Add basic client work + regions support

cratonclient/base.py

@@ -0,0 +1,536 @@
+# Copyright 2010 Jacob Kaplan-Moss
+# Copyright 2011 OpenStack Foundation
+# Copyright 2013 OpenStack Foundation
+# All Rights Reserved.
+#
+#    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.
+
+"""Base utilities to build API operation managers and objects on top of."""
+
+import abc
+import copy
+import functools
+import warnings
+
+from oslo_utils import strutils
+import six
+from six.moves import urllib
+
+from keystoneclient import auth
+from keystoneclient import exceptions
+from keystoneclient.i18n import _
+
+
+def getid(obj):
+    """Return id if argument is a Resource.
+
+    Abstracts the common pattern of allowing both an object or an object's ID
+    (UUID) as a parameter when dealing with relationships.
+    """
+    try:
+        if obj.uuid:
+            return obj.uuid
+    except AttributeError:  # nosec(cjschaef): 'obj' doesn't contain attribute
+        # 'uuid', return attribute 'id' or the 'obj'
+        pass
+    try:
+        return obj.id
+    except AttributeError:
+        return obj
+
+
+def filter_none(**kwargs):
+    """Remove any entries from a dictionary where the value is None."""
+    return dict((k, v) for k, v in six.iteritems(kwargs) if v is not None)
+
+
+def filter_kwargs(f):
+    @functools.wraps(f)
+    def func(*args, **kwargs):
+        new_kwargs = {}
+        for key, ref in six.iteritems(kwargs):
+            if ref is None:
+                # drop null values
+                continue
+
+            id_value = getid(ref)
+            if id_value != ref:
+                # If an object with an id was passed, then use the id, e.g.:
+                #     user: user(id=1) becomes user_id: 1
+                key = '%s_id' % key
+
+            new_kwargs[key] = id_value
+
+        return f(*args, **new_kwargs)
+    return func
+
+
+class Manager(object):
+    """Basic manager type providing common operations.
+
+    Managers interact with a particular type of API (servers, flavors, images,
+    etc.) and provide CRUD operations for them.
+
+    :param client: instance of BaseClient descendant for HTTP requests
+
+    """
+
+    resource_class = None
+
+    def __init__(self, client):
+        super(Manager, self).__init__()
+        self.client = client
+
+    @property
+    def api(self):
+        """The client.
+
+        .. warning::
+
+            This property is deprecated as of the 1.7.0 release in favor of
+            :meth:`client` and may be removed in the 2.0.0 release.
+
+        """
+        warnings.warn(
+            'api is deprecated as of the 1.7.0 release in favor of client and '
+            'may be removed in the 2.0.0 release', DeprecationWarning)
+        return self.client
+
+    def _list(self, url, response_key, obj_class=None, body=None, **kwargs):
+        """List the collection.
+
+        :param url: a partial URL, e.g., '/servers'
+        :param response_key: the key to be looked up in response dictionary,
+            e.g., 'servers'
+        :param obj_class: class for constructing the returned objects
+            (self.resource_class will be used by default)
+        :param body: data that will be encoded as JSON and passed in POST
+            request (GET will be sent by default)
+        :param kwargs: Additional arguments will be passed to the request.
+        """
+        if body:
+            resp, body = self.client.post(url, body=body, **kwargs)
+        else:
+            resp, body = self.client.get(url, **kwargs)
+
+        if obj_class is None:
+            obj_class = self.resource_class
+
+        data = body[response_key]
+        # NOTE(ja): keystone returns values as list as {'values': [ ... ]}
+        #           unlike other services which just return the list...
+        try:
+            data = data['values']
+        except (KeyError, TypeError):  # nosec(cjschaef): keystone data values
+            # not as expected (see comment above), assumption is that values
+            # are already returned in a list (so simply utilize that list)
+            pass
+
+        return [obj_class(self, res, loaded=True) for res in data if res]
+
+    def _get(self, url, response_key, **kwargs):
+        """Get an object from collection.
+
+        :param url: a partial URL, e.g., '/servers'
+        :param response_key: the key to be looked up in response dictionary,
+            e.g., 'server'
+        :param kwargs: Additional arguments will be passed to the request.
+        """
