问题描述
我们使用 GraphQL 订阅和发布订阅来订阅帖子.
We are using GraphQL Subscriptions and pubsub to subscribe to posts.
当订阅超过 10 个时,我们会收到节点警告MaxListenersExceededWarning:检测到可能的 EventEmitter 内存泄漏."
When more than 10 subscriptions occur we get the the node warning "MaxListenersExceededWarning: Possible EventEmitter memory leak detected."
是否可以在 pubsub 类中提高最大听众数?
Is it possible to raise the max listeners in the pubsub class?
pubsub 类位于一个单独的模块中,如下所示:
The pubsub class is inside a separate module and looks like this:
import { PubSub } from 'graphql-subscriptions';
const pubsub = new PubSub();
export { pubsub };
订阅服务器如下所示:
import { SubscriptionManager } from 'graphql-subscriptions';
import { createServer } from 'http';
import { SubscriptionServer } from 'subscriptions-transport-ws';
import { pubsub } from './subscriptions';
import executableSchema from './executableSchema';
const WS_PORT = 8080;
const websocketServer = createServer((request, response) => {
response.writeHead(404);
response.end();
});
websocketServer.listen(WS_PORT, () => console.log(
`Websocket Server is now running on http://localhost:${WS_PORT}`
));
const subscriptionManager = new SubscriptionManager({
schema: executableSchema,
pubsub: pubsub,
setupFunctions: {
newPost: (options, args) => {
return {
newPostChannel: {
filter: (post) => {
return args.publicationId === post.relatedPublication.id;
}
},
};
},
},
});
const subscriptionServer = new SubscriptionServer({
subscriptionManager: subscriptionManager
}, {
server: websocketServer,
path: '/',
});
export {
subscriptionServer,
};
推荐答案
我编写了您正在使用的 graphql-subscriptions 包的原始实现,因此我可以在此处提供一些上下文.
I wrote the original implementation of the graphql-subscriptions package you're using, so I can provide some context here.
graphql-subscriptions 中包含的简单 EventEmitter pubsub 库仅用于演示目的.EventEmitter 并不能真正扩展到大量数据,它们在内存中,并且只有在您只有一台服务器时才能工作.
The simple EventEmitter pubsub library included in graphql-subscriptions is only intended for demo purposes. EventEmitters don't really scale to large numbers, they're in-memory, and they'll only work as long as you have no more than a single server.
对于尝试在生产中运行 GraphQL 订阅的任何人,我强烈建议使用不同的系统,例如 Redis 或 MQTT 通过 graphql-redis-subscriptions 或 graphql-mqtt-subscriptions.这将具有保持 GraphQL 服务器无状态(除了 websockets)的优势,因此易于水平扩展.
For anyone trying to run GraphQL subscriptions in production, I strongly recommend using a different system, for example Redis or MQTT through graphql-redis-subscriptions or graphql-mqtt-subscriptions. This will have the advantage of keeping the GraphQL server stateless (apart from the websockets) and thus easy to scale horizontally.
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