ApolloServer.logger should probably be public readonly in AS4

[codedawi]

Proposal

We would like to propose exposing the logger property of ApolloServerBase class that is currently private to any class that extends it by updating it to a protected property.

apollo-server/packages/apollo-server-core/src/ApolloServer.ts

Lines 127 to 131 in fca56e7

	export class ApolloServerBase<
	// The type of the argument to the `context` function for this integration.
	ContextFunctionParams = any,
	> {
	private logger: Logger;

Use case

We have extend the ApolloServerBase class using the serverless approach by implementing a custom handler. We would like to add logging in our handler method but do not want to use console or some global logger. We would like to access the this.logger property configured on initialization of the base class. We do not override constructor function and would prefer not for this a hack around the logger initialization.

export class CustomApolloServerless extends ApolloServerBase {
    protected override serverlessFramework(): boolean {
        return true;
    }
    public createHandler() {
        this.logger.info("Initializing serverless handler...");
        
        return async (request: GraphQLRequest, context: any): Promise<GraphQLResponse> => {
            this.logger.debug(`Handling request ${context.requestId}...`);
        }
    }
}

[glasser]

Our plan for Apollo Server 4 (see https://github.com/apollographql/apollo-server/blob/main/ROADMAP.md and https://github.com/apollographql/apollo-server/milestone/60) is to change ApolloServer from having a subclass-based API to having a more well-defined public API that you extend by writing separate "createHandler" functions that take the single ApolloServer as an argument. So changing logger to protected definitely won't make sense there. But it might make sense to expose logger as part of ApolloServer's public API, for this exact use case. Right now we're pretty focused on getting AS4 from "started" to "finished" as fast as possible so I'm not sure it makes sense to prioritize fixing this in AS3. I'm going to change this to an issue on the AS4 milestone to consider making logger public.

In the meantime, I don't see any reason we would get rid of ApolloServerBase.logger in AS3, so as a workaround you can write this['logger'], which is a legitimate and type-safe way in TypeScript to access private properties. ie, feel free to consider this as a stable part of the AS3 API even though it is private.

[glasser]

Probably cache too.

[glasser]

Fixed in version-4 in #6668