feat(medusa): Add inventory for variants (#2970)

* initial get-inventory impl

* add inventory management to create-variant

* update create-variant endpoint

* move if statement

* use middleware for module checking

* add endpoint to medusa-js

* export return type from get-inventory

* add jsdoc

* revert create variant

* rename variable

* initial setInventoryPattern for variant and product endpoints

* remove cache

* sort imports

* add sales channel info to inventory calculations

* add missing import

* remove promise.all from single promise

* update oas

* initial feedback

* checkout joinLevels from develop

* add variant middleware

* add comments

.changeset/spicy-singers-applaud.md

@@ -0,0 +1,5 @@
+---
+"@medusajs/medusa": patch
+---
+
+Feat(medusa): Add multi warehouse to create-variant and add list-inventory for variant endpoints

packages/medusa-js/src/resources/admin/variants.ts

@@ -1,9 +1,19 @@
-import { AdminGetVariantsParams, AdminVariantsListRes } from "@medusajs/medusa"
+import {
+  AdminGetVariantsVariantInventoryRes,
+  AdminGetVariantsParams,
+  AdminVariantsListRes,
+} from "@medusajs/medusa"
 import qs from "qs"
 import { ResponsePromise } from "../.."
 import BaseResource from "../base"
 
 class AdminVariantsResource extends BaseResource {
+  /**
+   * List product variants
+   * @param query Query to filter variants by
+   * @param customHeaders custom headers
+   * @returns A list of variants satisfying the criteria of the query
+   */
   list(
     query?: AdminGetVariantsParams,
     customHeaders: Record<string, any> = {}
@@ -17,6 +27,21 @@ class AdminVariantsResource extends BaseResource {
 
     return this.client.request("GET", path, undefined, {}, customHeaders)
   }
+
+  /**
+   *
+   * @param variantId id of the variant to fetch inventory for
+   * @param customHeaders custom headers
+   * @returns
+   */
+  getInventory(
+    variantId: string,
+    customHeaders: Record<string, any> = {}
+  ): ResponsePromise<AdminGetVariantsVariantInventoryRes> {
+    const path = `/admin/variants/${variantId}/inventory`
+
+    return this.client.request("GET", path, undefined, {}, customHeaders)
+  }
 }
 
 export default AdminVariantsResource

packages/medusa/src/api/middlewares/publishable-api-key/validate-variant-sales-channel-association.ts

@@ -0,0 +1,48 @@
+import { NextFunction, Request, Response } from "express"
+
+import PublishableApiKeyService from "../../../services/publishable-api-key"
+import { ProductService, ProductVariantService } from "../../../services"
+
+/**
+ * The middleware check if requested product is assigned to a SC associated with PK in the header.
+ *
+ * @param req - request object
+ * @param res - response object
+ * @param next - next middleware call
+ */
+async function validateProductVariantSalesChannelAssociation(
+  req: Request,
+  res: Response,
+  next: NextFunction
+) {
+  const pubKey = req.get("x-publishable-api-key")
+
+  if (pubKey) {
+    const productVariantService: ProductVariantService = req.scope.resolve(
+      "productVariantService"
+    )
+    const publishableKeyService: PublishableApiKeyService = req.scope.resolve(
+      "publishableApiKeyService"
+    )
+
+    const { sales_channel_id: salesChannelIds } =
+      await publishableKeyService.getResourceScopes(pubKey)
+
+    if (
+      salesChannelIds.length &&
+      !(await productVariantService.isVariantInSalesChannels(
+        req.params.id,
+        salesChannelIds
+      ))
+    ) {
+      req.errors = req.errors ?? []
+      req.errors.push(
+        `Variant with id: ${req.params.id} is not associated with sales channels defined by the Publishable API Key passed in the header of the request.`
+      )
+    }
+  }
+
+  next()
+}
+
+export { validateProductVariantSalesChannelAssociation }