+        resp, body = self.client.get(url, **kwargs)
+        return self.resource_class(self, body[response_key], loaded=True)
+
+    def _head(self, url, **kwargs):
+        """Retrieve request headers for an object.
+
+        :param url: a partial URL, e.g., '/servers'
+        :param kwargs: Additional arguments will be passed to the request.
+        """
+        resp, body = self.client.head(url, **kwargs)
+        return resp.status_code == 204
+
+    def _post(self, url, body, response_key, return_raw=False, **kwargs):
+        """Create an object.
+
+        :param url: a partial URL, e.g., '/servers'
+        :param body: data that will be encoded as JSON and passed in POST
+            request (GET will be sent by default)
+        :param response_key: the key to be looked up in response dictionary,
+            e.g., 'servers'
+        :param return_raw: flag to force returning raw JSON instead of
+            Python object of self.resource_class
+        :param kwargs: Additional arguments will be passed to the request.
+        """
+        resp, body = self.client.post(url, body=body, **kwargs)
+        if return_raw:
+            return body[response_key]
+        return self.resource_class(self, body[response_key])
+
+    def _put(self, url, body=None, response_key=None, **kwargs):
+        """Update an object with PUT method.
+
+        :param url: a partial URL, e.g., '/servers'
+        :param body: data that will be encoded as JSON and passed in POST
+            request (GET will be sent by default)
+        :param response_key: the key to be looked up in response dictionary,
+            e.g., 'servers'
+        :param kwargs: Additional arguments will be passed to the request.
+        """
+        resp, body = self.client.put(url, body=body, **kwargs)
+        # PUT requests may not return a body
+        if body is not None:
+            if response_key is not None:
+                return self.resource_class(self, body[response_key])
+            else:
+                return self.resource_class(self, body)
+
+    def _patch(self, url, body=None, response_key=None, **kwargs):
+        """Update an object with PATCH method.
+
+        :param url: a partial URL, e.g., '/servers'
+        :param body: data that will be encoded as JSON and passed in POST
+            request (GET will be sent by default)
+        :param response_key: the key to be looked up in response dictionary,
+            e.g., 'servers'
+        :param kwargs: Additional arguments will be passed to the request.
+        """
+        resp, body = self.client.patch(url, body=body, **kwargs)
+        if response_key is not None:
+            return self.resource_class(self, body[response_key])
+        else:
+            return self.resource_class(self, body)
+
+    def _delete(self, url, **kwargs):
+        """Delete an object.
+
+        :param url: a partial URL, e.g., '/servers/my-server'
+        :param kwargs: Additional arguments will be passed to the request.
+        """
+        return self.client.delete(url, **kwargs)
+
+    def _update(self, url, body=None, response_key=None, method="PUT",
+                **kwargs):
+        methods = {"PUT": self.client.put,
+                   "POST": self.client.post,
+                   "PATCH": self.client.patch}
+        try:
+            resp, body = methods[method](url, body=body,
+                                         **kwargs)
+        except KeyError:
+            raise exceptions.ClientException(_("Invalid update method: %s")
+                                             % method)
+        # PUT requests may not return a body
+        if body:
+            return self.resource_class(self, body[response_key])
+
+
+@six.add_metaclass(abc.ABCMeta)
+class ManagerWithFind(Manager):
+    """Manager with additional `find()`/`findall()` methods."""
+
+    @abc.abstractmethod
+    def list(self):
+        pass  # pragma: no cover
+
+    def find(self, **kwargs):
+        """Find a single item with attributes matching ``**kwargs``.
+
+        This isn't very efficient: it loads the entire list then filters on
+        the Python side.
+        """
+        rl = self.findall(**kwargs)
+        num = len(rl)
+
+        if num == 0:
+            msg = _("No %(name)s matching %(kwargs)s.") % {
+                'name': self.resource_class.__name__, 'kwargs': kwargs}
+            raise exceptions.NotFound(404, msg)
+        elif num > 1:
+            raise exceptions.NoUniqueMatch
+        else:
+            return rl[0]
+
+    def findall(self, **kwargs):
