next.js/test/lib/next-modes/next-start.ts

import path from 'path'
import fs from 'fs-extra'
import { NextInstance } from './base'
import spawn from 'cross-spawn'
import { Span } from 'next/dist/trace'
import stripAnsi from 'strip-ansi'

export class NextStartInstance extends NextInstance {
  private _buildId: string
  private _cliOutput: string = ''
  private spawnOpts: import('child_process').SpawnOptions

  public get buildId() {
    return this._buildId
  }

  public get cliOutput() {
    return this._cliOutput
  }

  public async setup(parentSpan: Span) {
    super.setup(parentSpan)
    await super.createTestDir({ parentSpan })
  }

  private handleStdio = (childProcess) => {
    childProcess.stdout.on('data', (chunk) => {
      const msg = chunk.toString()
      process.stdout.write(chunk)
      this._cliOutput += msg
      this.emit('stdout', [msg])
    })
    childProcess.stderr.on('data', (chunk) => {
      const msg = chunk.toString()
      process.stderr.write(chunk)
      this._cliOutput += msg
      this.emit('stderr', [msg])
    })
  }

  public async start(options: { skipBuild?: boolean } = {}) {
    if (this.childProcess) {
      throw new Error('next already started')
    }

    this._cliOutput = ''
    this.spawnOpts = {
      cwd: this.testDir,
      stdio: ['ignore', 'pipe', 'pipe'],
      shell: false,
      env: {
        ...process.env,
        ...this.env,
        NODE_ENV: this.env.NODE_ENV || ('' as any),
        ...(this.forcedPort
          ? {
              PORT: this.forcedPort,
            }
          : {
              PORT: '0',
            }),
        __NEXT_TEST_MODE: 'e2e',
      },
    }

    let buildArgs = ['pnpm', 'next', 'build']
    let startArgs = ['pnpm', 'next', 'start']

    if (this.buildCommand) {
      buildArgs = this.buildCommand.split(' ')
    }

    if (this.buildArgs) {
      buildArgs.push(...this.buildArgs)
    }

    if (this.startCommand) {
      startArgs = this.startCommand.split(' ')
    }

    if (this.startArgs) {
      startArgs.push(...this.startArgs)
    }

    if (process.env.NEXT_SKIP_ISOLATE) {
      // without isolation yarn can't be used and pnpm must be used instead
      if (buildArgs[0] === 'yarn') {
        buildArgs[0] = 'pnpm'
      }
      if (startArgs[0] === 'yarn') {
        startArgs[0] = 'pnpm'
      }
    }

    if (!options.skipBuild) {
      console.log('running', buildArgs.join(' '))
      await new Promise<void>((resolve, reject) => {
        try {
          this.childProcess = spawn(
            buildArgs[0],
            buildArgs.slice(1),
            this.spawnOpts
          )
          this.handleStdio(this.childProcess)
          this.childProcess.on('exit', (code, signal) => {
            this.childProcess = undefined
            if (code || signal)
              reject(
                new Error(
                  `next build failed with code/signal ${code || signal}`
                )
              )
            else resolve()
          })
        } catch (err) {
          require('console').error(`Failed to run ${buildArgs.join(' ')}`, err)
          setTimeout(() => process.exit(1), 0)
        }
      })

      this._buildId = (
        await fs
          .readFile(
            path.join(
              this.testDir,
              this.nextConfig?.distDir || '.next',
              'BUILD_ID'
            ),
            'utf8'
          )
          .catch(() => '')
      ).trim()
    }

    console.log('running', startArgs.join(' '))
    await new Promise<void>((resolve, reject) => {
      try {
        this.childProcess = spawn(
          startArgs[0],
          startArgs.slice(1),
          this.spawnOpts
        )
        this.handleStdio(this.childProcess)

        this.childProcess.on('close', (code, signal) => {
          if (this.isStopping) return
          if (code || signal) {
            require('console').error(
              `next start exited unexpectedly with code/signal ${
                code || signal
              }`
            )
          }
        })

        const serverReadyTimeoutId = this.setServerReadyTimeout(
          reject,
          this.startServerTimeout
        )

        const readyCb = (msg) => {
          const colorStrippedMsg = stripAnsi(msg)
          if (colorStrippedMsg.includes('- Local:')) {
            this._url = msg
              .split('\n')
              .find((line) => line.includes('- Local:'))
              .split(/\s*- Local:/)
              .pop()
              .trim()
            this._parsedUrl = new URL(this._url)
          }

          if (this.serverReadyPattern!.test(colorStrippedMsg)) {
            clearTimeout(serverReadyTimeoutId)
            resolve()
            this.off('stdout', readyCb)
          }
        }
        this.on('stdout', readyCb)
      } catch (err) {
        require('console').error(`Failed to run ${startArgs.join(' ')}`, err)
        setTimeout(() => process.exit(1), 0)
      }
    })
  }

  public async build(
    options: { env?: Record<string, string>; args?: string[] } = {}
  ) {
    this.spawnOpts = {
      cwd: this.testDir,
      stdio: ['ignore', 'pipe', 'pipe'],
      shell: false,
      env: {
        ...process.env,
        ...this.env,
        ...options.env,
        NODE_ENV: '' as any,
        PORT: this.forcedPort || '0',
        __NEXT_TEST_MODE: 'e2e',
      },
    }
    return new Promise<{
      exitCode: NodeJS.Signals | number | null
      cliOutput: string
    }>((resolve) => {
      const curOutput = this._cliOutput.length
      const buildArgs = ['pnpm', 'next', 'build']

      if (this.buildArgs) {
        buildArgs.push(...this.buildArgs)
      }

      if (options.args) {
        buildArgs.push(...options.args)
      }

      if (this.childProcess) {
        throw new Error(
          `can not run export while server is running, use next.stop() first`
        )
      }

      console.log('running', buildArgs.join(' '))

      this.childProcess = spawn(
        buildArgs[0],
        buildArgs.slice(1),
        this.spawnOpts
      )
      this.handleStdio(this.childProcess)

      this.childProcess.on('exit', (code, signal) => {
        this.childProcess = undefined
        resolve({
          exitCode: signal || code,
          cliOutput: this.cliOutput.slice(curOutput),
        })
      })
    })
  }
}