def get_stream(self, name, force_refresh=False, serve_from_cache=False):
        uname, version = split_name(name)
        lock = None
        if self.local_store:
            lock = self.lock_manager.lock_for(uname)
            lock.lock_shared()
        try:
            if not self.remote_store or (version is not None
                                         and not force_refresh):
                try:
                    if self.local_store and self.local_store.exists(name):
                        return self.local_store.get_stream(name)
                except Exception:
                    if self.remote_store:
                        logger.warning("Error getting '%s' from local store",
                                       name, exc_info=True)
                    else:
                        raise
            if self.remote_store:
                if self.local_store and serve_from_cache:
                    if version is None:
                        version = self.remote_store.file_version(name)
                        if version:
                            name = versioned_name(uname, version)
                    if force_refresh or not self.local_store.exists(name):
                        (stream, vname) = self.remote_store.get_stream(name)
                        name = self.local_store.add_stream(vname, stream)
                    return self.local_store.get_stream(name)
                return self.remote_store.get_stream(name)
            raise FiletrackerError("File not available: %s" % name)
        finally:
            if lock:
                lock.close()