1-error.txt

proxy_1            | 2017-05-26T11:24:27.715129487Z 172.20.0.1 - - [26/May/2017:11:24:27 +0000] "GET /_next/on-demand-entries-ping?page=/ HTTP/1.1" 200 27 "http://localhost:3000/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36"
app_1              | 2017-05-26T11:24:33.726024587Z   <-- GET /_next/on-demand-entries-ping?page=/
app_1              | 2017-05-26T11:24:33.727593387Z
app_1              | 2017-05-26T11:24:33.727633887Z   AssertionError: headers have already been sent
app_1              | 2017-05-26T11:24:33.727644987Z       at Object.set status [as status] (/service/node_modules/koa/lib/response.js:85:5)
app_1              | 2017-05-26T11:24:33.727675387Z       at Object.status (/service/node_modules/delegates/index.js:92:31)
app_1              | 2017-05-26T11:24:33.727689887Z       at Object.error (/service/node_modules/koa-errorhandler/index.js:76:21)
app_1              | 2017-05-26T11:24:33.727698187Z       at error.throw (<anonymous>)
app_1              | 2017-05-26T11:24:33.727705487Z       at onRejected (/service/node_modules/co/index.js:81:24)
app_1              | 2017-05-26T11:24:33.727712887Z
app_1              | 2017-05-26T11:24:33.727908987Z   xxx GET /_next/on-demand-entries-ping?page=/ 500 6ms -

2-server.js

const zlib = require('zlib')

const Koa = require('koa')
const Router = require('koa-router')
const koaBodyparser = require('koa-bodyparser')
const koaCompress = require('koa-compress')
const koaConvert = require('koa-convert')
const koaErrorHandler = require('koa-errorhandler')
const koaHelmet = require('koa-helmet')
const koaLogger = require('koa-logger')
const koaPassport = require('koa-passport')
const koaPing = require('koa-ping')
const koaRedis = require('koa-redis')
const koaResponseTime = require('koa-response-time')
const koaSession = require('koa-generic-session')
const koaStatic = require('koa-static')
const log = require('loglevel')
const next = require('next')

const {
  NODE_ENV,
  REDIS_HOST,
  REDIS_PORT,
  APP_HOST,
  APP_PORT,
  APP_KEYS,
} = process.env

if (NODE_ENV === 'develop') {
  log.setLevel('debug')
}

const nextApp = next({
  dev: process.env.NODE_ENV !== 'production',
})
const handleRequest = nextApp.getRequestHandler()

nextApp
  .prepare()
  .then(() => {
    const app = new Koa()
    app.keys = [APP_KEYS.split(',')]

    // Hook to convert old Koa.js middleware
    const oldUse = app.use
    app.use = x => oldUse.call(app, koaConvert(x))

    app
      .use(koaPing())
      .use(koaLogger())
      .use(koaErrorHandler())
      .use(koaBodyparser())
      .use(koaSession({
        rolling: true,

        store: koaRedis({
          host: REDIS_HOST,
          port: REDIS_PORT,
        }),
      }))
      .use(koaCompress({
        filter: contentType => /text/i.test(contentType),
        threshold: 2048,
        flush: zlib.Z_SYNC_FLUSH,
      }))
      .use(koaHelmet())
      .use(koaResponseTime())

    const router = new Router()

    router.get('*', (ctx) => {
      handleRequest(ctx.req, ctx.res)
      ctx.respond = false
    })

    app
      .use(async (ctx, next) => {
        ctx.res.statusCode = 200
        await next()
      })
      .use(router.routes())

    app.listen(APP_PORT, APP_HOST, (error) => {
      if (error) {
        throw error
      }

      log.info(`> Ready on http://${APP_HOST}:${APP_PORT}`)
    })
  })