Polyglot Microservices: Federated Subscriptions in Golang, Rust, and Node.js, Final

Series Navigation

1. Golang Microservices (spells)
2. Rust Microservice (messages)
3. Node.js Microservice (players)
4. Gateway

Hive Gateway (Node.js)

Now, let's tie it all together with the Hive Gateway, made by the awesome team, "TheGuild" over on GitHub.

First, let's create the node project with Nx:

nx g @nx/node:application

Install a few dependencies:

pnpm i @graphql-hive/gateway graphql-ws ws

Add a config in src/gateway.config.ts:

import { defineConfig, LogLevel } from '@graphql-hive/gateway';

export const gatewayConfig = defineConfig({
  port: 8000,
  supergraph: 'apps/gateway/supergraph.graphql',
  logging: LogLevel.debug,
  transportEntries: {
    '*.http': {
      options: {
        subscriptions: {
          kind: 'ws',
        },
      },
    },
  },
});

Let's add a few commands to this project, too:

...
    "hive-gateway": {
      "dependsOn": ["supergraph-compose"],
      "executor": "nx:run-commands",
      "options": {
        "command": "node_modules/.bin/hive-gateway supergraph -c apps/gateway/src/gateway.config.ts"
      }
    },
    "supergraph-compose": {
      "executor": "nx:run-commands",
      "options": {
        "command": "rover supergraph compose --elv2-license=accept --config apps/gateway/supergraph.json --output apps/gateway/supergraph.graphql"
      }
    },
...

Add a supergraph config for supergraph.json:

{
  "federation_version": "=2.9.0",
  "subgraphs": {
    "spells": {
      "schema": {
        "subgraph_url": "http://localhost:8080/query"
      }
    },
    "messages": {
      "schema": {
        "subgraph_url": "http://localhost:8081"
      }
    },
    "players": {
      "schema": {
        "subgraph_url": "http://localhost:8082/graphql"
      }
    }
  }
}

Okay, let's test this out and run the subgraphs first:

nx run-many -t=serve -p player-service message-service spell-service

Now, let's run the gateway:

NOTE: rover CLI is required for this step.

nx run gateway:hive-gateway

You should be able to run and execute Subscriptions through the gateway! Nice! You've now got a polyglot federated supergraph with subscriptions!

If you'd like to see the code, check it out here: https://github.com/sutt0n/polyglot-fed-gql