Auto Reload of gateway for schema changes in federated service apollo GraphQL

Question

In Apollo Federation, I am facing this problem: The gateway needs to be restarted every time we make a change in the schema of any federated service in service list. I understand that every time a gateway starts and it collects all the schema and aggregates the data graph. But is there a way this can be handled automatically without restarting the Gateway as it will down all other unaffected GraphQL Federated services also

Apollo GraphQL , @apollo/gateway

Answer 1

There is an experimental poll interval you can use:

const gateway = new ApolloGateway({
  serviceList: [
    { name: "products", url: "http://localhost:4002" },
    { name: "inventory", url: "http://localhost:4001" },
    { name: "accounts", url: "http://localhost:4000" }
  ],
    debug: true,
    experimental_pollInterval:3000
})

the code above will pull every 3 seconds

Answer 2

I don't know other ways to automatically reload the gateway other than polling. I made a reusable docker image and i will keep updating it if new ways to reload the service emerge. For now you can use the POLL_INTERVAL env var to periodically check for changes. Here is an example using docker-compose:

version: '3'

services:
    a:
        build: ./a # one service implementing federation
    b:
        build: ./b
    gateway:
        image: xmorse/apollo-federation-gateway
        ports:
            - 8000:80
        environment: 
            CACHE_MAX_AGE: '5' # seconds
            POLL_INTERVAL: '30' # seconds
            URL_0: "http://a"
            URL_1: "http://b"