packages/medusa/src/api/routes/admin/variants/get-inventory.ts

@@ -0,0 +1,180 @@
+import {
+  InventoryItemDTO,
+  InventoryLevelDTO,
+} from "../../../../types/inventory"
+import ProductVariantInventoryService from "../../../../services/product-variant-inventory"
+import {
+  SalesChannelLocationService,
+  SalesChannelService,
+} from "../../../../services"
+import { SalesChannel } from "../../../../models"
+import { IInventoryService } from "../../../../interfaces"
+import ProductVariantService from "../../../../services/product-variant"
+import { joinLevels } from "../inventory-items/utils/join-levels"
+
+/**
+ * @oas [get] /variants/{id}/inventory
+ * operationId: "GetVariantsVariantInventory"
+ * summary: "Get inventory of Variant."
+ * description: "Returns the available inventory of a Variant."
+ * x-authenticated: true
+ * parameters:
+ *   - (path) id {string} The Product Variant id to get inventory for.
+ * x-codeSamples:
+ *   - lang: JavaScript
+ *     label: JS Client
+ *     source: |
+ *       import Medusa from "@medusajs/medusa-js"
+ *       const medusa = new Medusa({ baseUrl: MEDUSA_BACKEND_URL, maxRetries: 3 })
+ *       // must be previously logged in or use api token
+ *       medusa.admin.variants.list()
+ *         .then(({ variants, limit, offset, count }) => {
+ *           console.log(variants.length)
+ *         })
+ *   - lang: Shell
+ *     label: cURL
+ *     source: |
+ *       curl --location --request GET 'https://medusa-url.com/admin/variants' \
+ *       --header 'Authorization: Bearer {api_token}'
+ * security:
+ *   - api_token: []
+ *   - cookie_auth: []
+ * tags:
+ *   - Product Variant
+ * responses:
+ *   200:
+ *     description: OK
+ *     content:
+ *       application/json:
+ *         schema:
+ *           type: object
+ *           properties:
+ *             variant:
+ *               type: object
+ *               $ref: "#/components/schemas/AdminGetVariantsVariantInventoryRes"
+ *   "400":
+ *     $ref: "#/components/responses/400_error"
+ *   "401":
+ *     $ref: "#/components/responses/unauthorized"
+ *   "404":
+ *     $ref: "#/components/responses/not_found_error"
+ *   "409":
+ *     $ref: "#/components/responses/invalid_state_error"
+ *   "422":
+ *     $ref: "#/components/responses/invalid_request_error"
+ *   "500":
+ *     $ref: "#/components/responses/500_error"
+ */
+export default async (req, res) => {
+  const { id } = req.params
+
+  const inventoryService: IInventoryService =
+    req.scope.resolve("inventoryService")
+  const channelLocationService: SalesChannelLocationService = req.scope.resolve(
+    "salesChannelLocationService"
+  )
+  const channelService: SalesChannelService = req.scope.resolve(
+    "salesChannelService"
+  )
+  const productVariantInventoryService: ProductVariantInventoryService =
+    req.scope.resolve("productVariantInventoryService")
+
+  const variantService: ProductVariantService = req.scope.resolve(
+    "productVariantService"
+  )
+
+  const variant = await variantService.retrieve(id, { select: ["id"] })
+
+  const responseVariant: AdminGetVariantsVariantInventoryRes = {
+    id: variant.id,
+    inventory: [],
+    sales_channel_availability: [],
+  }
+
+  const [rawChannels] = await channelService.listAndCount({})
+  const channels: SalesChannelDTO[] = await Promise.all(
+    rawChannels.map(async (channel) => {
+      const locations = await channelLocationService.listLocations(channel.id)
+      return {
+        ...channel,
+        locations,
+      }
+    })
+  )
+
+  const inventory =
+    await productVariantInventoryService.listInventoryItemsByVariant(variant.id)
+  responseVariant.inventory = await joinLevels(inventory, [], inventoryService)
+
+  // TODO: adjust for required quantity
+  if (inventory.length) {
+    responseVariant.sales_channel_availability = await Promise.all(
+      channels.map(async (channel) => {
+        if (!channel.locations.length) {
+          return {
+            channel_name: channel.name as string,
+            channel_id: channel.id as string,
+            available_quantity: 0,
+          }
+        }
+
+        const quantity = await inventoryService.retrieveAvailableQuantity(
+          inventory[0].id,
+          channel.locations
+        )
+
+        return {
+          channel_name: channel.name as string,
+          channel_id: channel.id as string,
+          available_quantity: quantity,
+        }
+      })
+    )
+  }
+
+  res.json({
+    variant: responseVariant,
+  })
+}
+
+type SalesChannelDTO = Omit<SalesChannel, "beforeInsert"> & {
+  locations: string[]
+}
+
+type ResponseInventoryItem = Partial<InventoryItemDTO> & {
+  location_levels?: InventoryLevelDTO[]
+}
+
+/**
+ * @schema AdminGetVariantsVariantInventoryRes
+ * type: object
+ * properties:
+ *   id:
+ *     description: the id of the variant
+ *     type: string
+ *   inventory:
+ *     description: the stock location address ID
+ *     type: string
+ *   sales_channel_availability:
+ *     type: object
+ *     description: An optional key-value map with additional details
+ *     properties:
+ *       channel_name:
+ *         description: Sales channel name
+ *         type: string
+ *       channel_id:
+ *         description: Sales channel id
+ *         type: string
+ *       available_quantity:
+ *         description: Available quantity in sales channel
+ *         type: number
+ */
+export type AdminGetVariantsVariantInventoryRes = {
+  id: string
+  inventory: ResponseInventoryItem[]
+  sales_channel_availability: {
+    channel_name: string
+    channel_id: string
+    available_quantity: number
+  }[]
+}

