deploy

#!/usr/bin/env node

// [start-readme]
//
// This script is run by a GitHub Actions workflow to trigger deployments
// to Heroku for both staging and production apps.
//
// You can also run it locally if you:
//  - Supply a GitHub PAT as the GITHUB_TOKEN environment variable
//  - Supply a Heroku API token as the HEROKU_API_TOKEN environment variable
//  - Optionally, supply a GitHub PAT as the DOCUBOT_REPO_PAT environment
//    variable if you want to support content from the `docs-early-access` repo
//
// Examples:
//  - Deploy a PR to Staging:
//      script/deploy --staging https://github.com/github/docs-internal/pull/12345
//
//  - Deploy a PR to Staging and force the Heroku App to be rebuilt from scratch:
//      script/deploy --staging https://github.com/github/docs/pull/9876 --rebuild
//
//  - Undeploy a PR from Staging by deleting the Heroku App:
//      script/deploy --staging https://github.com/github/docs/pull/9876 --destroy
//
//  - Deploy the latest from docs-internal `main` to production:
//      script/deploy --production
//
// [end-readme]

require('dotenv').config()
const { GITHUB_TOKEN, HEROKU_API_TOKEN } = process.env

// Exit if GitHub Actions PAT is not found
if (!GITHUB_TOKEN) {
  throw new Error('You must supply a GITHUB_TOKEN environment variable!')
}

// Exit if Heroku API token is not found
if (!HEROKU_API_TOKEN) {
  throw new Error('You must supply a HEROKU_API_TOKEN environment variable!')
}

const program = require('commander')
const { has } = require('lodash')
const getOctokit = require('./helpers/github')
const parsePrUrl = require('./deployment/parse-pr-url')
const deployToStaging = require('./deployment/deploy-to-staging')
const undeployFromStaging = require('./deployment/undeploy-from-staging')

const STAGING_FLAG = '--staging'
const PRODUCTION_FLAG = '--production'
const ALLOWED_OWNER = 'github'
const ALLOWED_SOURCE_REPOS = ['docs', 'docs-internal']
const EXPECTED_PR_URL_FORMAT = `https://github.com/${ALLOWED_OWNER}/(${ALLOWED_SOURCE_REPOS.join('|')})/pull/123`

program
  .description('Trigger a deployment to Heroku for either staging or production apps')
  .option(PRODUCTION_FLAG, 'Deploy the latest internal main branch to Production')
  .option(`${STAGING_FLAG} <PR_URL>`, 'Deploy a pull request to Staging')
  .option('--rebuild', 'Force a Staging deployment to rebuild the Heroku App from scratch')
  .option('--destroy', 'Undeploy a Staging deployment by deleting the Heroku App')
  .parse(process.argv)

const opts = program.opts()
const isProduction = opts.production === true
const isStaging = has(opts, 'staging')
const prUrl = opts.staging
const forceRebuild = opts.rebuild === true
const destroy = opts.destroy === true

//
// Verify CLI options
//
if (!isProduction && !isStaging) {
  return invalidateAndExit(
    'commander.missingArgument',
    `error: must specify option '${STAGING_FLAG} <PR_URL>' or '${PRODUCTION_FLAG}'`
  )
}

if (isProduction && isStaging) {
  return invalidateAndExit(
    'commander.conflictingArgument',
    `error: must specify option '${STAGING_FLAG} <PR_URL>' or '${PRODUCTION_FLAG}' but not both`
  )
}

if (isProduction && forceRebuild) {
  return invalidateAndExit(
    'commander.conflictingArgument',
    `error: cannot specify option '--rebuild' combined with option '${PRODUCTION_FLAG}'`
  )
}

if (isProduction && destroy) {
  return invalidateAndExit(
    'commander.conflictingArgument',
    `error: cannot specify option '--destroy' combined with option '${PRODUCTION_FLAG}'`
  )
}

// Extract the repository name and pull request number from the URL (if any)
const { owner, repo, pullNumber } = parsePrUrl(prUrl)

if (isStaging) {
  if (owner !== ALLOWED_OWNER || !ALLOWED_SOURCE_REPOS.includes(repo) || !pullNumber) {
    return invalidateAndExit(
      'commander.invalidOptionArgument',
      `error: option '${STAGING_FLAG}' argument '${prUrl}' is invalid.
Must match URL format '${EXPECTED_PR_URL_FORMAT}'`
    )
  }
}

deploy()

//
// Function definitions
//

function invalidateAndExit (errorType, message) {
  program._displayError(1, errorType, message)
  process.exit(1)
}

async function deploy () {
  if (isProduction) {
    await deployProduction()
  } else if (isStaging) {
    await deployStaging({ owner, repo, pullNumber, forceRebuild, destroy })
  }
}

async function deployProduction () {
  // TODO: Request confirmation before deploying to production

  return invalidateAndExit(
    'commander.invalidOptionArgument',
    `error: option '${PRODUCTION_FLAG}' is not yet implemented. SOON!`
  )
}

async function deployStaging ({ owner, repo, pullNumber, forceRebuild = false, destroy = false }) {
  // This helper uses the `GITHUB_TOKEN` implicitly
  const octokit = getOctokit()

  const { data: pullRequest } = await octokit.pulls.get({
    owner,
    repo,
    pull_number: pullNumber
  })

  try {
    if (destroy) {
      await undeployFromStaging({
        herokuToken: HEROKU_API_TOKEN,
        octokit,
        pullRequest
      })
    } else {
      await deployToStaging({
        herokuToken: HEROKU_API_TOKEN,
        octokit,
        pullRequest,
        forceRebuild
      })
    }
  } catch (error) {
    const action = destroy ? 'undeploy from' : 'deploy to'
    console.error(`Failed to ${action} staging: ${error.message}`)
    console.error(error)
    process.exit(1)
  }
}