Function buildHandler

packages/rust/src/index.ts:35–191

(options: BuildOptions)

type RustEnv = Record<'RUSTFLAGS' | 'PATH', string>;

async function buildHandler(options: BuildOptions): Promise<BuildResultV3> {
  const BUILDER_DEBUG = Boolean(process.env.VERCEL_BUILDER_DEBUG ?? false);
  const isVercelBuild = Boolean(process.env.VERCEL_BUILD_IMAGE ?? false);

  const { files, entrypoint, workPath, config, meta, service } = options;

  // If we are not building on Vercel and we are not initiainted from `vercel dev`,
  // we are building for a prebuilt deployment, so we need to cross-compile
  const crossCompilationEnabled = !isVercelBuild && !meta?.isDev;

  if (crossCompilationEnabled && process.platform === 'win32') {
    throw new Error(
      'Production prebuilt deployments for @vercel/rust are not yet supported on Windows. Please use a Linux or macOS environment, or deploy directly on Vercel.'
    );
  }

  await installRustToolchain();

  debug('Creating file system');
  const downloadedFiles = await download(files, workPath, meta);
  const entryPath = downloadedFiles[entrypoint].fsPath;

  const HOME =
    process.platform === 'win32' ? assertEnv('USERPROFILE') : assertEnv('HOME');
  const PATH = assertEnv('PATH');

  const rustEnv: RustEnv = {
    PATH: `${path.join(HOME, '.cargo/bin')}${path.delimiter}${PATH}`,
    RUSTFLAGS: [process.env.RUSTFLAGS].filter(Boolean).join(' '),
  };

  const cargoWorkspace = await findCargoWorkspace({
    env: rustEnv,
    cwd: path.dirname(entryPath),
  });

  const binaryName = findBinaryName(cargoWorkspace, entryPath);
  const cargoBuildConfiguration =
    await findCargoBuildConfiguration(cargoWorkspace);

  await runUserScripts(workPath);

  const extraFiles = await gatherExtraFiles(config.includeFiles, workPath);

  const lambdaOptions = await getLambdaOptionsFromFunction({
    sourceFile: entrypoint,
    config,
  });

  const architecture = lambdaOptions?.architecture || 'x86_64';

  const buildVariant = meta?.isDev ? 'debug' : 'release';
  const buildTarget = cargoBuildConfiguration?.build.target ?? '';
  const targetTriple =
    architecture === 'x86_64'
      ? 'x86_64-unknown-linux-gnu'
      : 'aarch64-unknown-linux-gnu';