packages/medusa/src/api/routes/admin/variants/index.ts

@@ -4,6 +4,7 @@ import { ProductVariant } from "../../../../models/product-variant"
 import { PaginatedResponse } from "../../../../types/common"
 import { PricedVariant } from "../../../../types/pricing"
 import middlewares, { transformQuery } from "../../../middlewares"
+import { checkRegisteredModules } from "../../../middlewares/check-registered-modules"
 import { AdminGetVariantsParams } from "./list-variants"
 
 const route = Router()
@@ -21,6 +22,15 @@ export default (app) => {
     middlewares.wrap(require("./list-variants").default)
   )
 
+  route.get(
+    "/:id/inventory",
+    checkRegisteredModules({
+      inventoryService:
+        "Inventory is not enabled. Please add an Inventory module to enable this functionality.",
+    }),
+    middlewares.wrap(require("./get-inventory").default)
+  )
+
   return app
 }
 
@@ -72,3 +82,4 @@ export type AdminVariantsListRes = PaginatedResponse & {
 }
 
 export * from "./list-variants"
+export * from "./get-inventory"

packages/medusa/src/api/routes/store/products/get-product.ts

@@ -1,11 +1,15 @@
+import { IsOptional, IsString } from "class-validator"
 import { defaultStoreProductsRelations } from "."
+import PublishableAPIKeysFeatureFlag from "../../../../loaders/feature-flags/publishable-api-keys"
 import {
   CartService,
   PricingService,
   ProductService,
+  ProductVariantInventoryService,
   RegionService,
 } from "../../../../services"
 import { PriceSelectionParams } from "../../../../types/price-selection"
+import { FlagRouter } from "../../../../utils/flag-router"
 import { validator } from "../../../../utils/validator"
 
 /**
@@ -15,6 +19,7 @@ import { validator } from "../../../../utils/validator"
  * description: "Retrieves a Product."
  * parameters:
  *   - (path) id=* {string} The id of the Product.
+ *   - (query) sales_channel_id {string} The sales channel used when fetching the product.
  *   - (query) cart_id {string} The ID of the customer's cart.
  *   - (query) region_id {string} The ID of the region the customer is using. This is helpful to ensure correct prices are retrieved for a region.
  *   - in: query
@@ -71,6 +76,8 @@ export default async (req, res) => {
 
   const customer_id = req.user?.customer_id
 
+  const productVariantInventoryService: ProductVariantInventoryService =
+    req.scope.resolve("productVariantInventoryService")
   const productService: ProductService = req.scope.resolve("productService")
   const pricingService: PricingService = req.scope.resolve("pricingService")
   const cartService: CartService = req.scope.resolve("cartService")
@@ -79,6 +86,14 @@ export default async (req, res) => {
     relations: defaultStoreProductsRelations,
   })
 
+  let sales_channel_id = validated.sales_channel_id
+  const featureFlagRouter: FlagRouter = req.scope.resolve("featureFlagRouter")
+  if (featureFlagRouter.isFeatureEnabled(PublishableAPIKeysFeatureFlag.key)) {
+    if (req.publishableApiKeyScopes?.sales_channel_id.length === 1) {
+      sales_channel_id = req.publishableApiKeyScopes.sales_channel_id[0]
+    }
+  }
+
   let regionId = validated.region_id
   let currencyCode = validated.currency_code
   if (validated.cart_id) {
@@ -92,15 +107,27 @@ export default async (req, res) => {
     currencyCode = region.currency_code
   }
 
