inventory.js

// Open Telemetry (optional)
const { ApolloOpenTelemetry } = require('supergraph-demo-opentelemetry');

if (process.env.APOLLO_OTEL_EXPORTER_TYPE) {
  new ApolloOpenTelemetry({
    type: 'subgraph',
    name: 'inventory',
    exporter: {
      type: process.env.APOLLO_OTEL_EXPORTER_TYPE, // console, zipkin, collector
      host: process.env.APOLLO_OTEL_EXPORTER_HOST,
      port: process.env.APOLLO_OTEL_EXPORTER_PORT,
    }
  }).setupInstrumentation();
}

const { ApolloServer, gql } = require('apollo-server');
const { buildSubgraphSchema } = require('@apollo/subgraph');
const { readFileSync } = require('fs');

const port = process.env.APOLLO_PORT || 4000;

const delivery = [
    { id: 'apollo-federation', estimatedDelivery: '6/25/2021', fastestDelivery: '6/24/2021' },
    { id: 'apollo-studio', estimatedDelivery: '6/25/2021', fastestDelivery: '6/24/2021' },
]

const typeDefs = gql(readFileSync('./inventory.graphql', { encoding: 'utf-8' }));
const resolvers = {
    Product: {
        delivery: (product, args, context) => {
            return delivery.find(p => p.id == product.id);
        }
    }
}
const server = new ApolloServer({ schema: buildSubgraphSchema({ typeDefs, resolvers }) });
server.listen( {port: port} ).then(({ url }) => {
  console.log(`🚀 Inventory subgraph ready at ${url}`);
}).catch(err => {console.error(err)});