ASP.NET 6 HotChocolate SchemaStitching failure on remote schema fields

Question

I'm trying to change the example of SchemStitching on GitHub to use it from a products service instead of a gateway service.

The idea is to extend schema of the product and include information from inventory & reviews.

The changes I make in the products service:

add stitiching.graphql file with product type extension

extend type Product {
  inStock: Boolean
    @delegate(
      schema: "inventory",
      path: "inventoryInfo(upc: $fields:upc).isInStock")
  shippingEstimate: Int
    @delegate(
      schema: "inventory"
      path: "shippingEstimate(weight: $fields:weight price: $fields:price)")
  reviews: [Review] @delegate(schema: "reviews" path:"reviewsByProduct(upc: $fields:upc)")
}

Change Startup.cs to register remote schemas for inventory & reviews.

const string Inventory = "inventory";
const string Reviews = "reviews";

builder.Services.AddHttpClient(Inventory, 
    c => c.BaseAddress = new Uri("http://localhost:64309/graphql"));
builder.Services.AddHttpClient(Reviews, 
    c => c.BaseAddress = new Uri("http://localhost:64317/graphql"));

builder.Services
    .AddSingleton<ProductRepository>()
    .AddGraphQLServer()
    .AddQueryType<Query>()
    .AddRemoteSchema(Inventory, ignoreRootTypes: true)
    .AddRemoteSchema(Reviews, ignoreRootTypes: true)
    .AddTypeExtensionsFromFile("./Stitching.graphql");

When I run the application (running products, inventory, reviews services) in the hotchocolate playground running the following query

query {
  product(upc: 3) {
    name
    inStock
  }
}

I get back error for inStock

{
  "errors": [
    {
      "message": "Variable `__fields_upc` is required.",
      "extensions": {
        "code": "HC0018",
        "variable": "__fields_upc",
        "remote": {
          "message": "Variable `__fields_upc` is required.",
          "extensions": {
            "code": "HC0018",
            "variable": "__fields_upc"
          }
        },
        "schemaName": "inventory"
      }
    }
  ],
  "data": {
    "product": {
      "name": "Chair",
      "inStock": null
    }
  }
}

I can't figure out why upc field is not passed. It seems that validation fails on product service as I don't see any calls going out to inventory service.

Any clue what the issue is ?

I'm using ASP.NET 6 with

<PackageReference Include="HotChocolate.AspNetCore" Version="12.9.0" />
<PackageReference Include="HotChocolate.Stitching" Version="12.9.0" />

EDIT

It seems that $fields:upc is not getting resolved for inventory schema, because if I update the stitching schema with hard coded upc of 3

extend type Product {
  inStock: Boolean
    @delegate(
      schema: "inventory",
      path: "inventoryInfo(upc: 3).isInStock")
}

And query the data

query {
  product(upc: 3) {
    upc
    name
    inStock
  }
}

I get back results as expected

{
  "data": {
    "product": {
      "upc": 3,
      "name": "Chair",
      "inStock": true
    }
  }
}

You can move your edit in an answer and mark it as solution. — David, Jun 13 '22 at 21:43

score 0 · Answer 1 · answered Jun 13 '22 at 22:52

0

Also not? Your first query has not the 'upc' field what the error say.

query {
  product(upc: 3) {
    upc
    name
    inStock
  }
}

There is an example I found of graphql query similar to your scenario: https://chillicream.com/docs/hotchocolate/fetching-data/fetching-from-rest

answered Jun 13 '22 at 22:52

Sam

1,459
1
18
32

1

Thank you for suggestion @Sam. `$fields` refers to the product, which has `upc` field. See stitching documentation on `$fields` [here](https://chillicream.com/docs/hotchocolate/distributed-schema/schema-configuration/#field-reference-fields). Including `upc` makes no difference. – Mike Jun 14 '22 at 08:45

ASP.NET 6 HotChocolate SchemaStitching failure on remote schema fields

1 Answers1

Linked