-  const [product] = await pricingService.setProductPrices([rawProduct], {
-    cart_id: validated.cart_id,
-    customer_id: customer_id,
-    region_id: regionId,
-    currency_code: currencyCode,
-    include_discount_prices: true,
-  })
+  const pricedProductArray = await pricingService.setProductPrices(
+    [rawProduct],
+    {
+      cart_id: validated.cart_id,
+      customer_id: customer_id,
+      region_id: regionId,
+      currency_code: currencyCode,
+      include_discount_prices: true,
+    }
+  )
+
+  const [product] = await productVariantInventoryService.setProductAvailability(
+    pricedProductArray,
+    sales_channel_id
+  )
 
   res.json({ product })
 }
 
-export class StoreGetProductsProductParams extends PriceSelectionParams {}
+export class StoreGetProductsProductParams extends PriceSelectionParams {
+  @IsString()
+  @IsOptional()
+  sales_channel_id?: string
+}

packages/medusa/src/api/routes/store/products/list-products.ts

@@ -10,6 +10,7 @@ import {
 import {
   CartService,
   ProductService,
+  ProductVariantInventoryService,
   RegionService,
 } from "../../../../services"
 import SalesChannelFeatureFlag from "../../../../loaders/feature-flags/sales-channels"
@@ -171,6 +172,8 @@ import PublishableAPIKeysFeatureFlag from "../../../../loaders/feature-flags/pub
  */
 export default async (req, res) => {
   const productService: ProductService = req.scope.resolve("productService")
+  const productVariantInventoryService: ProductVariantInventoryService =
+    req.scope.resolve("productVariantInventoryService")
   const pricingService: PricingService = req.scope.resolve("pricingService")
   const cartService: CartService = req.scope.resolve("cartService")
   const regionService: RegionService = req.scope.resolve("regionService")
@@ -214,7 +217,7 @@ export default async (req, res) => {
     currencyCode = region.currency_code
   }
 
-  const products = await pricingService.setProductPrices(rawProducts, {
+  const pricedProducts = await pricingService.setProductPrices(rawProducts, {
     cart_id: cart_id,
     region_id: regionId,
     currency_code: currencyCode,
@@ -222,6 +225,11 @@ export default async (req, res) => {
     include_discount_prices: true,
   })
 
+  const products = await productVariantInventoryService.setProductAvailability(
+    pricedProducts,
+    filterableFields.sales_channel_id
+  )
+
   res.json({
     products,
     count,

packages/medusa/src/api/routes/store/variants/get-variant.ts

@@ -1,6 +1,7 @@
 import {
   CartService,
   PricingService,
+  ProductVariantInventoryService,
   ProductVariantService,
   RegionService,
 } from "../../../../services"
@@ -8,6 +9,9 @@ import {
 import { PriceSelectionParams } from "../../../../types/price-selection"
 import { defaultStoreVariantRelations } from "."
 import { validator } from "../../../../utils/validator"
+import { IsOptional, IsString } from "class-validator"
+import PublishableAPIKeysFeatureFlag from "../../../../loaders/feature-flags/publishable-api-keys"
+import { FlagRouter } from "../../../../utils/flag-router"
 
 /**
  * @oas [get] /variants/{variant_id}
@@ -17,6 +21,7 @@ import { validator } from "../../../../utils/validator"
  * parameters:
  *   - (path) variant_id=* {string} The id of the Product Variant.
  *   - (query) cart_id {string} The id of the Cart to set prices based on.
+ *   - (query) sales_channel_id {string} A sales channel id for result configuration.
  *   - (query) region_id {string} The id of the Region to set prices based on.
  *   - in: query
  *     name: currency_code
@@ -65,6 +70,8 @@ export default async (req, res) => {
     "productVariantService"
   )
   const pricingService: PricingService = req.scope.resolve("pricingService")
+  const productVariantInventoryService: ProductVariantInventoryService =
+    req.scope.resolve("productVariantInventoryService")
   const cartService: CartService = req.scope.resolve("cartService")
   const regionService: RegionService = req.scope.resolve("regionService")
 
@@ -74,6 +81,14 @@ export default async (req, res) => {
     relations: defaultStoreVariantRelations,
   })
 
