Built-in server support for subscriptions

[jasonkuhrt]

Perceived Problem

• GraphQL subscriptions are cool
• Once we support them subscriptionType is not supported yet #447 we'll still have another issue...
• Server support for them is required
• Tools like AppSync have set the bar high on what users expect

Ideas / Proposed Solution(s)

• Nexus can help
• Nexus serverful should have websockets out of the box
  • A classic is https://socket.io/
  • via @timsuchanek https://github.com/uNetworking/uWebSockets.js
  • via @danielmahon https://github.com/apollographql/subscriptions-transport-ws
• Nexus serverless should integrate with websocket-like solutions of platforms. (example: WebSocket APIs in API Gateway)

[danielmahon]

Just throwing another option out there for reference, though I'm sure you'd rather build it directly into the framework: https://github.com/apollographql/subscriptions-transport-ws works well and works "now" with the current nexus if you pass it the HTTP server and schema. Uses https://www.npmjs.com/package/ws under the hood. See my comment in #447 for how I'm using it to support subscriptions in the current nexus build. (the plugin nexus-plugin-subscriptions just wraps subscriptions-transport-ws)

[jasonkuhrt]

Thanks @danielmahon adding that possibility into the OP 👍

[jasonkuhrt]

Saw this via colleague should be something that is easy to build with Nexus down the line https://databaselog.com/ (in part if/when Prisma has real-time support too)

[jasonkuhrt]

Maybe relevant library for us https://github.com/apollographql/graphql-subscriptions. But looks inactive.

[danielmahon]

@jasonkuhrt It's been working in my setup with nexus/prisma so far, but yeah I'm unsure of its future. Although the latest stable Apollo server is still using it... 🤔 , and I don't see them dropping subscription support anytime soon. I haven't dug very far into its code yet but the main issue with its current state seems to be a memory leak with the withFilter function (apollographql/graphql-subscriptions#209). I've tested the fork too and had no issues using it combined with Google's PubSub and over 100k+ updates/day.

[leungandrew]

@danielmahon with #1050 you don't need your fork of Nexus anymore and can go back to using the latest. I was able to get subscriptions working with your plugin by doing the following:

use(
  subscriptions({
    ws: { server: server.raw.http, path: '/graphql' }, // use server.raw.http here
    keepAlive: 10 * 1000,
    onConnect: (payload: Record<string, any>) => {
      log.info('client connected')
      // return ctx
      return { pubsub, db, log }
    },
    onDisconnect: () => {
      log.info('client disconnected')
    },
  }),
)

Cheers and thanks for the plugin!

[Sytten]

The subscriptions-transport-ws package has effectively not been updated for two years and has a lot of bugs in it (still marked work in progress even though everybody uses it in prod). One thing that is very annoying is it generally not well integrated in the apollo server for the lifecycle of a request, error management, context creation, etc. It feels like subscriptions are second-class citizens instead of being as nice to use as queries and mutations. I would really like to see a new implementation of the transport layer. As for the graphql-subscriptions package, it is worth keeping to access all the plugins the community created.

[jasonkuhrt]

Thanks for the input @Sytten. Indeed everything you're saying lines up with how I suspected things were. There's also issues with context management deeper down the lib stack graphql/graphql-js#894.

Do you have any lib suggestions we could add to our list of possible tools to use above?

[Sytten]

Interesting, I don't think the apollo implementation suffers from the issue mentioned in GraphQLjs. They do create a new context on each message as far as i can tell.

I think it would be nice to have a generic transport interface that could be changed by the user. Websocket is ok for most cases, but one might want to use Pusher in a serverless case or another third party.

[paniavula]

First class support for subscription transport interface would be really helpful

[jasonkuhrt]

This will be closed soon as we're building on top of Apollo Server now which provides subscriptions support.

[Sytten]

Seems fair, but please keep an eye on their implementation since it is pretty bad currently.

[jasonkuhrt]

@Sytten we're open to something better in the future and in serverless will need a whole other technical solution too (e.g. seamless AWS API Gateway Websockets, Pusher, etc. integration).

[brielov]

I see you've added subscriptionType on 0.26 and you're already using apollo-server-express so I went ahead and tried it and graphql playground throws:

Could not connect to websocket endpoint ws://localhost:4000/graphql. Please check if the endpoint url is correct.

Am I missing some configuration or it isn't ready for testing yet?

[jasonkuhrt]

@brielov isn't ready yet. When this issue is closed, it will be though.

[brielov]

@jasonkuhrt Sorry, my bad. Thank you!

[brielov]

Any news on this?

[Albert-Gao]

Could there be two modes for the subscription?

1. Serverful mode
2. AWS Serverless mode integrates with WebSocket from API Gateway

[jasonkuhrt]

@Albert-Gao yes that's my vision. Add in others too, like pusher. Be pluggable etc.

I will try to push something in the near future that puts the Apollo Server subscriptions server to use. PRs welcome. My plan is that if you use Subscription type in your schema it will be automatically enabled, otherwise automatically disabled, and then manual overrides will be possible too.

[Albert-Gao]

Looks great, seems the code is already merged!

Just got a great idea, we can use the local apollo for testing subscription, and using AWS API gateway(or other services) for actual deployment... Not a 1-to-1 matching env for sure, but solves the painpoint of serverless dev in an elegant way, since if the abstraction from nexus is stable, that is the part we should not worry about.

What a beautiful future.