+        """Find all items with attributes matching ``**kwargs``.
+
+        This isn't very efficient: it loads the entire list then filters on
+        the Python side.
+        """
+        found = []
+        searches = kwargs.items()
+
+        for obj in self.list():
+            try:
+                if all(getattr(obj, attr) == value
+                       for (attr, value) in searches):
+                    found.append(obj)
+            except AttributeError:
+                continue
+
+        return found
+
+
+class CrudManager(Manager):
+    """Base manager class for manipulating Keystone entities.
+
+    Children of this class are expected to define a `collection_key` and `key`.
+
+    - `collection_key`: Usually a plural noun by convention (e.g. `entities`);
+      used to refer collections in both URL's (e.g.  `/v3/entities`) and JSON
+      objects containing a list of member resources (e.g. `{'entities': [{},
+      {}, {}]}`).
+    - `key`: Usually a singular noun by convention (e.g. `entity`); used to
+      refer to an individual member of the collection.
+
+    """
+
+    collection_key = None
+    key = None
+    base_url = None
+
+    def build_url(self, dict_args_in_out=None):
+        """Build a resource URL for the given kwargs.
+
+        Given an example collection where `collection_key = 'entities'` and
+        `key = 'entity'`, the following URL's could be generated.
+
+        By default, the URL will represent a collection of entities, e.g.::
+
+            /entities
+
+        If kwargs contains an `entity_id`, then the URL will represent a
+        specific member, e.g.::
+
+            /entities/{entity_id}
+
+        If a `base_url` is provided, the generated URL will be appended to it.
+
+        If a 'tail' is provided, it will be appended to the end of the URL.
+
+        """
+        if dict_args_in_out is None:
+            dict_args_in_out = {}
+
+        url = dict_args_in_out.pop('base_url', None) or self.base_url or ''
+        url += '/%s' % self.collection_key
+
+        # do we have a specific entity?
+        entity_id = dict_args_in_out.pop('%s_id' % self.key, None)
+        if entity_id is not None:
+            url += '/%s' % entity_id
+
+        if dict_args_in_out.get('tail'):
+            url += dict_args_in_out['tail']
+
+        return url
+
+    @filter_kwargs
+    def create(self, **kwargs):
+        url = self.build_url(dict_args_in_out=kwargs)
+        return self._post(
+            url,
+            {self.key: kwargs},
+            self.key)
+
+    @filter_kwargs
+    def get(self, **kwargs):
+        return self._get(
+            self.build_url(dict_args_in_out=kwargs),
+            self.key)
+
+    @filter_kwargs
+    def head(self, **kwargs):
+        return self._head(self.build_url(dict_args_in_out=kwargs))
+
+    def _build_query(self, params):
+        return '?%s' % urllib.parse.urlencode(params) if params else ''
+
+    def build_key_only_query(self, params_list):
+        """Build a query that does not include values, just keys.
+
+        The Identity API has some calls that define queries without values,
+        this can not be accomplished by using urllib.parse.urlencode(). This
+        method builds a query using only the keys.
+        """
+        return '?%s' % '&'.join(params_list) if params_list else ''
+
+    @filter_kwargs
+    def list(self, fallback_to_auth=False, **kwargs):
+        if 'id' in kwargs.keys():
+            # Ensure that users are not trying to call things like
+            # ``domains.list(id='default')`` when they should have used
+            # ``[domains.get(domain_id='default')]`` instead. Keystone supports
+            # ``GET /v3/domains/{domain_id}``, not ``GET
+            # /v3/domains?id={domain_id}``.
+            raise TypeError(
+                _("list() got an unexpected keyword argument 'id'. To "
+                  "retrieve a single object using a globally unique "
+                  "identifier, try using get() instead."))
+
+        url = self.build_url(dict_args_in_out=kwargs)
+
+        try:
+            query = self._build_query(kwargs)
+            url_query = '%(url)s%(query)s' % {'url': url, 'query': query}
+            return self._list(
+                url_query,
+                self.collection_key)
+        except exceptions.EmptyCatalog:
+            if fallback_to_auth:
+                return self._list(
+                    url_query,
+                    self.collection_key,
