com/references/services/classes/ProductService#retrieve

[open marsh]

I want to customise the calculateVariantPrice Method so I need this there