Apollo server 4 and subgraphs

[praneetheus]

My project is using Apollo server 4 and graphql-modules 2.4.0. I am using the workaround described here #2270 to get the graphql-modules working.

const server = new ApolloServer({
    // schema: application.createSchemaForApollo() // graphql-modules has marked this deprecated, but works with Apollo Server 4.
    // Recommended approach is to use gateway:
    gateway: {
        async load() {
            return { executor: application.createApolloExecutor() };
        },
        onSchemaLoadOrUpdate(callback) {
            callback({ apiSchema: application.schema } as any);
            return () => {};
        },
        async stop() {},
    },
});

I want to implement a subgraph and I am following the documentation here, https://www.apollographql.com/docs/apollo-server/using-federation/apollo-subgraph-setup, but I can't pass both schema and gateway to the ApolloServer constructor.

The only workaround I found is to use the deprecated createSchemaForApollo , with this, modules work with subgraph, but I rather not rely on deprecated functions if possible.

Has anyone encountered this issue? Any potential solutions for this?

[kooroshkz]

Hey

You're right — ApolloServer doesn't allow using both gateway and schema together. If you're building a subgraph (not a gateway), then gateway shouldn't be used at all.

For graphql-modules + Apollo Server 4 as a subgraph, the better approach is:

import { buildSubgraphSchema } from '@apollo/subgraph';
import { ApolloServer } from '@apollo/server';

const schema = buildSubgraphSchema({
  typeDefs: application.typeDefs,
  resolvers: application.resolvers,
});

const server = new ApolloServer({ schema });

createSchemaForApollo() works but is deprecated, and using buildSubgraphSchema directly gives you more control and is future-proof.

Hope this helps!
If it does, feel free to mark it as the answer so it can help others too.

[praneetheus]

Hi, I did try that but I get context.egetModuleContext is not a function error