Function finalizeLambda

packages/build-utils/src/finalize-lambda.ts:96–199

(
  params: FinalizeLambdaParams
)

 * supportsResponseStreaming).
 */
export async function finalizeLambda(
  params: FinalizeLambdaParams
): Promise<FinalizeLambdaResult> {
  const {
    lambda,
    encryptedEnvFilename,
    encryptedEnvContent,
    bytecodeCachingOptions,
    forceStreamingRuntime,
    enableUncompressedLambdaSizeCheck,
    trace = defaultTrace,
    createZip: createZipOverride,
    validateZip,
  } = params;

  // 1. Encrypted env injection
  const encryptedEnv = getEncryptedEnv(
    encryptedEnvFilename,
    encryptedEnvContent
  );
  if (encryptedEnv) {
    const [envFilename, envFile] = encryptedEnv;
    lambda.zipBuffer = undefined;
    lambda.files = {
      ...lambda.files,
      [envFilename]: envFile,
    };
  }

  // 2. Uncompressed size collection
  let uncompressedBytes = 0;
  if (enableUncompressedLambdaSizeCheck) {
    if (lambda.files) {
      uncompressedBytes = await trace('collectUncompressedSize', () =>
        collectUncompressedSize(lambda.files ?? {})
      );
    }
  }

  // 3. ZIP creation (pluggable strategy)
  const zipTags: Record<string, string> = {
    fileCount: String(Object.keys(lambda.files ?? {}).length),
    uncompressedBytes: String(uncompressedBytes),
  };

  let zipResult: CreateZipResult;
  if (createZipOverride) {
    // Custom path (e.g. file-based): digest already computed by callback
    zipResult = await trace(
      'createZip',
      () => createZipOverride(lambda),
      zipTags
    );
  } else {
    // Default in-memory path: create buffer first, digest deferred to step 5
    const buffer =
      lambda.zipBuffer ||
      (await trace('createZip', () => lambda.createZip(), zipTags));