python/kubernetes/base/dynamic/resource.py

# Copyright 2019 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import copy
import yaml
from functools import partial

from pprint import pformat


class Resource(object):
    """ Represents an API resource type, containing the information required to build urls for requests """

    def __init__(self, prefix=None, group=None, api_version=None, kind=None,
                 namespaced=False, verbs=None, name=None, preferred=False, client=None,
                 singularName=None, shortNames=None, categories=None, subresources=None, **kwargs):

        if None in (api_version, kind, prefix):
            raise ValueError("At least prefix, kind, and api_version must be provided")

        self.prefix = prefix
        self.group = group
        self.api_version = api_version
        self.kind = kind
        self.namespaced = namespaced
        self.verbs = verbs
        self.name = name
        self.preferred = preferred
        self.client = client
        self.singular_name = singularName or (name[:-1] if name else "")
        self.short_names = shortNames
        self.categories = categories
        self.subresources = {
            k: Subresource(self, **v) for k, v in (subresources or {}).items()
        }

        self.extra_args = kwargs

    def to_dict(self):
        d = {
            '_type': 'Resource',
            'prefix': self.prefix,
            'group': self.group,
            'api_version': self.api_version,
            'kind': self.kind,
            'namespaced': self.namespaced,
            'verbs': self.verbs,
            'name': self.name,
            'preferred': self.preferred,
            'singularName': self.singular_name,
            'shortNames': self.short_names,
            'categories': self.categories,
            'subresources': {k: sr.to_dict() for k, sr in self.subresources.items()},
        }
        d.update(self.extra_args)
        return d

    @property
    def group_version(self):
        if self.group:
            return '{}/{}'.format(self.group, self.api_version)
        return self.api_version

    def __repr__(self):
        return '<{}({}/{})>'.format(self.__class__.__name__, self.group_version, self.name)

    @property
    def urls(self):
        full_prefix = '{}/{}'.format(self.prefix, self.group_version)
        resource_name = self.name.lower()
        return {
            'base': '/{}/{}'.format(full_prefix, resource_name),
            'namespaced_base': '/{}/namespaces/{{namespace}}/{}'.format(full_prefix, resource_name),
            'full': '/{}/{}/{{name}}'.format(full_prefix, resource_name),
            'namespaced_full': '/{}/namespaces/{{namespace}}/{}/{{name}}'.format(full_prefix, resource_name)
        }

    def path(self, name=None, namespace=None):
        url_type = []
        path_params = {}
        if self.namespaced and namespace:
            url_type.append('namespaced')
            path_params['namespace'] = namespace
        if name:
            url_type.append('full')
            path_params['name'] = name
        else:
            url_type.append('base')
        return self.urls['_'.join(url_type)].format(**path_params)

    def __getattr__(self, name):
        if name in self.subresources:
            return self.subresources[name]
        return partial(getattr(self.client, name), self)


class ResourceList(Resource):
    """ Represents a list of API objects """

    def __init__(self, client, group='', api_version='v1', base_kind='', kind=None, base_resource_lookup=None):
        self.client = client
        self.group = group
        self.api_version = api_version
        self.kind = kind or '{}List'.format(base_kind)
        self.base_kind = base_kind
        self.base_resource_lookup = base_resource_lookup
        self.__base_resource = None

    def base_resource(self):
        if self.__base_resource:
            return self.__base_resource
        elif self.base_resource_lookup:
            self.__base_resource = self.client.resources.get(**self.base_resource_lookup)
            return self.__base_resource
        elif self.base_kind:
            self.__base_resource = self.client.resources.get(group=self.group, api_version=self.api_version, kind=self.base_kind)
            return self.__base_resource
        return None

    def _items_to_resources(self, body):
        """ Takes a List body and return a dictionary with the following structure:
            {
                'api_version': str,
                'kind': str,
                'items': [{
                    'resource': Resource,
                    'name': str,
                    'namespace': str,
                }]
            }
        """
        if body is None:
            raise ValueError("You must provide a body when calling methods on a ResourceList")

