func GetFilterFromFilterPolicy()

in internal/cssc/cssc.go [73:120]
42 lines of code
8 McCabe index (conditional complexity)

func GetFilterFromFilterPolicy(ctx context.Context, filterPolicy string, loginURL string, username string, password string) (Filter, error) {
	filterPolicyPattern := `^[^:]+:[^:]+$`
	re := regexp.MustCompile(filterPolicyPattern)
	if !re.MatchString(filterPolicy) {
		return Filter{}, errors.New("filter-policy should be in the format repository:tag e.g. continuouspatchpolicy:latest")
	}
	repoTag := strings.Split(filterPolicy, ":")
	filterRepoName := repoTag[0]
	filterRepoTagName := repoTag[1]

	// Connect to the remote repository
	repo, err := remote.NewRepository(fmt.Sprintf("%s/%s", loginURL, filterRepoName))
	if err != nil {
		return Filter{}, errors.Wrap(err, "error connecting to the repository when reading the filter policy")
	}
	repo.Client = &auth.Client{
		Client: retry.DefaultClient,
		Cache:  auth.NewCache(),
		Credential: auth.StaticCredential(loginURL, auth.Credential{
			Username: username,
			Password: password,
		}),
	}

	// Get manifest and read content
	_, pulledManifestContent, err := oras.FetchBytes(ctx, repo, filterRepoTagName, oras.DefaultFetchBytesOptions)
	if err != nil {
		return Filter{}, errors.Wrap(err, "error fetching filter manifest content when reading the filter policy")
	}
	var pulledManifest v1.Manifest
	if err := json.Unmarshal(pulledManifestContent, &pulledManifest); err != nil {
		return Filter{}, errors.Wrap(err, "error unmarshalling filter manifest content when reading the filter policy")
	}
	var fileContent []byte
	for _, layer := range pulledManifest.Layers {
		fileContent, err = content.FetchAll(ctx, repo, layer)
		if err != nil {
			return Filter{}, errors.Wrap(err, "error fetching filter content when reading the filter policy")
		}
	}

	// Unmarshal the JSON file data to Filter struct
	var filter = Filter{}
	if err := json.Unmarshal(fileContent, &filter); err != nil {
		return Filter{}, errors.Wrap(err, "error unmarshalling json content when reading the filter policy")
	}
	return filter, nil
}