+  let sales_channel_id = validated.sales_channel_id
+  const featureFlagRouter: FlagRouter = req.scope.resolve("featureFlagRouter")
+  if (featureFlagRouter.isFeatureEnabled(PublishableAPIKeysFeatureFlag.key)) {
+    if (req.publishableApiKeyScopes?.sales_channel_id.length === 1) {
+      sales_channel_id = req.publishableApiKeyScopes.sales_channel_id[0]
+    }
+  }
+
   let regionId = validated.region_id
   let currencyCode = validated.currency_code
   if (validated.cart_id) {
@@ -87,7 +102,7 @@ export default async (req, res) => {
     currencyCode = region.currency_code
   }
 
-  const [variant] = await pricingService.setVariantPrices([rawVariant], {
+  const variantRes = await pricingService.setVariantPrices([rawVariant], {
     cart_id: validated.cart_id,
     customer_id: customer_id,
     region_id: regionId,
@@ -95,7 +110,16 @@ export default async (req, res) => {
     include_discount_prices: true,
   })
 
+  const [variant] = await productVariantInventoryService.setVariantAvailability(
+    variantRes,
+    sales_channel_id
+  )
+
   res.json({ variant })
 }
 
-export class StoreGetVariantsVariantParams extends PriceSelectionParams {}
+export class StoreGetVariantsVariantParams extends PriceSelectionParams {
+  @IsString()
+  @IsOptional()
+  sales_channel_id?: string
+}

packages/medusa/src/api/routes/store/variants/index.ts

@@ -1,12 +1,26 @@
 import { ProductVariant } from "../../../../"
-import { Router } from "express"
+import { RequestHandler, Router } from "express"
 import middlewares from "../../../middlewares"
+import { featureFlagRouter } from "../../../../loaders/feature-flags"
+import PublishableAPIKeysFeatureFlag from "../../../../loaders/feature-flags/publishable-api-keys"
+import { extendRequestParams } from "../../../middlewares/publishable-api-key/extend-request-params"
+import { validateSalesChannelParam } from "../../../middlewares/publishable-api-key/validate-sales-channel-param"
+import { validateProductVariantSalesChannelAssociation } from "../../../middlewares/publishable-api-key/validate-variant-sales-channel-association"
 
 const route = Router()
 
 export default (app) => {
   app.use("/variants", route)
 
+  if (featureFlagRouter.isFeatureEnabled(PublishableAPIKeysFeatureFlag.key)) {
+    route.use(
+      "/",
+      extendRequestParams as unknown as RequestHandler,
+      validateSalesChannelParam as unknown as RequestHandler
+    )
+    route.use("/:id", validateProductVariantSalesChannelAssociation)
+  }
+
   route.get("/", middlewares.wrap(require("./list-variants").default))
   route.get("/:id", middlewares.wrap(require("./get-variant").default))
 

packages/medusa/src/api/routes/store/variants/list-variants.ts

@@ -2,6 +2,7 @@ import { IsInt, IsOptional, IsString } from "class-validator"
 import {
   CartService,
   PricingService,
+  ProductVariantInventoryService,
   ProductVariantService,
   RegionService,
 } from "../../../../services"
@@ -14,6 +15,8 @@ import { PriceSelectionParams } from "../../../../types/price-selection"
 import { FilterableProductVariantProps } from "../../../../types/product-variant"
 import { validator } from "../../../../utils/validator"
 import { IsType } from "../../../../utils/validators/is-type"
+import PublishableAPIKeysFeatureFlag from "../../../../loaders/feature-flags/publishable-api-keys"
+import { FlagRouter } from "../../../../utils/flag-router"
 
 /**
  * @oas [get] /variants
@@ -22,6 +25,7 @@ import { IsType } from "../../../../utils/validators/is-type"
  * description: "Retrieves a list of Product Variants"
  * parameters:
  *   - (query) ids {string} A comma separated list of Product Variant ids to filter by.
+ *   - (query) sales_channel_id {string} A sales channel id for result configuration.
  *   - (query) expand {string} A comma separated list of Product Variant relations to load.
  *   - (query) offset=0 {number} How many product variants to skip in the result.
  *   - (query) limit=100 {number} Maximum number of Product Variants to return.
@@ -124,11 +128,21 @@ export default async (req, res) => {
     filterableFields.id = validated.ids.split(",")
   }
 
