@classmethod

    def get_by_repo_name(cls, repo_name):

        return cls.query().filter(cls.cache_args == repo_name).all()

    @classmethod

    def _get_or_create_key(cls, key, repo_name, commit=True):

        inv_obj = Session().query(cls).filter(cls.cache_key == key).scalar()

        if not inv_obj:

            try:

                inv_obj = CacheInvalidation(key, repo_name)

                Session().add(inv_obj)

                if commit:

                    Session().commit()

            except Exception:

                log.error(traceback.format_exc())

                Session().rollback()

        return inv_obj

    @classmethod

    def invalidate(cls, key):

        """

        Returns Invalidation object if this given key should be invalidated

        None otherwise. `cache_active = False` means that this cache

        state is not valid and needs to be invalidated

        :param key:

        """

        repo_name = key

        repo_name = remove_suffix(repo_name, '_README')

        repo_name = remove_suffix(repo_name, '_RSS')

        repo_name = remove_suffix(repo_name, '_ATOM')

        # adds instance prefix

        key, _prefix, _org_key = cls._get_key(key)

        inv = cls._get_or_create_key(key, repo_name)

        if inv and inv.cache_active is False:

            return inv

    @classmethod

    def set_invalidate(cls, key=None, repo_name=None):

        """

        Mark this Cache key for invalidation, either by key or whole

        cache sets based on repo_name

        :param key:

        """

        if key:

            key, _prefix, _org_key = cls._get_key(key)

            inv_objs = Session().query(cls).filter(cls.cache_key == key).all()

        elif repo_name:

            inv_objs = Session().query(cls).filter(cls.cache_args == repo_name).all()

        try:

            for inv_obj in inv_objs:

                inv_obj.cache_active = False

                Session().add(inv_obj)

            Session().commit()

        except Exception:

            log.error(traceback.format_exc())

            Session().rollback()

    @classmethod

    def set_valid(cls, key):

        """

        Mark this cache key as active and currently cached

        :param key:

        """

        inv_obj = cls.get_by_key(key)

        inv_obj.cache_active = True

        Session().add(inv_obj)

        Session().commit()

    @classmethod

    def get_cache_map(cls):

        class cachemapdict(dict):

            def __init__(self, *args, **kwargs):

                fixkey = kwargs.get('fixkey')

                if fixkey:

                    del kwargs['fixkey']

                self.fixkey = fixkey

                super(cachemapdict, self).__init__(*args, **kwargs)

            def __getattr__(self, name):

                key = name

                if self.fixkey:

                    key, _prefix, _org_key = cls._get_key(key)

                if key in self.__dict__:

                    return self.__dict__[key]

                else:

                    return self[key]

            def __getitem__(self, key):

                if self.fixkey:

                    key, _prefix, _org_key = cls._get_key(key)

                try:

                    return super(cachemapdict, self).__getitem__(key)

                except KeyError:

                    return

        cache_map = cachemapdict(fixkey=True)

        for obj in cls.query().all():

            cache_map[obj.cache_key] = cachemapdict(obj.get_dict())

        return cache_map

                    if path[0] == 'git' and path[0] in BACKENDS.keys():

                        repos[name] = klass(path[1])

            except OSError:

                continue

        log.debug('found %s paths with repositories' % (len(repos)))

        return repos

    def get_repos(self, all_repos=None, sort_key=None, simple=False):

        """

        Get all repos from db and for each repo create it's

        backend instance and fill that backed with information from database

        :param all_repos: list of repository names as strings

            give specific repositories list, good for filtering

        :param sort_key: initial sorting of repos

        :param simple: use SimpleCachedList - one without the SCM info

        """

        if all_repos is None:

            all_repos = self.sa.query(Repository)\

                        .filter(Repository.group_id == None)\

                        .order_by(func.lower(Repository.repo_name)).all()

        if simple:

            repo_iter = SimpleCachedRepoList(all_repos,

                                             repos_path=self.repos_path,

                                             order_by=sort_key)

        else:

            repo_iter = CachedRepoList(all_repos,

                                       repos_path=self.repos_path,

                                       order_by=sort_key)

        return repo_iter

    def get_repos_groups(self, all_groups=None):

        if all_groups is None:

            all_groups = RepoGroup.query()\

                .filter(RepoGroup.group_parent_id == None).all()

        group_iter = GroupList(all_groups)

        return group_iter

    def mark_for_invalidation(self, repo_name):

        """

        Puts cache invalidation task into db for

        further global cache invalidation

        :param repo_name: this repo that should invalidation take place

        """

        repo = Repository.get_by_repo_name(repo_name)

        if repo:

            repo.update_changeset_cache()

    def toggle_following_repo(self, follow_repo_id, user_id):

        f = self.sa.query(UserFollowing)\

            .filter(UserFollowing.follows_repo_id == follow_repo_id)\

            .filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                self.sa.delete(f)

                action_logger(UserTemp(user_id),

                              'stopped_following_repo',

                              RepoTemp(follow_repo_id))

                return

            except:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_repo_id = follow_repo_id

            self.sa.add(f)

            action_logger(UserTemp(user_id),

                          'started_following_repo',

                          RepoTemp(follow_repo_id))

        except:

            log.error(traceback.format_exc())

            raise

    def toggle_following_user(self, follow_user_id, user_id):

        f = self.sa.query(UserFollowing)\

            .filter(UserFollowing.follows_user_id == follow_user_id)\

            .filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                self.sa.delete(f)

                return

            except:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_user_id = follow_user_id