Python yaml 模块，add_representer() 实例源码

def _dump_yaml(applied):
        """
        Dumps dict correctly processing multiline pre & postDescription string
        :param applied: dict -> filled config ready to be converted to yaml
        :return: str -> yaml config
        """

        def str_presenter(dumper, data):
            # check for multiline strings
            if len(data.splitlines()) == 1 and data[-1] == '\n':
                return dumper.represent_scalar(
                    'tag:yaml.org,2002:str', data, style='>')
            if len(data.splitlines()) > 1:
                return dumper.represent_scalar(
                    'tag:yaml.org,2002:str', data, style='|')
            return dumper.represent_scalar(
                'tag:yaml.org,2002:str', data.strip())

        yaml.add_representer(unicode, str_presenter)
        yaml.add_representer(str, str_presenter)
        return yaml.dump(applied, default_flow_style=False, width=1000)

def device_add(device, mgmt, role, network, username, password):
    device_conf = device + '.yaml'
    print device_conf
    device_dir = inv_dir + device + '/'
    print device_dir
    directory = os.path.dirname(device_dir) + '/'
    print directory
    if not os.path.exists(directory):
        os.makedirs(directory)
    target_dict = defaultdict(dict)
    target_dict[device]['name'] = device
    target_dict[device]['mgmt_ip'] = mgmt_ip
    target_dict[device]['role'] = role
    target_dict[device]['network'] = network
    target_dict[device]['username'] = username
    target_dict[device]['password'] = password

    with open(directory + device_conf, 'w') as outfile:
        yaml.add_representer(defaultdict, Representer.represent_dict)
        yaml.dump(target_dict, outfile, default_flow_style=False)
        return device + ' config added to inventory'

def configure_yml(self):

        def represent_ordereddict(dumper, data):
            value = []

            for item_key, item_value in data.items():
                node_key = dumper.represent_data(item_key)
                node_value = dumper.represent_data(item_value)

                value.append((node_key, node_value))

            return yaml.nodes.MappingNode(u'tag:yaml.org,2002:map', value)

        self.collect_answers()
        cfg = self.process_answers()

        yaml.add_representer(OrderedDict, represent_ordereddict)
        return yaml.dump(cfg, default_flow_style=False)

def get_yaml(self, restrict_to_fields=ZettelFieldsOrdered):
        yaml.add_representer(quoted, quoted_presenter)
        yaml.add_representer(literal, str_presenter)
        yaml.add_representer(OrderedDict, ordered_dict_presenter)
        parse_zettel(self.zettel)
        yaml_zettel = OrderedDict()
        for key in ZettelFields:
            if key not in self.zettel:
                continue
            if key not in restrict_to_fields:
                continue
            if key in ZettelStringFields:
                yaml_zettel[key] = literal(self.zettel[key])
            else:
                yaml_zettel[key] = self.zettel[key].copy()
        return yaml.dump(yaml_zettel, default_flow_style=False)

def __init__(self, full):
    super(YamlOutput, self).__init__(full)

    yaml.add_representer(unicode, self.string_presenter)
    yaml.add_representer(str, self.string_presenter)

def _install_customer_representers():
    """ Installs custom yaml representers so that yaml.dump() can use print out our custom classes like
    LineStr, LineDict, LineList """

    # TODO(jroovers): we need to support different yaml types like Float, Int, etc so that we don't print
    # everything like a string (i.e. wrap atomic type in quotes)

    def linestr_representer(dumper, data):
        node = dumper.represent_str(str(data))
        # If the linestring was entered as a string starting with |, we want to print it in the | again, because
        # otherwise pyyaml will insert too many newlines
        if hasattr(data, 'style') and '|' == data.style:
            node.style = data.style
        return node

    def lineint_representer(dumper, data):
        return dumper.represent_int(data)

    def linefloat_representer(dumper, data):
        return dumper.represent_float(data)

    def linedict_representer(dumper, data):
        return dumper.represent_dict(data)

    def linelist_representer(dumper, data):
        return dumper.represent_list(data)

    yaml.add_representer(LineInt, lineint_representer)
    yaml.add_representer(LineFloat, linefloat_representer)
    yaml.add_representer(LineStr, linestr_representer)
    yaml.add_representer(LineDict, linedict_representer)
    yaml.add_representer(LineList, linelist_representer)

def setup_yaml():
    """ http://stackoverflow.com/a/8661021 """
    represent_dict_order = lambda self, data: self.represent_mapping(
        'tag:yaml.org,2002:map', data.items())
    yaml.add_representer(collections.OrderedDict, represent_dict_order)

def write_content(self, content=None):
        if content:
            self.content = content
        self.__documents[self.__document_id] = self.content

        def representer(dumper, data):
            """Represents a dict key started with '!' as a YAML tag

            Assumes that there is only one !tag in the dict at the
            current indent.

