Issue with using keepAlive if set for 20 seconds or more

Question

Having a bit of trouble with keepAlive for Apollo subscriptions. When ever I set a time to seconds or more the listening subscriptions errors out.

{
  "error": "Could not connect to websocket endpoint ws://website.test:8000/graphql. Please check if the endpoint url is correct."
}

Here is ApolloServer setup

const apollo = new ApolloServer({
    introspection: true,
    playground: true,
    typeDefs: schema,
    subscriptions: {
      keepAlive: 40000,
    },
    resolvers,
    context: ........
}

In my local environment when I do not set keepAlive it will stay open indefinitely. If I set it at 10000 works great. With keep alive set at 40000 I get the error and connection closes

UPDATE One thing we just noticed is that this issue happens on the playground but not on our web app. Maybe just a playground thing?

I'm having a similar issue. I'm hoping there's a fix for this. — Alexis Tyler, Apr 27 '21 at 17:53
The error occurs immediately of after a certain period of inactivity (i.e. 30 sec) ? — Simon, Apr 29 '21 at 13:52
Does it work if you set keepAlive to 32767? That would point to something using a 16-bit signed integer. — Devon_C_Miller, May 04 '21 at 03:40
https://stackoverflow.com/users/98811/devon-c-miller Devon has a good argument. — Jin Thakur, May 04 '21 at 17:20

score 1 · Answer 1 · answered May 04 '21 at 16:42

If you check the documentation provided by Apollo GraphQL:

keepAlive - Number

The frequency with which the subscription endpoint should send keep-alive messages to open client connections, in milliseconds, if any.

If this value isn't provided, the subscription endpoint doesn't send keep-alive messages.

As per your provided configuration, with keep alive set at 40000, this is equivalent to 40 seconds. So the subscription endpoint is pinging keep-alive messages every 40 seconds. This probably is too long and the connections is already closed.

You should use a smaller value

The server is set to allow 60s and it still doesn't work with a lower value. — Alexis Tyler, May 04 '21 at 23:45

score 0 · Answer 2 · answered May 02 '21 at 14:57

0

If none if these help I suggest you open a issue on the Apollo repository:

I had the same issue just a few days ago. I resolved this by also adding the path option. Also declared the path inside of express middleware - https://www.reddit.com/r/graphql/comments/fpb3yt
WebSocket KeepAlive: WebSockets ping/pong, why not TCP keepalive?
How to handle WebSocket connection loss: Handling connection loss with websockets
Similar: Apollo Server - GraphQL's subscription websocket connection doesn't persist

answered May 02 '21 at 14:57

tscpp

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Changing the timeout to 10 seconds instead of 40 fixes the issue for me so I don't think it's anything todo with general web socket timeouts. It seems Apollo related. Apollo tends to point people back to stack overflow so opening an issue there likely isn't to help. Also none of these look like they're related to the issue. – Alexis Tyler May 03 '21 at 06:02

Issue with using keepAlive if set for 20 seconds or more

2 Answers2