+                    endpoint_filter={'interface': auth.AUTH_INTERFACE})
+            else:
+                raise
+
+    @filter_kwargs
+    def put(self, **kwargs):
+        return self._update(
+            self.build_url(dict_args_in_out=kwargs),
+            method='PUT')
+
+    @filter_kwargs
+    def update(self, **kwargs):
+        url = self.build_url(dict_args_in_out=kwargs)
+
+        return self._update(
+            url,
+            {self.key: kwargs},
+            self.key,
+            method='PATCH')
+
+    @filter_kwargs
+    def delete(self, **kwargs):
+        return self._delete(
+            self.build_url(dict_args_in_out=kwargs))
+
+    @filter_kwargs
+    def find(self, **kwargs):
+        """Find a single item with attributes matching ``**kwargs``."""
+        url = self.build_url(dict_args_in_out=kwargs)
+
+        query = self._build_query(kwargs)
+        rl = self._list(
+            '%(url)s%(query)s' % {
+                'url': url,
+                'query': query,
+            },
+            self.collection_key)
+        num = len(rl)
+
+        if num == 0:
+            msg = _("No %(name)s matching %(kwargs)s.") % {
+                'name': self.resource_class.__name__, 'kwargs': kwargs}
+            raise exceptions.NotFound(404, msg)
+        elif num > 1:
+            raise exceptions.NoUniqueMatch
+        else:
+            return rl[0]
+
+
+class Resource(object):
+    """Base class for OpenStack resources (tenant, user, etc.).
+
+    This is pretty much just a bag for attributes.
+    """
+
+    HUMAN_ID = False
+    NAME_ATTR = 'name'
+
+    def __init__(self, manager, info, loaded=False):
+        """Populate and bind to a manager.
+
+        :param manager: BaseManager object
+        :param info: dictionary representing resource attributes
+        :param loaded: prevent lazy-loading if set to True
+        """
+        self.manager = manager
+        self._info = info
+        self._add_details(info)
+        self._loaded = loaded
+
+    def __repr__(self):
+        """Return string representation of resource attributes."""
+        reprkeys = sorted(k
+                          for k in self.__dict__.keys()
+                          if k[0] != '_' and k != 'manager')
+        info = ", ".join("%s=%s" % (k, getattr(self, k)) for k in reprkeys)
+        return "<%s %s>" % (self.__class__.__name__, info)
+
+    @property
+    def human_id(self):
+        """Human-readable ID which can be used for bash completion."""
+        if self.HUMAN_ID:
+            name = getattr(self, self.NAME_ATTR, None)
+            if name is not None:
+                return strutils.to_slug(name)
+        return None
+
+    def _add_details(self, info):
+        for (k, v) in six.iteritems(info):
+            try:
+                setattr(self, k, v)
+                self._info[k] = v
+            except AttributeError:  # nosec(cjschaef): we already defined the
+                # attribute on the class
+                pass
+
+    def __getattr__(self, k):
+        """Checking attrbiute existence."""
+        if k not in self.__dict__:
+            # NOTE(bcwaldon): disallow lazy-loading if already loaded once
+            if not self.is_loaded():
+                self.get()
+                return self.__getattr__(k)
+
+            raise AttributeError(k)
+        else:
+            return self.__dict__[k]
+
+    def get(self):
+        """Support for lazy loading details.
+
+        Some clients, such as novaclient have the option to lazy load the
+        details, details which can be loaded with this function.
+        """
+        # set_loaded() first ... so if we have to bail, we know we tried.
+        self.set_loaded(True)
+        if not hasattr(self.manager, 'get'):
+            return
+
+        new = self.manager.get(self.id)
+        if new:
+            self._add_details(new._info)
+            self._add_details(
+                {'x_request_id': self.manager.client.last_request_id})
+
+    def __eq__(self, other):
+        """Define equality for resources."""
+        if not isinstance(other, Resource):
+            return NotImplemented
+        # two resources of different types are not equal
+        if not isinstance(other, self.__class__):
+            return False
+        return self._info == other._info
+
+    def is_loaded(self):
+        return self._loaded
+
+    def set_loaded(self, val):
+        self._loaded = val
+
+    def to_dict(self):
+        return copy.deepcopy(self._info)
+
+    def delete(self):
+        return self.manager.delete(self)

