'GET /api/version
Return a description of the major version of Galaxy (e.g. 15.03).
:rtype:     dict
:returns:   dictionary with major version keyed on \'version_major\''

@expose_api_anonymous_and_sessionless
def version(self, trans, **kwds):

    extra = {}
    try:
        version_file = os.environ.get('GALAXY_VERSION_JSON_FILE', (self.app.container_finder.app_info.galaxy_root_dir + '/version.json'))
        with open(version_file, 'r') as f:
            extra = json.load(f)
    except Exception:
        pass
    return {'version_major': self.app.config.version_major, 'extra': extra}