+  let sales_channel_id = validated.sales_channel_id
+  const featureFlagRouter: FlagRouter = req.scope.resolve("featureFlagRouter")
+  if (featureFlagRouter.isFeatureEnabled(PublishableAPIKeysFeatureFlag.key)) {
+    if (req.publishableApiKeyScopes?.sales_channel_id.length === 1) {
+      sales_channel_id = req.publishableApiKeyScopes.sales_channel_id[0]
+    }
+  }
+
   const pricingService: PricingService = req.scope.resolve("pricingService")
   const variantService: ProductVariantService = req.scope.resolve(
     "productVariantService"
   )
   const cartService: CartService = req.scope.resolve("cartService")
+  const productVariantInventoryService: ProductVariantInventoryService =
+    req.scope.resolve("productVariantInventoryService")
   const regionService: RegionService = req.scope.resolve("regionService")
 
   const rawVariants = await variantService.list(filterableFields, listConfig)
@@ -146,7 +160,7 @@ export default async (req, res) => {
     currencyCode = region.currency_code
   }
 
-  const variants = await pricingService.setVariantPrices(rawVariants, {
+  const pricedVariants = await pricingService.setVariantPrices(rawVariants, {
     cart_id: validated.cart_id,
     region_id: regionId,
     currency_code: currencyCode,
@@ -154,6 +168,11 @@ export default async (req, res) => {
     include_discount_prices: true,
   })
 
+  const variants = await productVariantInventoryService.setVariantAvailability(
+    pricedVariants,
+    sales_channel_id
+  )
+
   res.json({ variants })
 }
 
@@ -176,6 +195,10 @@ export class StoreGetVariantsParams extends PriceSelectionParams {
   @IsString()
   ids?: string
 
+  @IsOptional()
+  @IsString()
+  sales_channel_id?: string
+
   @IsOptional()
   @IsType([String, [String]])
   id?: string | string[]

packages/medusa/src/services/__mocks__/product-variant-inventory.js

@@ -22,6 +22,16 @@ export const ProductVariantInventoryServiceMock = {
   validateInventoryAtLocation: jest
     .fn()
     .mockImplementation((items, locationId) => {}),
+  setVariantAvailability: jest
+    .fn()
+    .mockImplementation((variants, salesChannelId) => {
+      return variants
+    }),
+  setProductAvailability: jest
+    .fn()
+    .mockImplementation((products, salesChannelId) => {
+      return products
+    }),
 }
 
 const mock = jest.fn().mockImplementation(() => {

packages/medusa/src/services/product-variant-inventory.ts

@@ -1,22 +1,29 @@
 import { isDefined, MedusaError } from "medusa-core-utils"
 import { EntityManager, In } from "typeorm"
 import {
-  IStockLocationService,
   IInventoryService,
+  IStockLocationService,
   TransactionBaseService,
 } from "../interfaces"
+import { LineItem, Product, ProductVariant } from "../models"
 import { ProductVariantInventoryItem } from "../models/product-variant-inventory-item"
-import { ProductVariantService, SalesChannelLocationService } from "./"
 import {
   InventoryItemDTO,
   ReservationItemDTO,
   ReserveQuantityContext,
 } from "../types/inventory"
-import { LineItem, ProductVariant } from "../models"
+import { PricedProduct, PricedVariant } from "../types/pricing"
+import {
+  CacheService,
+  ProductVariantService,
+  SalesChannelInventoryService,
+  SalesChannelLocationService,
+} from "./"
 
 type InjectedDependencies = {
   manager: EntityManager
   salesChannelLocationService: SalesChannelLocationService
+  salesChannelInventoryService: SalesChannelInventoryService
   productVariantService: ProductVariantService
   stockLocationService: IStockLocationService
   inventoryService: IInventoryService
@@ -27,14 +34,17 @@ class ProductVariantInventoryService extends TransactionBaseService {
   protected transactionManager_: EntityManager | undefined
 
   protected readonly salesChannelLocationService_: SalesChannelLocationService
+  protected readonly salesChannelInventoryService_: SalesChannelInventoryService
   protected readonly productVariantService_: ProductVariantService
   protected readonly stockLocationService_: IStockLocationService
   protected readonly inventoryService_: IInventoryService
+  protected readonly cacheService_: CacheService
 