cratonclient/crud.py

@@ -0,0 +1,177 @@
+"""Client for CRUD operations."""
+
+class CRUDClient(object):
+    """Class that handles the basic create, read, upload, delete workflow."""
+
+    key = None
+    base_path = None
+    resource_class = None
+
+    def __init__(self, session, url):
+        self.session = session
+        self.url = url.rstrip('/')
+
+    def build_url(self, path_arguments=None):
+        """Build a complete URL from the url, base_path, and arguments.
+
+        A CRUDClient is constructed with the base URL, e.g.
+
+        .. code-block:: python
+
+            RegionManager(url='https://10.1.1.0:8080/v1', ...)
+
+        The child class of the CRUDClient may set the ``base_path``, e.g.,
+
+        .. code-block:: python
+            
+            base_path = '/regions'
+
+        And it's ``key``, e.g.,
+        
+        .. code-block:: python
+
+            key = 'region'
+
+        And based on the ``path_arguments`` parameter we will construct a
+        complete URL. For example, if someone calls:
+
+        .. code-block:: python
+
+            self.build_url(path_arguments={'region_id': 1})
+
+        with the hypothetical values above, we would return
+
+            https://10.1.1.0:8080/v1/regions/1
+
+        Users can also override ``base_path`` in ``path_arguments``.
+        """
+        if path_arguments is None:
+            path_arguments = {}
+
+        base_path = path_arguments.pop('base_path', None) or self.base_path
+        item_id = path_arguments.pop('{0}_id'.format(self.key), None)
+
+        url = self.url + base_path
+
+        if item_id is not None:
+            url += '/{0}'.format(item_id)
+
+        return url
+
+    def create(self, **kwargs):
+        """Create a new item based on the keyword arguments provided."""
+        url = self.build_url(path_arguments=kwargs)
+        response = self.session.post(url, json=kwargs)
+        return self.resource_class(self, response.json())
+
+    def get(self, **kwargs):
+        """Retrieve the item based on the keyword arguments provided."""
+        url = self.build_url(path_arguments=kwargs)
+        response = self.session.get(url)
+        return self.resource_class(self, response.json())
+
+    def list(self, **kwargs):
+        """List the items from this endpoint."""
+        url = self.build_url(path_arguments=kwargs)
+        response = self.session.get(url, params=kwargs)
+        return [self.resource_class(self, item) for item in response.json()]
+
+
+# NOTE(sigmavirus24): Credit for this Resource object goes to the
+# keystoneclient developers and contributors.
+class Resource(object):
+    """Base class for OpenStack resources (tenant, user, etc.).
+
+    This is pretty much just a bag for attributes.
+    """
+
+    HUMAN_ID = False
+    NAME_ATTR = 'name'
+
+    def __init__(self, manager, info, loaded=False):
+        """Populate and bind to a manager.
+
+        :param manager: BaseManager object
+        :param info: dictionary representing resource attributes
+        :param loaded: prevent lazy-loading if set to True
+        """
+        self.manager = manager
+        self._info = info
+        self._add_details(info)
+        self._loaded = loaded
+
+    def __repr__(self):
+        """Return string representation of resource attributes."""
+        reprkeys = sorted(k
+                          for k in self.__dict__.keys()
+                          if k[0] != '_' and k != 'manager')
+        info = ", ".join("%s=%s" % (k, getattr(self, k)) for k in reprkeys)
+        return "<%s %s>" % (self.__class__.__name__, info)
+
+    @property
+    def human_id(self):
+        """Human-readable ID which can be used for bash completion."""
+        if self.HUMAN_ID:
+            name = getattr(self, self.NAME_ATTR, None)
+            if name is not None:
+                return strutils.to_slug(name)
+        return None
+
+    def _add_details(self, info):
+        for (k, v) in info.items():
+            try:
+                setattr(self, k, v)
+                self._info[k] = v
+            except AttributeError:  # nosec(cjschaef): we already defined the
+                # attribute on the class
+                pass
+
+    def __getattr__(self, k):
+        """Checking attrbiute existence."""
+        if k not in self.__dict__:
+            # NOTE(bcwaldon): disallow lazy-loading if already loaded once
+            if not self.is_loaded():
+                self.get()
+                return self.__getattr__(k)
+
+            raise AttributeError(k)
+        else:
+            return self.__dict__[k]
+
+    def get(self):
+        """Support for lazy loading details.
+
+        Some clients, such as novaclient have the option to lazy load the
+        details, details which can be loaded with this function.
+        """
+        # set_loaded() first ... so if we have to bail, we know we tried.
+        self.set_loaded(True)
+        if not hasattr(self.manager, 'get'):
+            return
+
+        new = self.manager.get(self.id)
+        if new:
+            self._add_details(new._info)
+            self._add_details(
+                {'x_request_id': self.manager.client.last_request_id})
+
+    def __eq__(self, other):
+        """Define equality for resources."""
+        if not isinstance(other, Resource):
+            return NotImplemented
+        # two resources of different types are not equal
+        if not isinstance(other, self.__class__):
+            return False
+        return self._info == other._info
+
+    def is_loaded(self):
+        return self._loaded
+
+    def set_loaded(self, val):
+        self._loaded = val
+
+    def to_dict(self):
+        return copy.deepcopy(self._info)
+
+    def delete(self):
+        return self.manager.delete(self)