            Python object:
            {"!unknown_tag": ["some content", ]}

            Resulting yaml:
            !unknown_tag
            - some content
            """
            key = data.keys()[0]
            if key.startswith("!"):
                value = data[key]
                if type(value) is dict:
                    node = dumper.represent_mapping(key, value)
                elif type(value) is list:
                    node = dumper.represent_sequence(key, value)
                else:
                    node = dumper.represent_scalar(key, value)
            else:
                node = dumper.represent_mapping(u'tag:yaml.org,2002:map', data)
            return node

        yaml.add_representer(dict, representer)
        with self.__get_file("w") as file_obj:
            yaml.dump_all(self.__documents, file_obj,
                          default_flow_style=self.default_flow_style,
                          default_style=self.default_style)

def dump(self):
        dumpdata = {}
        dumpdata['hosts']       = self.dump_hosts()
        dumpdata['hostgroup']   = self.dump_hostgroups()
        dumpdata['architecture'] = self.dump_arch()
        dumpdata['environment']  = self.dump_env()
        dumpdata['os']           = self.dump_os()
        dumpdata['model']        = self.dump_model()
        dumpdata['media']        = self.dump_media()
        dumpdata['domain']       = self.dump_domain()
        dumpdata['settings']     = self.dump_settings()
        dumpdata['subnet']       = self.dump_subnet()
        dumpdata['smart-proxy']  = self.dump_smartproxy()
        dumpdata['partition-table']  = self.dump_ptable()
        dumpdata['provisioning-template']  = self.dump_provisioningtpl()
        dumpdata['users']        = self.dump_users()
        dumpdata['users']        = self.dump_users()
        dumpdata['auth-source-ldap'] = self.dump_ldaps()
        dumpdata['usergroups'] = self.dump_usergroups()
        dumpdata['roles'] = self.dump_roles()

        # print the result
        fmyml = { 'foreman': dumpdata }

        def str_presenter(dumper, data):
            try:
                dlen = len(data.splitlines())
            except TypeError:
                return dumper.represent_scalar('tag:yaml.org,2002:str', data)
            if (dlen > 1):
                return dumper.represent_scalar('tag:yaml.org,2002:str', data, style='|')

            return dumper.represent_scalar('tag:yaml.org,2002:str', data)

        yaml.add_representer(unicode, str_presenter)
        yaml.add_representer(str, str_presenter)

        yml = yaml.dump(fmyml, allow_unicode=True, default_flow_style=False )
        print( (yml) )

def load_ordered_config(config_path):
    """
      Loads the configuration in the same order as it's defined in yaml file,
      so that, while saving it in new format, order is maintained
      Args:
            config_path (str): Path to the configuration file
      Returns:
            config(dict): Returns the configurations in the defined ordered
    """

    #  To load data from yaml in ordered dict format
    _mapping_tag = yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG

    def dict_representer(dumper, data):
        return dumper.represent_mapping(_mapping_tag, data.iteritems())

    def dict_constructor(loader, node):
        return collections.OrderedDict(loader.construct_pairs(node))

    yaml.add_representer(collections.OrderedDict, dict_representer)
    yaml.add_constructor(_mapping_tag, dict_constructor)

    #  format the output to print a blank scalar rather than null
    def represent_none(self, _):
        return self.represent_scalar('tag:yaml.org,2002:null', u'')

    yaml.add_representer(type(None), represent_none)

    # read input from home directory for pull requests
    with open(config_path, 'r') as f:
        config = yaml.load(f)
    return config

def read(self):
        # ensure yaml uses a defaultdict(str)
        yaml.add_representer(collections.defaultdict,
                             Representer.represent_str)
        try:
            with open(os.path.expanduser(self.path), 'r') as fh:
                self.conf = yaml.load(fh)
        except Exception as ex:
            logger.error("Unable to read config (%s): %s" % (self.path, ex))
            sys.exit(1)

def _readConfig():
    # ensure yaml uses a defaultdict(str)
    yaml.add_representer(collections.defaultdict,
                         Representer.represent_str)
    try:
        with open(os.path.expanduser(ConfigBase.path), 'r') as fh:
            config = yaml.load(fh)
    except Exception as ex:
        logger.error("Unable to read config (%s): %s" % (ConfigBase.path, ex))
        sys.exit(1)

    return config

def __init__(self, **options):
        super(YamlReaderWriter, self).__init__(**options)

        try:
            import yaml
            import yaml.resolver
        except ImportError:
            raise RuntimeError('To use YAML, please install PyYAML first')