   constructor({
     manager,
     stockLocationService,
     salesChannelLocationService,
+    salesChannelInventoryService,
     productVariantService,
     inventoryService,
   }: InjectedDependencies) {
@@ -43,6 +53,7 @@ class ProductVariantInventoryService extends TransactionBaseService {
 
     this.manager_ = manager
     this.salesChannelLocationService_ = salesChannelLocationService
+    this.salesChannelInventoryService_ = salesChannelInventoryService
     this.stockLocationService_ = stockLocationService
     this.productVariantService_ = productVariantService
     this.inventoryService_ = inventoryService
@@ -598,6 +609,74 @@ class ProductVariantInventoryService extends TransactionBaseService {
       )
     }
   }
+
+  async setVariantAvailability(
+    variants: ProductVariant[] | PricedVariant[],
+    salesChannelId: string | undefined
+  ): Promise<ProductVariant[] | PricedVariant[]> {
+    if (!this.inventoryService_) {
+      return variants
+    }
+
+    return await Promise.all(
+      variants.map(async (variant) => {
+        if (!variant.id) {
+          return variant
+        }
+
+        if (!salesChannelId) {
+          delete variant.inventory_quantity
+          return variant
+        }
+
+        // first get all inventory items required for a variant
+        const variantInventory = await this.listByVariant(variant.id)
+
+        // the inventory quantity of the variant should be equal to the inventory
+        // item with the smallest stock, adjusted for quantity required to fulfill
+        // the given variant
+        variant.inventory_quantity = Math.min(
+          ...(await Promise.all(
+            variantInventory.map(async (variantInventory) => {
+              // get the total available quantity for the given sales channel
+              // divided by the required quantity to account for how many of the
+              // variant we can fulfill at the current time. Take the minimum we
+              // can fulfill and set that as quantity
+              return (
+                // eslint-disable-next-line max-len
+                (await this.salesChannelInventoryService_.retrieveAvailableItemQuantity(
+                  salesChannelId,
+                  variantInventory.inventory_item_id
+                )) / variantInventory.required_quantity
+              )
+            })
+          ))
+        )
+
+        return variant
+      })
+    )
+  }
+
+  async setProductAvailability(
+    products: (Product | PricedProduct)[],
+    salesChannelId: string | undefined
+  ): Promise<(Product | PricedProduct)[]> {
+    return await Promise.all(
+      products.map(async (product) => {
+        if (!product.variants || product.variants.length === 0) {
+          return product
+        }
+
+        product.variants = await this.setVariantAvailability(
+          product.variants,
+          salesChannelId
+        )
+
+        return product
+      })
+    )
+  }
 }
 
 export default ProductVariantInventoryService

packages/medusa/src/services/product-variant.ts

@@ -47,6 +47,7 @@ class ProductVariantService extends TransactionBaseService {
   protected readonly regionService_: RegionService
   protected readonly priceSelectionStrategy_: IPriceSelectionStrategy
   protected readonly moneyAmountRepository_: typeof MoneyAmountRepository
+  // eslint-disable-next-line max-len
   protected readonly productOptionValueRepository_: typeof ProductOptionValueRepository
   protected readonly cartRepository_: typeof CartRepository
 
@@ -61,6 +62,7 @@ class ProductVariantService extends TransactionBaseService {
     cartRepository,
     priceSelectionStrategy,
   }) {
+    // eslint-disable-next-line prefer-rest-params
     super(arguments[0])
 
     this.manager_ = manager
@@ -675,6 +677,28 @@ class ProductVariantService extends TransactionBaseService {
     })
   }
 
+  /**
+   * Check if the variant is assigned to at least one of the provided sales channels.
+   *
+   * @param id - product variant id
+   * @param salesChannelIds - an array of sales channel ids
+   */
+  async isVariantInSalesChannels(
+    id: string,
+    salesChannelIds: string[]
+  ): Promise<boolean> {
+    const variant = await this.retrieve(id, {
+      relations: ["product", "product.sales_channels"],
+    })
+
+    // TODO: reimplement this to use db level check
+    const productsSalesChannels = variant.product.sales_channels.map(
+      (channel) => channel.id
+    )
+
+    return productsSalesChannels.some((id) => salesChannelIds.includes(id))
+  }
+
   /**
    * Creates a query object to be used for list queries.
    * @param selector - the selector to create the query from