cratonclient/exceptions.py

@@ -0,0 +1,256 @@
+# -*- coding: utf-8 -*-
+
+# 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.
+"""Exception classes and logic for cratonclient."""
+
+class ClientException(Exception):
+    """Base exception class for all exceptions in cratonclient."""
+
+    message = None
+
+    def __init__(self, message=None):
+        """Initialize our exception instance with our class level message."""
+        if message is None:
+            if self.message is None:
+                message = self.__class__.__name__
+            else:
+                message = self.message
+        super(ClientException, self).__init__(message)
+
+
+class Timeout(ClientException):
+    """Catch-all class for connect and read timeouts from requests."""
+
+    message = 'Request timed out'
+    
+    def __init__(self, message=None, **kwargs):
+        self.original_exception = kwargs.pop('exception', None)
+        super(Timeout, self).__init__(message)
+
+
+class HTTPError(ClientException):
+    """Base exception class for all HTTP related exceptions in."""
+
+    message = "An error occurred while talking to the remote server."
+    status_code = None
+
+    def __init__(self, message=None, **kwargs):
+        self.response = kwargs.pop('response', None)
+        self.original_exception = kwargs.pop('exception', None)
+        self.status_code = (self.status_code
+                            or getattr(self.response, 'status_code', None))
+        super(HTTPError, self).__init__(message)
+
+    @property
+    def status_code(self):
+        """Shim to provide a similar API to other OpenStack clients."""
+        return self.status_code
+
+    @status_code.setter
+    def status_code(self, code):
+        self.status_code = code
+
+
+class ConnectionFailed(HTTPError):
+    """Connecting to the server failed."""
+
+    message = "An error occurred while connecting to the server."""
+
+
+class HTTPClientError(HTTPError):
+    """Base exception for client side errors (4xx status codes)."""
+
+    message = "Something went wrong with the request."""
+
+
+class BadRequest(HTTPClientError):
+    """Client sent a malformed request."""
+
+    status_code = 400
+    message = "The request sent to the server was invalid."
+
+
+class Unauthorized(HTTPClientError):
+    """Client is unauthorized to access the resource in question."""
+    
+    status_code = 401
+    message = ("The user has either provided insufficient parameters for "
+               "authentication or is not authorized to access this resource.")
+
+
+class Forbidden(HTTPClientError):
+    """Client is forbidden to access the resource."""
+
+    status_code = 403
+    message = ("The user was unable to access the resource because they are "
+               "forbidden.")
+
+
+class NotFound(HTTPClientError):
+    """Resource could not be found."""
+
+    status_code = 404
+    message = "The requested resource was not found."""
+
+
+class MethodNotAllowed(HTTPClientError):
+    """The request method is not supported."""
+
+    status_code = 405
+    message = "The method used in the request is not supported."
+
+
+class NotAcceptable(HTTPClientError):
+    """The requested resource can not respond with acceptable content.
+
+    Based on the Accept headers specified by the client, the resource can not
+    generate content that is an acceptable content-type.
+    """
+
+    status_code = 406
+    message = "The resource can not return acceptable content."
+
+
+class ProxyAuthenticationRequired(HTTPClientError):
+    """The client must first authenticate itself with the proxy."""
+
+    status_code = 407
+    message = "The client must first authenticate itself with a proxy."
+
+
+class Conflict(HTTPClientError):
+    """The request presents a conflict."""
+
+    status_code = 409
+    message = "The request could not be processed due to a conflict."
+
+
+class Gone(HTTPClientError):
+    """The requested resource is no longer available.
+
+    The resource requested is no longer available and will not be available
+    again.
+    """
+
+    status_code = 410
+    message = ("The resource requested is no longer available and will not be"
+               " available again.")
+
+
+class LengthRequired(HTTPClientError):
+    """The request did not specify a Content-Length header."""
+
+    status_code = 411
+    message = ("The request did not contain a Content-Length header but one"
+               " was required by the resource.")
+
+
+class PreconditionFailed(HTTPClientError):
+    """The server failed to meet one of the preconditions in the request."""
+
+    status_code = 412
+    message = ("The server failed to meet one of the preconditions in the "
+               "request.")
+
+
+class RequestEntityTooLarge(HTTPClientError):
+    """The request is larger than the server is willing or able to process."""
+
+    status_code = 413
+    message = ("The request is larger than the server is willing or able to "
+               "process.")
+
+
+class RequestUriTooLong(HTTPClientError):
+    """The URI provided was too long for the server to process."""
+
+    status_code = 414
+    message = "The URI provided was too long for the server to process."
+
+
+class UnsupportedMediaType(HTTPClientError):
+    """The request entity has a media type which is unsupported."""
+
+    status_code = 415
+    message = ("The request entity has a media type which is unsupported by "
+               "the server or resource.")
+
+
+class RequestedRangeNotSatisfiable(HTTPClientError):
+    """The requestor wanted a range but the server was unable to provide it."""
+
+    status_code = 416
+    message = ("The requestor wanted a range but the server was unable to "
+               "provide it.")
+
+
+class UnprocessableEntity(HTTPClientError):
+    """There were semantic errors in the request."""
+
+    status_code = 422
+    message = ("The request is of a valid content-type and structure but "
+               "semantically invalid.")
+
+
+_4xx_classes = [
+    BadRequest,
+    Unauthorized,
+    Forbidden,
+    NotFound,
+    MethodNotAllowed,
+    NotAcceptable,
+    ProxyAuthenticationRequired,
+    Conflict,
+    Gone,
+    LengthRequired,
+    PreconditionFailed,
+    RequestEntityTooLarge,
+    RequestUriTooLong,
+    UnsupportedMediaType,
+    RequestedRangeNotSatisfiable,
+    UnprocessableEntity,
+]
+_4xx_codes = {cls.status_code: cls for cls in _4xx_classes}
+
+
+class HTTPServerError(HTTPError):
+    """The server encountered an error it could not recover from."""
+
+    message = "HTTP Server-side Error"
+
+
+class InternalServerError(HTTPServerError):
+    """The server encountered an error it could not recover from."""
+
+    status_code = 500
+    message = ("There was an internal server error that could not be recovered"
+               " from.")
+
+
+_5xx_classes = [
+    InternalServerError,
+    # NOTE(sigmavirus24): Allow for future expansion
+]
+_5xx_codes = {cls.status_code: cls for cls in _5xx_classes}
+
+
+def error_from(response):
+    """Find an error code that matches a response status_code."""
+    if 400 <= response.status_code < 500:
+        cls = _4xx_codes.get(response.status_code, HTTPClientError)
+    elif 500 <= response.status_code < 600:
+        cls = _5xx_codes.get(response.status_code, HTTPServerError)
+    else:
+        cls = HTTPError
+
+    return cls(response=response)