        #
        # The code to preserve order of items is taken from here:
        # https://stackoverflow.com/a/21048064/38611
        #

        _mapping_tag = yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG

        def dict_representer(dumper, data):
            return dumper.represent_dict(data.items())

        def dict_constructor(loader, node):
            return collections.OrderedDict(loader.construct_pairs(node))

        yaml.add_representer(collections.OrderedDict, dict_representer)
        yaml.add_constructor(_mapping_tag, dict_constructor)

        self.yaml = yaml

        self.default_dump_options = {
            'indent': 2,
            'default_flow_style': False,
        }

def _dict_representer(dumper, data):
    return dumper.represent_dict(data.items())

#yaml.add_representer(recdefaultdict, _dict_representer)

def _init_yaml_ordereddict():
    def ordered_dict_presenter(dumper, data):
        return dumper.represent_dict(data.items())
    yaml.add_representer(collections.OrderedDict, ordered_dict_presenter)

def write_content(self, content=None):
        if content:
            self.content = content
        self.__documents[self.__document_id] = self.content

        def representer(dumper, data):
            """Represents a dict key started with '!' as a YAML tag

            Assumes that there is only one !tag in the dict at the
            current indent.

            Python object:
            {"!unknown_tag": ["some content", ]}

            Resulting yaml:
            !unknown_tag
            - some content
            """
            key = data.keys()[0]
            if key.startswith("!"):
                value = data[key]
                if type(value) is dict:
                    node = dumper.represent_mapping(key, value)
                elif type(value) is list:
                    node = dumper.represent_sequence(key, value)
                else:
                    node = dumper.represent_scalar(key, value)
            else:
                node = dumper.represent_mapping(u'tag:yaml.org,2002:map', data)
            return node

        yaml.add_representer(dict, representer)
        with self.__get_file("w") as file_obj:
            yaml.dump_all(self.__documents, file_obj,
                          default_flow_style=self.default_flow_style,
                          default_style=self.default_style)

def ordered_dump(data, stream=None, Dumper=yaml.Dumper, **kwds):
    # ordered_dump(data, Dumper=yaml.SafeDumper)
    class OrderedDumper(Dumper):
        pass
    def _dict_representer(dumper, data):
        return dumper.represent_mapping(
            yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG,
            data.items())
    OrderedDumper.add_representer(OrderedDict, _dict_representer)
    return yaml.dump(data, stream, OrderedDumper, **kwds)

def dump(self, ser_obj):
    if not self.representers_added:
      for SerializableChild in Serializable.__subclasses__():
        yaml.add_representer(SerializableChild, self.init_representer)
      self.representers_added = True
    return yaml.dump(ser_obj)

def arrow_representer(dumper, data):
  """Represent an `arrow.arrow.Arrow` object as a scalar in ISO format.

  >>> yaml.add_representer(arrow.arrow.Arrow, arrow_representer)
  >>> yaml.dump(arrow.get(1367900664))
  "! '2013-05-07T04:24:24+00:00'\\n"

  """
  return dumper.represent_scalar(u'!', six.text_type(data.isoformat(b'T' if six.PY2 else 'T')))

def main():
  parser = argparse.ArgumentParser(
    description="""Pull records for a batch of users and submit to external services."""
  )
  parser.add_argument('--timeout', dest="timeout", type=int, default=10)
  parser.add_argument('--limit', dest="limit", type=int, default=10,
      help="""Retrieve data for at most this many users concurrently.""")

  parser.add_argument('--log-file', dest='logfile', default='batch.log')

  parser.add_argument('input', nargs='?', type=argparse.FileType('r'), default=None)

  parser.add_argument('--collect-only', dest="collect_only", action="store_true")
  parser.add_argument('--debug', dest="debug", action="store_true", default=False)

  config = stethoscope.api.factory.get_config()
  args = parser.parse_args()

  for plugin in ['BITFIT', 'JAMF']:
    config[plugin + '_TIMEOUT'] = args.timeout

  config['LOGBOOK'] = stethoscope.utils.setup_logbook(args.logfile)
  config['LOGBOOK'].push_application()

  config['DEBUG'] = args.debug
  config['TESTING'] = args.debug

  yaml.add_representer(arrow.arrow.Arrow, arrow_representer)
  yaml.SafeDumper.add_representer(arrow.arrow.Arrow, arrow_representer)

  task.react(_main, (args, config))

def setup_yaml():
    _mapping_tag = yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG
    yaml.add_representer(collections.OrderedDict, dict_representer)
    yaml.add_representer(os._Environ, dict_representer)
    yaml.add_constructor(_mapping_tag, dict_constructor)

def dict_as_yaml(data):
    yaml.add_representer(quoted, quoted_presenter)
    yaml.add_representer(literal, str_presenter)
    yaml.add_representer(OrderedDict, ordered_dict_presenter)
    presented_data = OrderedDict()
    for key in data:
        presented_data[key] = data[key]
    return yaml.dump(presented_data, default_flow_style=False)

def register_yaml_representer():
    # Register our custom representer for YAML output
    yaml.add_representer(OrderedDict, represent_ordereddict)


