switch to type "module" for this project (ESM)

since it's still kind of small, it makes sense to switch to ESM, now.

.eslintrc

+{
+  "root": true,
+  "env": {
+    "node": true,
+    "es2021": true
+  },
+  "extends": [
+    "standard"
+  ]
+}

.eslintrc.js

-module.exports = {
-  root: true,
-  env: {
-    node: true,
-    es2021: true
-  },
-  extends: [
-    'standard'
-  ]
-}

jest.config.js

@@ -3,7 +3,7 @@
  * https://jestjs.io/docs/configuration
  */
 
-module.exports = {
+export default {
   // All imported modules in your tests should be mocked automatically
   // automock: false,
 

package.json

@@ -2,13 +2,14 @@
   "name": "manifest-service",
   "version": "1.0.0",
   "description": "Provides a combined manifest.json",
+  "type": "module",
   "main": "index.js",
   "scripts": {
     "lint": "eslint .",
     "start": "node index.js",
     "dev": "nodemon index.js | pino-pretty",
     "prepare": "husky install",
-    "test": "jest --no-cache"
+    "test": "NODE_OPTIONS=--experimental-vm-modules jest --no-cache"
   },
   "author": "Open-Xchange",
   "license": "CC-BY-NC-SA-2.5",
@@ -17,13 +18,13 @@
     "dotenv-defaults": "^2.0.1",
     "eslint-config-standard": "^16.0.2",
     "express": "^4.17.1",
+    "express-prom-bundle": "^6.4.1",
     "helmet": "^4.4.1",
     "js-yaml": "^4.0.0",
     "node-fetch": "^2.6.1",
     "pino": "^6.11.2",
     "pino-http": "^5.5.0",
     "prom-client": "^13.1.0",
-    "prometheus-api-metrics": "^3.2.0",
     "swagger-ui-express": "^4.1.6"
   },
   "devDependencies": {
@@ -34,7 +35,6 @@
     "eslint-plugin-jest": "^24.4.0",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-promise": "^5.1.0",
-    "fetch-mock-jest": "^1.5.1",
     "husky": ">=6",
     "jest": "^27.1.0",
     "jest-extended": "^0.11.5",

spec/.eslintrc

+{
+  "env": {
+    "jest/globals": true
+  },
+  "plugins": ["jest"]
+}

spec/.eslintrc.js

-module.exports = {
-  env: {
-    'jest/globals': true
-  },
-  plugins: ['jest']
-}

spec/server_test.js

-const { describe, it, expect, beforeAll, afterAll, beforeEach, afterEach } = require('@jest/globals')
-const mock = require('mock-fs')
-const fetchMock = require('node-fetch')
-const request = require('supertest')
-const createApp = require('../src/createApp')
-
-jest.mock('node-fetch', () => require('fetch-mock-jest').sandbox())
+import { describe, it, expect, beforeAll, afterAll, beforeEach, afterEach } from '@jest/globals'
+import mockfs from 'mock-fs'
+import request from 'supertest'
+import { createApp } from '../src/createApp'
+import { createMockServer, getRandomPort } from './util.js'
 
 describe('Manifest service', () => {
   let app
+  let mockserver
+  const port = getRandomPort()
 
   beforeAll(() => {
-    mock({
+    mockfs({
       './config/manifests': {
         'urls.yaml': `manifests:
-          - https://some-fake-url.k3s.de/api/manifest.json`
+          - http://localhost:${port}/api/manifest.json`
       }
     })
     app = createApp()
   })
 
   afterAll(() => {
-    mock.restore()
+    mockfs.restore()
   })
 
-  beforeEach(() => {
-    fetchMock.get('https://some-fake-url.k3s.de/api/manifest.json', JSON.parse('{"some":"thing"}'))
+  beforeEach(async () => {
+    mockserver = await createMockServer({ port })
+    mockserver.respondWith({
+      '/api/manifest.json': { some: 'thing' }
+    })
   })
 
   afterEach(() => {
-    fetchMock.restore()
+    mockserver.close()
     app.timeout = 30000
   })
 
   it('is healthy', async () => {
-    return await request(app)
-      .get('/healthy')
-      .then(response => {
-        expect(response.statusCode).toBe(200)
-      })
+    const response = await request(app).get('/healthy')
+    expect(response.statusCode).toBe(200)
   })
 
   it('fetches manifest data', async () => {
-    return await request(app)
-      .get('/api/manifest.json')
-      .then(response => {
-        expect(response.statusCode).toBe(200)
-        expect(response.body).toEqual([JSON.parse('{"some":"thing"}')])
-      })
+    const response = await request(app).get('/api/manifest.json')
+    expect(response.statusCode).toBe(200)
+    expect(response.body).toEqual([{ some: 'thing' }])
   })
 
   it('caches manifest data', async () => {
@@ -54,11 +51,12 @@ describe('Manifest service', () => {
       .get('/api/manifest.json')
       .then(response => {
         expect(response.statusCode).toBe(200)
-        expect(response.body).toEqual([JSON.parse('{"some":"thing"}')])
+        expect(response.body).toEqual([{ some: 'thing' }])
       })
 
-    fetchMock.restore()
-    fetchMock.get('https://some-fake-url.k3s.de/api/manifest.json', JSON.parse('{"some":"different"}'))
+    mockserver.close()
+    mockserver = await createMockServer({ port })
+    mockserver.respondWith({ '/api/manifest.json': { some: 'different' } })
 
     await new Promise((resolve, reject) => setTimeout(resolve, 150))
 
@@ -66,7 +64,7 @@ describe('Manifest service', () => {
       .get('/api/manifest.json')
       .then(response => {
         expect(response.statusCode).toBe(200)
-        expect(response.body).toEqual([JSON.parse('{"some":"thing"}')])
+        expect(response.body).toEqual([{ some: 'thing' }])
       })
   })
 
