feat(dataloader): create an example app that uses Apollo, koa, a dataloader and Mongo

graphql-koa-dataloader/Dockerfile

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+FROM node:lts-slim
+EXPOSE 4000
+
+RUN apt-get update && apt-get install httpie jq -y
+
+WORKDIR /app
+COPY app .
+COPY entrypoint.sh /entrypoint.sh
+RUN npm ci
+
+ENTRYPOINT ["/entrypoint.sh"]

graphql-koa-dataloader/README.md

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+This is an example of an Apollo server using the Koa middleware and dataloader
+
+Get it running:
+
+1. Copy sample.env to .env
+2. Edit .env to add your New Relic ingest key, and any other desired changes.
+3. Start with `docker-compose up --build`.

graphql-koa-dataloader/app/.eslintrc.cjs

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+/*
+ * Copyright 2022 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+'use strict'
+
+module.exports = {
+  extends: '@newrelic',
+  parserOptions: {
+    ecmaVersion: 'latest'
+  },
+  rules: {
+    'no-console': 'off',
+    'func-names': 'off'
+  }
+}

graphql-koa-dataloader/app/context.js

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+/*
+ * Copyright 2023 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import DataLoader from 'dataloader'
+import { getUserById } from './datastore.js'
+
+const loaders = () => ({
+  getUserById: new DataLoader(
+    (ids) => {
+      return Promise.all(ids.map((id) => getUserById(Number(id))))
+    },
+    {
+      batchScheduleFn: (callback) => setTimeout(callback, 100)
+    }
+  )
+})
+
+const getContext = () => {
+  return {
+    loaders: loaders()
+  }
+}
+
+export default getContext

graphql-koa-dataloader/app/datastore-dynamodb.js

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+/*
+ * Copyright 2023 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  DynamoDBClient as Client,
+  CreateTableCommand,
+  DeleteTableCommand,
+  waitUntilTableExists,
+  waitUntilTableNotExists
+} from '@aws-sdk/client-dynamodb'
+import { DynamoDBDocumentClient, GetCommand, PutCommand } from '@aws-sdk/lib-dynamodb'
+import { generateUsers } from './utils.js'
+
+const tableParams = {
+  AttributeDefinitions: [
+    {
+      AttributeName: 'id',
+      AttributeType: 'N'
+    }
+  ],
+  KeySchema: [
+    {
+      AttributeName: 'id',
+      KeyType: 'HASH'
+    }
+  ],
+  ProvisionedThroughput: {
+    ReadCapacityUnits: 1,
+    WriteCapacityUnits: 1
+  },
+  TableName: 'Users',
+  StreamSpecification: {
+    StreamEnabled: false
+  }
+}
+
+async function initData() {
+  const client = new Client({})
+  try {
+    console.log('Deleting table...')
+    await client.send(new DeleteTableCommand({ TableName: 'Users' }))
+    await waitUntilTableNotExists({ client }, { TableName: 'Users' })
+  } catch (err) {
+    console.log(err.message)
+  }
+  console.log('Creating table...')
+  await client.send(new CreateTableCommand(tableParams))
+  await waitUntilTableExists({ client }, { TableName: 'Users' })
+
+  console.log('Adding users...')
+  const docClient = DynamoDBDocumentClient.from(client)
+  const users = generateUsers(10)
+  for (const user of users) {
+    user.id = user._id
+    await docClient.send(
+      new PutCommand({
+        TableName: 'Users',
+        Item: user
+      })
+    )
+  }
+  console.log('added 10 users')
+}
+
+async function getUserById(id) {
+  const client = DynamoDBDocumentClient.from(new Client({}))
+  const { Item: item } = await client.send(
+    new GetCommand({
+      TableName: 'Users',
+      Key: { id }
+    })
+  )
+  return item
+}
+
+export { getUserById, initData }

graphql-koa-dataloader/app/datastore-mongo.js

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+/*
+ * Copyright 2023 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { MongoClient } from 'mongodb'
+import { generateUsers } from './utils.js'
+
+async function initData() {
+  const client = new MongoClient(process.env.MONGO_URL)
+  try {
+    await client.connect()
+    const allUsers = generateUsers(10)
+    const db = client.db('users')
+    const friends = db.collection('friends')
+    await friends.deleteMany()
+
+    const result = await friends.insertMany(allUsers, { ordered: true })
+    console.log(`${result.insertedCount} users were created`)
+  } finally {
+    client.close()
+  }
+}
+
+async function getUserById(id) {
+  console.log(`Fetch user #${id}`)
+  const client = new MongoClient(process.env.MONGO_URL)
+  try {
+    await client.connect()
+    const db = client.db('users')
+    const friends = db.collection('friends')
+    const result = await friends.findOne({ _id: id })
+    console.log(result)
+    return result
+  } finally {
+    client.close()
+  }
+}
+
+export { getUserById, initData }

graphql-koa-dataloader/app/datastore.js

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+/*
+ * Copyright 2023 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import * as dynamodb from './datastore-dynamodb.js'
+import * as mongo from './datastore-mongo.js'
+
+async function initData() {
+  if (process.env.NEW_RELIC_DATASTORE?.toLowerCase() === 'dynamodb') {
+    return await dynamodb.initData()
+  }
+  if (process.env.NEW_RELIC_DATASTORE?.toLowerCase() === 'mongo') {
+    return await mongo.initData()
+  }
+  throw new Error(
+    'Unknown datastore. Set the "NEW_RELIC_DATASTORE" environment variable to either "DynamoDB" or "Mongo"'
+  )
+}
+
+async function getUserById(id) {
+  if (process.env.NEW_RELIC_DATASTORE?.toLowerCase() === 'dynamodb') {
+    return await dynamodb.getUserById(id)
+  }
+  if (process.env.NEW_RELIC_DATASTORE?.toLowerCase() === 'mongo') {
+    return await mongo.getUserById(id)
+  }
+  throw new Error(
+    'Unknown datastore. Set the "NEW_RELIC_DATASTORE" environment variable to either "DynamoDB" or "Mongo"'
+  )
+}
+
+export { getUserById, initData }

graphql-koa-dataloader/app/make-requests.sh

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+#!/bin/bash
+shopt -s expand_aliases
+
+alias http='http --print b --ignore-stdin'
+
+echo "Starting request loop"
+while true; do
+
+  # Get all users
+  echo "Fetching all users"
+  http localhost:4000 query='{allUsers{age, email, hobbies, id, name, friends}}' | jq -C
+
+  for id in {1..10}; do
+    echo "Fetching user #${id}"
+    http localhost:4000 query="{user(id:${id}){age, email, hobbies, id, name, friends}}" | jq -C
+  done
+  sleep 5
+done