Incorrect documentation, how to do it correctly?

[AlexeyRaga]

The documentation for combining multiple sources has this code:

  extend type Book {
    author: authors_v1_Author @resolveTo(
      sourceName: "Authors" # Which source does the target field belong to?
      sourceTypeName: "Query", # Which root type does the target field belong to?
      sourceFieldName: "authors_v1_AuthorsService_GetAuthor", # What is the source field name?
      requiredSelectionSet: "{ authorId }",
      sourceArgs: # What args does this need to take? {
        "input.id": "{root.authorId}"
      }
    )
  }

It has missing commas and misplaced comments, but even after fixing those I cannot figure out how to make it work.

I now have it as

additionalTypeDefs: |
  extend type Book {
    author: authors_v1_Author @resolveTo(
      sourceName: "Authors",
      sourceTypeName: "Query",
      sourceFieldName: "authors_v1_AuthorsService_GetAuthor",
      requiredSelectionSet: "{ authorId }",
      sourceArgs: {
        "input.id": "{root.authorId}"
      }
    )
  }

And here is the error message that I get:

Mesh AggregateError: Failed to find any GraphQL type definitions in: extend type Book {
  author: authors_v1_Author @resolveTo(
    sourceName: "Authors",
    sourceTypeName: "Query",
    sourceFieldName: "authors_v1_AuthorsService_GetAuthor",
    requiredSelectionSet: "{ authorId }",
    sourceArgs: {
      "input.id": "{root.authorId}"
    }
  )
}
;
 - ENAMETOOLONG: name too long, stat '/service/extend type Book {
  author: authors_v1_Author @resolveTo(
    sourceName: "Authors",
    sourceTypeName: "Query",
    sourceFieldName: "authors_v1_AuthorsService_GetAuthor",
    requiredSelectionSet: "{ authorId }",
    sourceArgs: {
      "input.id": "{root.authorId}"
    }
  )
}

Using additionalResolvers in yaml works, but I still want to make it work in this more explicit way.

I am using the following versions of packages:

  "dependencies": {
    "@graphql-mesh/cli": "^0.82.35",
    "@graphql-mesh/graphql": "^0.93.1",
    "@graphql-mesh/openapi": "^0.93.1",
    "@graphql-mesh/grpc": "^0.93.2",
    "@graphql-mesh/runtime": "^0.93.2",
    "@graphql-mesh/transform-filter-schema": "^0.93.2",
    "@graphql-mesh/transform-rename": "^0.93.1",
    "graphql": "^16.3.0"
  }

Can anyone please advise on how to make it work?

[AlexeyRaga]

I figured that the problem is most likely in this block:

      sourceArgs: {
        "input.id": "{root.authorId}"
      }

I tried to write it differently, for example

      sourceArgs: {
        input: { id: "{root.authorId}" }
      }

This one starts properly, but then I get the following error when querying:

"message": "additionalResolver.sourceArgs[argPath].toString is not a function"

and some other variations but it didn't help.

[sraza-onshape]

Hi @AlexeyRaga, I ran into a similar issue. This is just my best guess, but I believe the root cause is that (at least for the version of the library you/I are using), the @resolve() function is no longer supposed to be used under the additionalTypeDefs property in .meshrc.yaml file.

I believe what you're supposed to do now is use the additionalResolvers property in the file, to separate concerns from the additional type fields. This is what I have in mine, to give you an idea:

# .meshrc.yaml
...
additionalTypeDefs: |
  ...
  extend type Book {
    author: authors_v1_Author
  }
additionalResolvers:
  ... 
  - targetTypeName: Book
    targetFieldName: author
    sourceName: Authors # Which source does the target field belong to?
    sourceTypeName: Query # Which root type does the target field belong to?
    sourceFieldName: authors_v1_AuthorsService_GetAuthor # What is the source field name?
    requiredSelectionSet:
      |
      {
        authorId
      }
    sourceArgs: # What args does this need to take?
      input.id: "{root.authorId}"

The full source code is available here so you can look. I think the main point is just to move the logic from @resolve() under additionalResolvers.

[ardatan]

the @resolve() function is no longer supposed to be used under the additionalTypeDefs property in .meshrc.yaml file.

This is not true, actually :)

@resolveTo directive is still the recommended way of extending the schema. The code in this example has recently been updated. Please let us know if the issue still persists.