        api_version = body['apiVersion']
        kind = body['kind']
        items = body.get('items')
        if not items:
            raise ValueError('The `items` field in the body must be populated when calling methods on a ResourceList')

        if self.kind != kind:
            raise ValueError('Methods on a {} must be called with a body containing the same kind. Receieved {} instead'.format(self.kind, kind))

        return {
            'api_version': api_version,
            'kind': kind,
            'items': [self._item_to_resource(item) for item in items]
        }

    def _item_to_resource(self, item):
        metadata = item.get('metadata', {})
        resource = self.base_resource()
        if not resource:
            api_version = item.get('apiVersion', self.api_version)
            kind = item.get('kind', self.base_kind)
            resource = self.client.resources.get(api_version=api_version, kind=kind)
        return {
            'resource': resource,
            'definition': item,
            'name': metadata.get('name'),
            'namespace': metadata.get('namespace')
        }

    def get(self, body, name=None, namespace=None, **kwargs):
        if name:
            raise ValueError('Operations on ResourceList objects do not support the `name` argument')
        resource_list = self._items_to_resources(body)
        response = copy.deepcopy(body)

        response['items'] = [
            item['resource'].get(name=item['name'], namespace=item['namespace'] or namespace, **kwargs).to_dict()
            for item in resource_list['items']
        ]
        return ResourceInstance(self, response)

    def delete(self, body, name=None, namespace=None, **kwargs):
        if name:
            raise ValueError('Operations on ResourceList objects do not support the `name` argument')
        resource_list = self._items_to_resources(body)
        response = copy.deepcopy(body)

        response['items'] = [
            item['resource'].delete(name=item['name'], namespace=item['namespace'] or namespace, **kwargs).to_dict()
            for item in resource_list['items']
        ]
        return ResourceInstance(self, response)

    def verb_mapper(self, verb, body, **kwargs):
        resource_list = self._items_to_resources(body)
        response = copy.deepcopy(body)
        response['items'] = [
            getattr(item['resource'], verb)(body=item['definition'], **kwargs).to_dict()
            for item in resource_list['items']
        ]
        return ResourceInstance(self, response)

    def create(self, *args, **kwargs):
        return self.verb_mapper('create', *args, **kwargs)

    def replace(self, *args, **kwargs):
        return self.verb_mapper('replace', *args, **kwargs)

    def patch(self, *args, **kwargs):
        return self.verb_mapper('patch', *args, **kwargs)

    def to_dict(self):
        return {
            '_type': 'ResourceList',
            'group': self.group,
            'api_version': self.api_version,
            'kind': self.kind,
            'base_kind': self.base_kind
        }

    def __getattr__(self, name):
        if self.base_resource():
            return getattr(self.base_resource(), name)
        return None


class Subresource(Resource):
    """ Represents a subresource of an API resource. This generally includes operations
        like scale, as well as status objects for an instantiated resource
    """

    def __init__(self, parent, **kwargs):
        self.parent = parent
        self.prefix = parent.prefix
        self.group = parent.group
        self.api_version = parent.api_version
        self.kind = kwargs.pop('kind')
        self.name = kwargs.pop('name')
        self.subresource = kwargs.pop('subresource', None) or self.name.split('/')[1]
        self.namespaced = kwargs.pop('namespaced', False)
        self.verbs = kwargs.pop('verbs', None)
        self.extra_args = kwargs

    #TODO(fabianvf): Determine proper way to handle differences between resources + subresources
    def create(self, body=None, name=None, namespace=None, **kwargs):
        name = name or body.get('metadata', {}).get('name')
        body = self.parent.client.serialize_body(body)
        if self.parent.namespaced:
            namespace = self.parent.client.ensure_namespace(self.parent, namespace, body)
        path = self.path(name=name, namespace=namespace)
        return self.parent.client.request('post', path, body=body, **kwargs)

