Write a manifest of the whole output

How to do it

Write the manifest as the last build step, outside the output folder, so it does not list itself. Use forward slashes in paths and sort by byte order, so every machine writes the same file. Store it next to the release, as the one-step deploy stores each release in its own folder. A server that renders pages on request gets the same kind of manifest from the live comparison.

Examples

Using these examples: they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

JavaScript example

import { createHash } from 'node:crypto'
import { readdirSync, readFileSync, writeFileSync } from 'node:fs'
import { join, relative, sep } from 'node:path'

const files = readdirSync('dist', { recursive: true, withFileTypes: true })
  .filter(entry => entry.isFile())
  .map(entry => join(entry.parentPath, entry.name))
const manifest = files.map(file => {
  const bytes = readFileSync(file)
  return { path: relative('dist', file).split(sep).join('/'), size: bytes.length, sha256: createHash('sha256').update(bytes).digest('hex') }
}).sort((a, b) => (a.path < b.path ? -1 : 1))
writeFileSync('manifest.json', JSON.stringify(manifest, null, 2) + '\n')

Python example

import hashlib, json
from pathlib import Path

root = Path("dist")
manifest = sorted(
    ({"path": p.relative_to(root).as_posix(), "size": p.stat().st_size,
      "sha256": hashlib.sha256(p.read_bytes()).hexdigest()}
     for p in root.rglob("*") if p.is_file()),
    key=lambda entry: entry["path"].encode())
Path("manifest.json").write_text(json.dumps(manifest, indent=2) + "\n")

How to check

Every release folder holds a manifest. A test counts the files in the output and fails when the manifest lists a different number, or when its paths are not sorted.

Related rules

• Deploy in one step and roll back by itself in Engineering
• Compare the live system before and after each deploy in Testing
• Prove a refactor changes nothing in Testing