func()

in lambda/internal/tarfile/src.go [72:103]

• 27 lines of code
• 6 McCabe index (conditional complexity)

func (s *S3FileSource) ensureCachedDataIsPresentPrivate() error {
	tarManifest, _, err := s.s3fileReader.ChooseManifestItem(s.ref, s.sourceIndex)
	if err != nil {
		return err
	}

	// Read and parse config.
	configBytes, err := s.s3fileReader.readTarComponent(tarManifest.Config, iolimits.MaxConfigBodySize)
	if err != nil {
		return err
	}
	var parsedConfig manifest.Schema2Image // There's a lot of info there, but we only really care about layer DiffIDs.
	if err := json.Unmarshal(configBytes, &parsedConfig); err != nil {
		return errors.Wrapf(err, "Error decoding tar config %s", tarManifest.Config)
	}
	if parsedConfig.RootFS == nil {
		return errors.Errorf("Invalid image config (rootFS is not set): %s", tarManifest.Config)
	}

	knownLayers, err := s.prepareLayerData(tarManifest, &parsedConfig)
	if err != nil {
		return err
	}

	// Success; commit.
	s.tarManifest = tarManifest
	s.configBytes = configBytes
	s.configDigest = digest.FromBytes(configBytes)
	s.orderedDiffIDList = parsedConfig.RootFS.DiffIDs
	s.knownLayers = knownLayers
	return nil
}