# Custom representer for getting clean YAML output that preserves the order in
# an OrderedDict.
# Inspired by:
# http://stackoverflow.com/a/16782282/7169408

def setup_yaml():
    """Set YAML to use OrderedDict
    http://stackoverflow.com/a/8661021"""
    represent_dict_order = lambda self, data: self.represent_mapping(  # noqa
        'tag:yaml.org,2002:map', data.items()
    )
    yaml.add_representer(OrderedDict, represent_dict_order)

def main():
    """Main application entry point."""
    if len(sys.argv) != 2:
        print "Usage: yamlcalc <input-file>"
        return

    mapping_tag = yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG
    sequence_tag = yaml.resolver.BaseResolver.DEFAULT_SEQUENCE_TAG

    yaml.add_constructor(mapping_tag, dict_constructor)
    yaml.add_constructor(sequence_tag, list_constructor)
    yaml.add_representer(CalcDict, dict_representer)
    yaml.add_representer(CalcList, list_representer)

    try:
        with open(sys.argv[1]) as infp:
            top = yaml.load(infp)

            if not isinstance(top, CalcDict):
                type_name = type(top).__name__
                err("Top level element should be dict not {0}".format(type_name))

            defs = {}
            defs_str = top.get("DEFS", "")

            try:
                exec defs_str in defs
            except Exception as exc:
                err("Error executing DEFS: {0}".format(exc))

            CalcContainer.set_top(defs, top)

            view = top.get("VIEW", {})
            writer_type = view.get("type", "raw")
            writer_func_name = "_".join(writer_type.split("-"))

            try:
                write = globals()["write_" + writer_func_name]
            except KeyError:
                err("Error unsupporter writer: {0}".format(writer_type))

            outdir, ext = os.path.splitext(sys.argv[1])
            if os.path.exists(outdir):
                if not os.path.isdir(outdir):
                    err("Path exists but is not a directory: {0}".format(outdir))
            else:
                try:
                    os.mkdir(outdir)
                except OSError as exc:
                    err("Error create directory: {0}".format(outdir))

            write(view, top, outdir)
    except IOError as exc:
        err("Error opening file: {0}".format(exc))
    except yaml.YAMLError as exc:
        err("Error parsing input: {0}".format(exc))

def juju_state_to_yaml(yaml_path, namespace_separator=':',
                       allow_hyphens_in_keys=True, mode=None):
    """Update the juju config and state in a yaml file.

    This includes any current relation-get data, and the charm
    directory.

    This function was created for the ansible and saltstack
    support, as those libraries can use a yaml file to supply
    context to templates, but it may be useful generally to
    create and update an on-disk cache of all the config, including
    previous relation data.

    By default, hyphens are allowed in keys as this is supported
    by yaml, but for tools like ansible, hyphens are not valid [1].

    [1] http://www.ansibleworks.com/docs/playbooks_variables.html#what-makes-a-valid-variable-name
    """
    config = charmhelpers.core.hookenv.config()

    # Add the charm_dir which we will need to refer to charm
    # file resources etc.
    config['charm_dir'] = charm_dir
    config['local_unit'] = charmhelpers.core.hookenv.local_unit()
    config['unit_private_address'] = charmhelpers.core.hookenv.unit_private_ip()
    config['unit_public_address'] = charmhelpers.core.hookenv.unit_get(
        'public-address'
    )

    # Don't use non-standard tags for unicode which will not
    # work when salt uses yaml.load_safe.
    yaml.add_representer(six.text_type,
                         lambda dumper, value: dumper.represent_scalar(
                             six.u('tag:yaml.org,2002:str'), value))

    yaml_dir = os.path.dirname(yaml_path)
    if not os.path.exists(yaml_dir):
        os.makedirs(yaml_dir)

    if os.path.exists(yaml_path):
        with open(yaml_path, "r") as existing_vars_file:
            existing_vars = yaml.load(existing_vars_file.read())
    else:
        with open(yaml_path, "w+"):
            pass
        existing_vars = {}

    if mode is not None:
        os.chmod(yaml_path, mode)

    if not allow_hyphens_in_keys:
        config = dict_keys_without_hyphens(config)
    existing_vars.update(config)

    update_relations(existing_vars, namespace_separator)

    with open(yaml_path, "w+") as fp:
        fp.write(yaml.dump(existing_vars, default_flow_style=False))