server.js

#!/usr/bin/env node

/*
  S3Proxy Hono Server

  Docker runtime for s3proxy (https://github.com/gmoon/s3proxy) v4.
  Streams objects from an S3 bucket over HTTP using the v4 `proxy.fetch()`
  API and Hono on top of @hono/node-server.

  Start: PORT=8080 BUCKET=my-bucket node server.js

  Author: George Moon <george.moon@gmail.com>
*/

import fs from 'node:fs'
import process from 'node:process'
import { serve } from '@hono/node-server'
import { Hono } from 'hono'
import { S3Proxy } from 's3proxy'

const PORT = Number(process.env.PORT) || 8080
const BUCKET = process.env.BUCKET
const NODE_ENV = process.env.NODE_ENV || 'production'
const S3PROXY_VERSION = S3Proxy.version()

if (!BUCKET) {
  console.error('❌ Missing required environment variable: BUCKET')
  process.exit(1)
}

// Development credential handling. In production the AWS SDK credential chain is
// used (instance role, env vars, etc.). In development a temporary credentials
// file can be mounted at the working directory (see `npm run credentials`).
function getCredentials() {
  if (/^prod/i.test(NODE_ENV)) {
    return undefined
  }
  const file = './credentials.json'
  try {
    const { Credentials } = JSON.parse(fs.readFileSync(file, 'utf8'))
    console.log(`using credentials from ${file}`)
    return {
      accessKeyId: Credentials.AccessKeyId,
      secretAccessKey: Credentials.SecretAccessKey,
      sessionToken: Credentials.SessionToken,
    }
  } catch {
    console.log('using AWS SDK credential chain')
    return undefined
  }
}

const proxy = new S3Proxy({ bucket: BUCKET, credentials: getCredentials() })

try {
  await proxy.init()
  console.log(`S3Proxy initialized for bucket: ${BUCKET}`)
} catch (error) {
  console.error(`Failed to initialize S3Proxy for bucket: ${BUCKET}`, error)
  process.exit(1)
}

proxy.on('error', (error) => {
  console.error('S3Proxy error:', error)
})

const app = new Hono()

// Liveness + S3 connectivity. healthCheck() throws if the bucket is unreachable.
app.get('/health', async (c) => {
  await proxy.healthCheck()
  return c.json({ status: 'ok', timestamp: new Date().toISOString() })
})

app.get('/version', (c) =>
  c.json({
    s3proxy: S3PROXY_VERSION,
    node: process.version,
    timestamp: new Date().toISOString(),
  })
)

app.get('/', (c) => c.redirect('/index.html', 301))

// Stream every key straight from S3. fetchWeb() (s3proxy >= 4.2) adapts the Web
// Request → Response and throws a typed S3ProxyError on classified failures
// (404/403/416), which is handled by app.onError below.
app.on(['GET', 'HEAD'], '/*', (c) => proxy.fetchWeb(c.req.raw))

// Render errors as XML, matching the s3proxy Express/Fastify examples.
app.onError((error, c) => {
  const status = error.statusCode || 500
  const code = error.code || error.name || 'InternalError'
  if (status >= 500) {
    console.error(`${c.req.method} ${c.req.url} failed:`, error)
  } else {
    console.log(`${c.req.method} ${c.req.url} -> ${status} ${code}`)
  }
  const xml = `<?xml version="1.0"?>\n<error code="${code}" statusCode="${status}">${error.message}</error>`
  return new Response(xml, { status, headers: { 'content-type': 'application/xml' } })
})

const server = serve({ fetch: app.fetch, port: PORT, hostname: '0.0.0.0' }, ({ port }) => {
  console.log(`🚀 S3Proxy Hono server listening on port ${port}`)
  console.log(`📦 s3proxy version: ${S3PROXY_VERSION}`)
  console.log(`🪣 S3 bucket: ${BUCKET}`)
})

// Graceful shutdown for container stop / orchestrator signals.
const shutdown = (signal) => {
  console.log(`Received ${signal}, shutting down gracefully...`)
  server.close(() => process.exit(0))
}
process.on('SIGTERM', () => shutdown('SIGTERM'))
process.on('SIGINT', () => shutdown('SIGINT'))

export default app