cratonclient/session.py

@@ -0,0 +1,150 @@
+# -*- coding: utf-8 -*-
+
+# 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.
+"""Craton-specific session details."""
+import logging
+
+import requests
+from requests import exceptions as requests_exc
+
+import cratonclient
+from cratonclient import exceptions as exc
+
+LOG = logging.getLogger(__name__)
+
+
+class Session(object):
+    """Management class to allow different types of sessions to be used.
+
+    If an instance of Craton is deployed with Keystone Middleware, this allows
+    for a keystoneauth session to be used so authentication will happen
+    immediately.
+    """
+
+    def __init__(self, session=None, username=None, token=None, project_id=None):
+        if session is None:
+            session = requests.Session()
+
+        self._session = session
+        self._session.headers['X-Auth-User'] = username
+        self._session.headers['X-Auth-Project'] = str(project_id)
+        self._session.headers['X-Auth-Token'] = token
+
+        craton_version = 'python-cratonclient/{0} '.format(
+            cratonclient.__version__)
+        old_user_agent = self._session.headers['User-Agent']
+
+        self._session.headers['User-Agent'] = craton_version + old_user_agent
+        self._session.headers['Accept'] = 'application/json'
+
+    def delete(self, url, **kwargs):
+        return self.request('DELETE', url, **kwargs)
+
+    def get(self, url, **kwargs):
+        return self.request('GET', url, **kwargs)
+
+    def head(self, url, **kwargs):
+        return self.request('HEAD', url, **kwargs)
+
+    def options(self, url, **kwargs):
+        return self.request('OPTIONS', url, **kwargs)
+
+    def post(self, url, **kwargs):
+        return self.request('POST', url, **kwargs)
+
+    def put(self, url, **kwargs):
+        return self.request('PUT', url, **kwargs)
+
+    def request(self, method, url, **kwargs):
+        self._http_log_request(method=method,
+                          url=url,
+                          data=kwargs.get('data'),
+                          headers=kwargs.get('headers', {}).copy())
+        try:
+            response = self._session.request(method=method,
+                                             url=url,
+                                             **kwargs)
+        except requests_exc.HTTPError as err:
+            raise exc.HTTPError(exception=err, response=err.response)
+        # NOTE(sigmavirus24): The ordering of Timeout before ConnectionError
+        # is important on requests 2.x. The ConnectTimeout exception inherits
+        # from both ConnectionError and Timeout. To catch both connect and
+        # read timeouts similarly, we need to catch this one first.
+        except requests_exc.Timeout as err:
+            raise exc.Timeout(exception=err)
+        except requests_exc.ConnectionError:
+            raise exc.ConnectionFailed(exception=err)
+
+        self._http_log_response(response)
+        if response.status_code >= 400:
+            raise exc.error_from(response)
+
+        return response
+
+
+    def _http_log_request(self, url, method=None, data=None,
+                          headers=None, logger=LOG):
+        if not logger.isEnabledFor(logging.DEBUG):
+            # NOTE(morganfainberg): This whole debug section is expensive,
+            # there is no need to do the work if we're not going to emit a
+            # debug log.
+            return
+
+        string_parts = ['REQ: curl -g -i']
+
+        # NOTE(jamielennox): None means let requests do its default validation
+        # so we need to actually check that this is False.
+        if self.verify is False:
+            string_parts.append('--insecure')
+        elif isinstance(self.verify, six.string_types):
+            string_parts.append('--cacert "%s"' % self.verify)
+
+        if method:
+            string_parts.extend(['-X', method])
+
+        string_parts.append(url)
+
+        if headers:
+            for header in six.iteritems(headers):
+                string_parts.append('-H "%s: %s"'
+                                    % self._process_header(header))
+
+        if data:
+            string_parts.append("-d '%s'" % data)
+        try:
+            logger.debug(' '.join(string_parts))
+        except UnicodeDecodeError:
+            logger.debug("Replaced characters that could not be decoded"
+                         " in log output, original caused UnicodeDecodeError")
+            string_parts = [
+                encodeutils.safe_decode(
+                    part, errors='replace') for part in string_parts]
+            logger.debug(' '.join(string_parts))
+
+    def _http_log_response(self, response, logger=LOG):
+        if not logger.isEnabledFor(logging.DEBUG):
+            return
+
+        text = _remove_service_catalog(response.text)
+
+        string_parts = [
+            'RESP:',
+            '[%s]' % response.status_code
+        ]
+        for header in six.iteritems(response.headers):
+            string_parts.append('%s: %s' % self._process_header(header))
+        if text:
+            string_parts.append('\nRESP BODY: %s\n' %
+                                strutils.mask_password(text))
+
+        logger.debug(' '.join(string_parts))