    @property
    def urls(self):
        full_prefix = '{}/{}'.format(self.prefix, self.group_version)
        return {
            'full': '/{}/{}/{{name}}/{}'.format(full_prefix, self.parent.name, self.subresource),
            'namespaced_full': '/{}/namespaces/{{namespace}}/{}/{{name}}/{}'.format(full_prefix, self.parent.name, self.subresource)
        }

    def __getattr__(self, name):
        return partial(getattr(self.parent.client, name), self)

    def to_dict(self):
        d = {
            'kind': self.kind,
            'name': self.name,
            'subresource': self.subresource,
            'namespaced': self.namespaced,
            'verbs': self.verbs
        }
        d.update(self.extra_args)
        return d


class ResourceInstance(object):
    """ A parsed instance of an API resource. It exists solely to
        ease interaction with API objects by allowing attributes to
        be accessed with '.' notation.
    """

    def __init__(self, client, instance):
        self.client = client
        # If we have a list of resources, then set the apiVersion and kind of
        # each resource in 'items'
        kind = instance['kind']
        if kind.endswith('List') and 'items' in instance:
            kind = instance['kind'][:-4]
            for item in instance['items']:
                if 'apiVersion' not in item:
                    item['apiVersion'] = instance['apiVersion']
                if 'kind' not in item:
                    item['kind'] = kind

        self.attributes = self.__deserialize(instance)
        self.__initialised = True

    def __deserialize(self, field):
        if isinstance(field, dict):
            return ResourceField(params={
                k: self.__deserialize(v) for k, v in field.items()
            })
        elif isinstance(field, (list, tuple)):
            return [self.__deserialize(item) for item in field]
        else:
            return field

    def __serialize(self, field):
        if isinstance(field, ResourceField):
            return {
                k: self.__serialize(v) for k, v in field.__dict__.items()
            }
        elif isinstance(field, (list, tuple)):
            return [self.__serialize(item) for item in field]
        elif isinstance(field, ResourceInstance):
            return field.to_dict()
        else:
            return field

    def to_dict(self):
        return self.__serialize(self.attributes)

    def to_str(self):
        return repr(self)

    def __repr__(self):
        return "ResourceInstance[{}]:\n  {}".format(
            self.attributes.kind,
            '  '.join(yaml.safe_dump(self.to_dict()).splitlines(True))
        )

    def __getattr__(self, name):
        if not '_ResourceInstance__initialised' in self.__dict__:
            return super(ResourceInstance, self).__getattr__(name)
        return getattr(self.attributes, name)

    def __setattr__(self, name, value):
        if not '_ResourceInstance__initialised' in self.__dict__:
            return super(ResourceInstance, self).__setattr__(name, value)
        elif name in self.__dict__:
            return super(ResourceInstance, self).__setattr__(name, value)
        else:
            self.attributes[name] = value

    def __getitem__(self, name):
        return self.attributes[name]

    def __setitem__(self, name, value):
        self.attributes[name] = value

    def __dir__(self):
        return dir(type(self)) + list(self.attributes.__dict__.keys())


class ResourceField(object):
    """ A parsed instance of an API resource attribute. It exists
        solely to ease interaction with API objects by allowing
        attributes to be accessed with '.' notation
    """

    def __init__(self, params):
        self.__dict__.update(**params)

    def __repr__(self):
        return pformat(self.__dict__)

    def __eq__(self, other):
        return self.__dict__ == other.__dict__

    def __getitem__(self, name):
        return self.__dict__.get(name)

    # Here resource.items will return items if available or resource.__dict__.items function if not
    # resource.get will call resource.__dict__.get after attempting resource.__dict__.get('get')
    def __getattr__(self, name):
        return self.__dict__.get(name, getattr(self.__dict__, name, None))

    def __setattr__(self, name, value):
        self.__dict__[name] = value

    def __dir__(self):
        return dir(type(self)) + list(self.__dict__.keys())

    def __iter__(self):
        for k, v in self.__dict__.items():
            yield (k, v)