blobpack/lib/install.js

Packaging Benthos configs for AWS Lambda was too exciting, now it's acceptably boring.

import crypto from 'crypto'
import fs from 'fs'
import path from 'path'

import download from 'download'
import mkdirp from 'mkdirp'

import { zipName } from './zip-name.js'
import { loadConfig } from './config.js'

export const install = async ({
  configPath = 'package.json',
  tmpRoot = 'tmp',
  logger = console
} = {}) => {
  try {
    const config = await loadConfig(configPath)
    const { data, name } = await pull(config)
    await write(tmpRoot, name, data)
    const outputPath = path.resolve(tmpRoot, name)
    logger.log(`Verified ${outputPath}`)
    return outputPath
  } catch (err) {
    logger.error(err)
    throw err
  }
}

const pull = async (benthos) => {
  const { name, data, checksums } = await get(benthos)
  verify(name, checksums, data)
  return { data, name }
}

const get = async (benthos) => {
  const root = `${benthos.src}/v${benthos.version}`
  const name = zipName(benthos)

  const [data, checksums] = await Promise.all([
    download(`${root}/${name}`),
    download(
      `${root}/${benthos.checksumPrefix}_${benthos.version}_checksums.txt`
    )
  ])

  return { name, data, checksums }
}

const verify = (name, checksums, data) => {
  const checksum = checksums
    .toString()
    .split('\n')
    .find((s) => s.endsWith(name))
    .split('  ')[0]

  const sha = crypto.createHash('sha256').update(data).digest('hex')
  if (checksum !== sha) {
    throw new Error(
      `Failed to verify sha256 for ${name}. Expected ${checksum}, got ${sha}`
    )
  }
}

const write = async (tmpRoot, name, data) => {
  const root = path.resolve(tmpRoot)
  const dst = path.resolve(root, name)
  await mkdirp(root)
  await fs.promises.writeFile(dst, data)
}