cratonclient/tests/test_session.py

@@ -0,0 +1,63 @@
+# -*- coding: utf-8 -*-
+
+# 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.
+
+"""Tests for `cratonclient.session` module."""
+import uuid
+
+import requests
+
+import cratonclient
+from cratonclient import session
+from cratonclient.tests import base
+
+
+USERNAME = 'example'
+TOKEN =  uuid.uuid4().hex
+PROJECT_ID = 1
+
+class TestSession(base.TestCase):
+    """Test our session class."""
+
+    def test_uses_provided_session(self):
+        """Verify that cratonclient does not override the session parameter."""
+        requests_session = requests.Session()
+        craton = session.Session(session=requests_session)
+        self.assertIs(requests_session, craton._session)
+
+    def test_creates_new_session(self):
+        """Verify that cratonclient creates a new session."""
+        craton = session.Session()
+        self.assertIsInstance(craton._session, requests.Session)
+
+    def test_sets_authentication_parameters_as_headers(self):
+        """Verify we set auth parameters as headers on the session."""
+        requests_session = requests.Session()
+        craton = session.Session(
+            username=USERNAME,
+            token=TOKEN,
+            project_id=PROJECT_ID,
+        )
+        expected_headers = {
+            'X-Auth-User': USERNAME,
+            'X-Auth-Token': TOKEN,
+            'X-Auth-Project': str(PROJECT_ID),
+            'User-Agent': 'python-cratonclient/{0} {1}'.format(
+                cratonclient.__version__, 
+                requests_session.headers['User-Agent']),
+            'Connection': 'keep-alive',
+            'Accept-Encoding': 'gzip, deflate',
+            'Accept': 'application/json',
+        }
+        self.assertItemsEqual(expected_headers, craton._session.headers)
+

cratonclient/v1/client.py

@@ -0,0 +1,10 @@
+"""Top-level client for version 1 of Craton's API."""
+from cratonclient.v1 import regions
+
+
+class Client(object):
+    def __init__(self, session, url):
+        self._url = url
+        self._session = session
+
+        self.regions = regions.RegionManager(self._session, self._url)

cratonclient/v1/regions.py

@@ -0,0 +1,15 @@
+"""Regions manager code."""
+from cratonclient import crud
+
+
+class Region(crud.Resource):
+    """Representation of a Region."""
+    pass
+
+
+class RegionManager(crud.CRUDClient):
+    """A manager for regions."""
+
+    key = 'region'
+    base_path = '/regions'
+    resource_class = Region

requirements.txt

@@ -3,3 +3,4 @@
 # process, which may cause wedges in the gate later.
 
 pbr>=1.6
+requests>=2.10.0 # Apache-2.0

test-requirements.txt

@@ -2,7 +2,8 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-hacking<0.11,>=0.10.0
+hacking<0.12,>=0.10.0
+flake8_docstrings==0.2.1.post1 # MIT
 
 coverage>=3.6
 python-subunit>=0.0.18