aaronpowell
CosmosDB GraphQL Subscriptions 
This package contains support for Apollo GraphQL Subscriptions, using the Azure CosmosDB Change Feed.
Installation
Install via npm or GitHub Packages:
$> npm install --save @aaronpowell/graphql-cosmosdb-subscriptionsUsage
You'll need a SignalR Service account (if you don't have an Azure account sign up for free). Copy the connection string and provide it when you create an instance of SignalRPubSub:
import { CosmosDBPubSub } from "@aaronpowell/graphql-cosmosdb-subscriptions";
const cosmosPubSub = new CosmosDBPubSub(
new CosmosClient(process.env.COSMOS_CONNECTION_STRING || "")
.database(process.env.COSMOS_DB || "")
.container(process.env.COSMOS_CONTAINER || "")
);Unlike most pubsub libraries, you don't need to publish directly, messages are received when the Change Feed receives messages. When creating the subscription, you subscribe to a CosmosDB partition key value (in the below example type is the partition key and we're subscription when type = 'message').
export const resolvers = {
Query: {
async hello(parent, args, { dataSources }) {
const text = `Message! ${Date.now()}`;
await dataSources.messages.createOne({
id: Date.now() + "",
text,
type: "message",
});
return text;
},
},
Subscription: {
getMessage: {
subscribe: () => cosmosPubSub.asyncIterator(["message"]),
},
},
};