Get inventory_item_id from Product Module

[Deroswent]

In Medusa V1 you can use ProductVariantInventoryService to get inventory_item_id from product variant_id. Like send product variant_id -> receive inventory_item_id associated with this product variant.

In Medusa v2 I can't find any methods to get inventory_item_id based on variant_id or product_id. It seems that such methods just doesn't exist.

How do I associate variant_id or product_id with inventory module and stock module? There are no methods to get any data about inventory or stock in Product Module.

[SalahAdDin]

Wait a minute, aren't those modules linked?

It is the main idea behind all the workflow!!!

[Deroswent]

You can't use Link because the two modules are already linked in the medusa core in LinkProductVariantInventoryItem.
You will just get the error:
error: Unable to merge GraphQL type “ProductVariant”: The field “inventory_items” is already defined with a different type. It is declared as “LinkProductVariantInventoryItem”, but you tried to override it with “InventoryItem”.

This is the main problem: you can't link modules because they are already linked. But you can't use variant_id -> inventory_item_id, because there is simply no method for that in any of the modules. Although there is such a method in v1. It looks like the developers just forgot about it.

I tried using a relation, I thought if these modules have a link- it might work, but that didn't work either.

If you have any ideas on how this can be done - please share.

[carlos-r-l-rodrigues]

You can use the query tool to get them. This is how you aggregate data from multiple modules.

await query.graph({
  entity: "product",
  fields: ["variants.inventory.*"],
})

[Deroswent]

Thank you for your response.

It looks very strange to use Query, considering that these two modules have a link in the core Medusa LinkProductVariantInventoryItem .

I haven't found a better option yet, it seems the developers just forgot to create some methods and now it's impossible to do it (I mean using Medusa methods).

I hope when the developers release an official guide on migration from v1 to v2, it will describe how to use some analog of ProductVariantInventoryService from v1 in the new version. This is quite an important method, they can't just remove it without explaining how to link this data together.

[carlos-r-l-rodrigues]

The query is the recommended approach to fetch data from multiple modules. Medusa 2.0 is modular, that means a module can be even an external 3rd party service, we can't just join tables as in v1.
But obviouly we can't prevent someone to just write a plain sql query joining everything because they know it just uses a single db instance. We just don't document nor recommend this approach