Gqlgen: Apollo Federation: 422: Unprocessable Entity when no entity defined

[aaad]

What happened?

There is a service which only contains a mutation which has only input types defined:

extend type Mutation {
  addSurveyResult(result: SurveyResult!): ID
}

input SurveyResultTuple {
     key: String
     value: String
}

input SurveyResult {
  userId: ID!

  type: String!

  elements: [SurveyResultTuple!]!
}

when I try to federate the service by a gateway the following errors occure:

Service:

unknown field "_service"

goroutine 9 [running]:
runtime/debug.Stack(0x1, 0x0, 0x0)
/usr/local/go/src/runtime/debug/stack.go:24 +0x9d
runtime/debug.PrintStack()
/usr/local/go/src/runtime/debug/stack.go:16 +0x22
github.com/99designs/gqlgen/graphql.DefaultRecover(0xc0c740, 0xc0002c8690, 0x9fe620, 0xc0001b8de0, 0x44900f, 0x18)
/home/simon/go/pkg/mod/github.com/99designs/[email protected]/graphql/recovery.go:16 +0xa7
github.com/99designs/gqlgen/graphql/handler.(Server).ServeHTTP.func1(0xc0000d5e40, 0xc00013fbd0, 0xc0ae40, 0xc0002922a0)
/home/simon/go/pkg/mod/github.com/99designs/[email protected]/graphql/handler/server.go:124 +0xa7
panic(0x9fe620, 0xc0001b8de0)
/usr/local/go/src/runtime/panic.go:679 +0x1b2
recommender-survey-archive/cmd/graph/generated.(executionContext)._Query(0xc0001b8da0, 0xc0c740, 0xc0002c8ff0, 0xc0001b8b40, 0x1, 0x1, 0x40dcc6, 0xc0002c8fc0)
/home/simon/go/src/recommender-survey-archive/cmd/graph/generated/generated.go:1527 +0x6b4
recommender-survey-archive/cmd/graph/generated.(executableSchema).Exec.func1(0xc0c740, 0xc0002c8fc0, 0x10)
/home/simon/go/src/recommender-survey-archive/cmd/graph/generated/generated.go:99 +0x7b
github.com/99designs/gqlgen/graphql/handler.executor.DispatchOperation.func1.1.1(0xc0c740, 0xc0002c8fc0, 0xc0001b8db0)
/home/simon/go/pkg/mod/github.com/99designs/[email protected]/graphql/handler/executor.go:100 +0x43
github.com/99designs/gqlgen/graphql/handler.newExecutor.func2(0xc0c740, 0xc0002c8fc0, 0xc0001b8db0, 0xbeec60)
/home/simon/go/pkg/mod/github.com/99designs/[email protected]/graphql/handler/executor.go:33 +0x3a
github.com/99designs/gqlgen/graphql/handler.executor.DispatchOperation.func1.1(0xc0c740, 0xc0002c8f60, 0xc0002c8690)
/home/simon/go/pkg/mod/github.com/99designs/[email protected]/graphql/handler/executor.go:99 +0x130
github.com/99designs/gqlgen/graphql/handler/transport.POST.Do(0xc0ae40, 0xc0002922a0, 0xc00028e300, 0xc0b300, 0xc0000c0ff0)
/home/simon/go/pkg/mod/github.com/99designs/[email protected]/graphql/handler/transport/http_post.go:52 +0x353
github.com/99designs/gqlgen/graphql/handler.(Server).ServeHTTP(0xc0000d5e40, 0xc0ae40, 0xc0002922a0, 0xc00028e300)
/home/simon/go/pkg/mod/github.com/99designs/[email protected]/graphql/handler/server.go:140 +0x23c
net/http.(ServeMux).ServeHTTP(0x106d9c0, 0xc0ae40, 0xc0002922a0, 0xc00028e200)
/usr/local/go/src/net/http/server.go:2387 +0x1bd
net/http.serverHandler.ServeHTTP(0xc0002921c0, 0xc0ae40, 0xc0002922a0, 0xc00028e200)
/usr/local/go/src/net/http/server.go:2802 +0xa4
net/http.(conn).serve(0xc000270b40, 0xc0c680, 0xc000290b00)
/usr/local/go/src/net/http/server.go:1890 +0x875
created by net/http.(*Server).Serve
/usr/local/go/src/net/http/server.go:2928 +0x384

Gateway:

Encountered error when loading recommender-survey-archive at http://localhost:4004/query: 422: Unprocessable Entity

When the following graphql type is added everything works smoothly

type Workaround @key(fields: "id") {
  id: Int
}

Note: @key is required for this workaround

What did you expect?

I don't understand the details but I would expect gqlgen to add the following Query without the Workaround type, so that the service can be federated:

extend type Query {
   _entities(representations: [_Any!]!): [_Entity]!
   _service: _Service!
}

Minimal graphql.schema and models to reproduce

See above.

versions

• gqlgen version?

v0.11.1

• go version?

go version go1.13.6 linux/amd64

EDIT: Btw. I want to thank you for providing a go lib that allows to federate with apollo. You have created a really smooth technology that helps me a lot, great job and thank you!

[BitPhinix]

Same issue here.

That cost me nearly an hour to debug :sweat: always thought I fucked up somehow.

[yarinm]

I'm having the same issue,
gqlgen version is v0.11.2
@apollo/gateway: 0.13.2

@BitPhinix how did you solve it? Even the Todo example isn't working for me.

[BitPhinix]

@yarinm, I solved it by adding an dummy entity to the serivce (It isn't referenced by any query / mutation)

[krisanalfa]

Any update with this? I'm having the same problem.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[aaad]

I would suggest to keep this open.

[mtatarau90]

The same issue here. any news?

[jay-manday]

The workaround @aaad suggested works (ty, btw) but would be great if we could have a more permanent solution!