Log apollo-server GraphQL query and variables per request

Question

When using apollo-server 2.2.1 or later, how can one log, for each request, the query and the variables?

This seems like a simple requirement and common use case, but the documentation is very vague, and the query object passed to formatResponse no longer has the queryString and variables properties.

Answer 1

Amit's answer works (today), but IMHO it is a bit hacky and it may not work as expected in the future, or it may not work correctly in some scenarios.

For instance, the first thing that I thought when I saw it was: "that may not work if the query is invalid", it turns out that today it does work when the query is invalid. Because with the current implementation the context is evaluated before the the query is validated. However, that's an implementation detail that can change in the future. For instance, what if one day the apollo team decides that it would be a performance win to evaluate the context only after the query has been parsed and validated? That's actually what I was expecting :-)

What I'm trying to say is that if you just want to log something quick in order to debug something in your dev environment, then Amit's solution is definitely the way to go.

However, if what you want is to register logs for a production environment, then using the context function is probably not the best idea. In that case, I would install the graphql-extensions and I would use them for logging, something like:

const { print } = require('graphql');

class BasicLogging {
  requestDidStart({queryString, parsedQuery, variables}) {
    const query = queryString || print(parsedQuery);
    console.log(query);
    console.log(variables);
  }

  willSendResponse({graphqlResponse}) {
    console.log(JSON.stringify(graphqlResponse, null, 2));
  }
}

const server = new ApolloServer({
  typeDefs,
  resolvers,
  extensions: [() => new BasicLogging()]
});

Edit:

As Dan pointed out, there is no need to install the graphql-extensions package because it has been integrated inside the apollo-server-core package.

Answer 2

With the new plugins API, you can use a very similar approach to Josep's answer, except that you structure the code a bit differently.

const BASIC_LOGGING = {
    requestDidStart(requestContext) {
        console.log("request started");
        console.log(requestContext.request.query);
        console.log(requestContext.request.variables);
        return {
            didEncounterErrors(requestContext) {
                console.log("an error happened in response to query " + requestContext.request.query);
                console.log(requestContext.errors);
            }
        };
    },

    willSendResponse(requestContext) {
        console.log("response sent", requestContext.response);
    }
};


const server = new ApolloServer(
    {
        schema,
        plugins: [BASIC_LOGGING]
    }
)

server.listen(3003, '0.0.0.0').then(({ url }) => {
    console.log(`GraphQL API ready at ${url}`);
});