@@ -77,11 +75,12 @@ describe('Manifest service', () => {
       .get('/api/manifest.json')
       .then(response => {
         expect(response.statusCode).toBe(200)
-        expect(response.body).toEqual([JSON.parse('{"some":"thing"}')])
+        expect(response.body).toEqual([{ some: 'thing' }])
       })
 
-    fetchMock.restore()
-    fetchMock.get('https://some-fake-url.k3s.de/api/manifest.json', JSON.parse('{"some":"different"}'))
+    mockserver.close()
+    mockserver = await createMockServer({ port })
+    mockserver.respondWith({ '/api/manifest.json': { some: 'different' } })
 
     await new Promise((resolve, reject) => setTimeout(resolve, 150))
 
@@ -89,12 +88,12 @@ describe('Manifest service', () => {
       .get('/api/manifest.json')
       .then(response => {
         expect(response.statusCode).toBe(200)
-        expect(response.body).toEqual([JSON.parse('{"some":"different"}')])
+        expect(response.body).toEqual([{ some: 'different' }])
       })
   })
 
   it.skip('can load multiple configurations', async () => {
-    mock({
+    mockfs({
       './config/manifests': {
         'urls.yaml': `manifests:
           - https://some-fake-url.k3s.de/api/manifest.json
@@ -102,7 +101,9 @@ describe('Manifest service', () => {
       }
     })
 
-    fetchMock.get('https://some-other-fake-url.k3s.de/api/manifest.json', JSON.parse('{"some":"other"}'))
+    mockserver.close()
+    mockserver = await createMockServer({ port })
+    mockserver.respondWith({ '/api/manifest.json': { some: 'other' } })
 
     const app = createApp()
 
@@ -110,7 +111,7 @@ describe('Manifest service', () => {
       .get('/api/manifest.json')
       .then(response => {
         expect(response.statusCode).toBe(200)
-        expect(response.body).toEqual([JSON.parse('{"some":"thing"}'), JSON.parse('{"some":"other"}')])
+        expect(response.body).toEqual([{ some: 'thing"}' }, { some: 'other"}' }])
       })
   })
 })

spec/util.js

+import express from 'express'
+
+export function getRandomPort () {
+  return 1000 + (Math.random() * 39000) >> 0
+}
+
+export async function createMockServer ({ port }) {
+  const app = express()
+  const server = await new Promise(resolve => {
+    const server = app.listen(port, () => resolve(server))
+  })
+  server.respondWith = function (routes) {
+    for (const [route, data] of Object.entries(routes)) {
+      app.get(route, (req, res) => res.json(data))
+    }
+  }
+  return server
+}

src/createApp.js

 // Ignore paths for logging, metrics and docs
-const ignorePaths = ['/ready', '/healthy']
-
 // Fast, minimalist web framework for node.
-const express = require('express')
+import express from 'express'
 
 // Helmet helps you secure your Express app by setting various HTTP headers
-const helmet = require('helmet')
+import helmet from 'helmet'
 
 // Very low overhead Node.js logger. Logs in json use pino-pretty for dev.
-const logger = require('pino')()
+import Logger from 'pino'
 
 // Fastest HTTP logger for Node.js in town
-const httpLogger = require('pino-http')({ logger, autoLogging: { ignorePaths } })
-
+import pinoHttp from 'pino-http'
 // Readiness and liveness checks middleware
-const health = require('@cloudnative/health-connect')
+import health from '@cloudnative/health-connect'
 
 // Prometheus middleware for standard api metrics
-const apiMetrics = require('prometheus-api-metrics')
+import promBundle from 'express-prom-bundle'
 
 // Swagger UI for api-docs
-const swaggerUi = require('swagger-ui-express')
-const yaml = require('js-yaml')
-const fs = require('fs')
-const fetch = require('node-fetch')
-const swaggerDocument = yaml.load(fs.readFileSync('./swagger.yaml', 'utf8'))
+import swaggerUi from 'swagger-ui-express'
+import yaml from 'js-yaml'
+import fs from 'fs'
+import fetch from 'node-fetch'
+
+const ignorePaths = ['/ready', '/healthy']
+const logger = new Logger()
+const httpLogger = pinoHttp({ logger, autoLogging: { ignorePaths } })
+const swaggerDocument = yaml.load(fs.readFileSync('./src/swagger.yaml', 'utf8'))
+const bypass = (request) => ignorePaths.includes(request.path)
+const metricsMiddleware = promBundle({ bypass })
 
-module.exports = () => {
+export function createApp () {
   // The app returned by express() is in fact a JavaScript Function, designed to be passed to Node’s HTTP servers as a callback to handle requests.
 
   const app = express()
@@ -38,7 +41,7 @@ module.exports = () => {
   app.use(helmet())
   app.use('/healthy', health.LivenessEndpoint(healthCheck))
   app.use('/ready', health.ReadinessEndpoint(healthCheck))
-  app.use(apiMetrics({ excludeRoutes: ignorePaths }))
+  app.use(metricsMiddleware)
   app.use('/api-docs', swaggerUi.serve, swaggerUi.setup(swaggerDocument))
   app.use('/swagger.json', (req, res) => res.json(swaggerDocument))
 

index.js → src/index.js

 // Add env vars from files
 // Note: actual env vars supersede .env file and .env file supersedes .env.defaults file
-require('dotenv-defaults').config()
+import { config } from 'dotenv-defaults'
+import { logger } from 'pino'
+import { createApp } from './createApp'
 
-const logger = require('pino')()
-const createApp = require('./src/createApp')
+config()
 
 const app = createApp()