feat(dataloader): create an example app that uses Apollo, koa, a data…

…loader, and Mongo or DynamoDB

Except for the dataloader, these are all things we instrument, so we
should be seeing spans for all of them once our instrumentation is
working.

And as far as I can tell... we do.

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