Adds support for Glance Tasks calls

Add tasks operations on client side to support task create,
list all and show.

DocImpact
Implement blueprint async-glance-workers

Change-Id: Ib4b8e347a8a47817e3b427c8ba024e8c32f65155

glanceclient/v2/tasks.py

@@ -0,0 +1,120 @@
+# Copyright 2013 OpenStack LLC.
+# Copyright 2013 IBM Corp.
+# 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.
+
+import six
+
+import warlock
+
+from glanceclient.common import utils
+from glanceclient.openstack.common import strutils
+from glanceclient.v2 import schemas
+
+DEFAULT_PAGE_SIZE = 20
+
+SORT_DIR_VALUES = ('asc', 'desc')
+SORT_KEY_VALUES = ('id', 'type', 'status')
+
+
+class Controller(object):
+    def __init__(self, http_client, schema_client):
+        self.http_client = http_client
+        self.schema_client = schema_client
+
+    @utils.memoized_property
+    def model(self):
+        schema = self.schema_client.get('task')
+        return warlock.model_factory(schema.raw(), schemas.SchemaBasedModel)
+
+    def list(self, **kwargs):
+        """Retrieve a listing of Task objects
+
+        :param page_size: Number of tasks to request in each paginated request
+        :returns generator over list of Tasks
+        """
+        def paginate(url):
+            resp, body = self.http_client.get(url)
+            for task in body['tasks']:
+                yield task
+            try:
+                next_url = body['next']
+            except KeyError:
+                return
+            else:
+                for task in paginate(next_url):
+                    yield task
+
+        filters = kwargs.get('filters', {})
+
+        if not kwargs.get('page_size'):
+            filters['limit'] = DEFAULT_PAGE_SIZE
+        else:
+            filters['limit'] = kwargs['page_size']
+
+        if 'marker' in kwargs:
+            filters['marker'] = kwargs['marker']
+
+        sort_key = kwargs.get('sort_key')
+        if sort_key is not None:
+            if sort_key in SORT_KEY_VALUES:
+                filters['sort_key'] = sort_key
+            else:
+                raise ValueError('sort_key must be one of the following: %s.'
+                                 % ', '.join(SORT_KEY_VALUES))
+
+        sort_dir = kwargs.get('sort_dir')
+        if sort_dir is not None:
+            if sort_dir in SORT_DIR_VALUES:
+                filters['sort_dir'] = sort_dir
+            else:
+                raise ValueError('sort_dir must be one of the following: %s.'
+                                 % ', '.join(SORT_DIR_VALUES))
+
+        for param, value in filters.items():
+            if isinstance(value, six.string_types):
+                filters[param] = strutils.safe_encode(value)
+
+        url = '/v2/tasks?%s' % six.moves.urllib.parse.urlencode(filters)
+        for task in paginate(url):
+            #NOTE(flwang): remove 'self' for now until we have an elegant
+            # way to pass it into the model constructor without conflict
+            task.pop('self', None)
+            yield self.model(**task)
+
+    def get(self, task_id):
+        """Get a task based on given task id."""
+        url = '/v2/tasks/%s' % task_id
+        resp, body = self.http_client.get(url)
+        #NOTE(flwang): remove 'self' for now until we have an elegant
+        # way to pass it into the model constructor without conflict
+        body.pop('self', None)
+        return self.model(**body)
+
+    def create(self, **kwargs):
+        """Create a new task."""
+        url = '/v2/tasks'
+        task = self.model()
+
+        for (key, value) in kwargs.items():
+            try:
+                setattr(task, key, value)
+            except warlock.InvalidOperation as e:
+                raise TypeError(unicode(e))
+
+        resp, body = self.http_client.post(url, data=task)
+        #NOTE(flwang): remove 'self' for now until we have an elegant
+        # way to pass it into the model constructor without conflict
+        body.pop('self', None)
+        return self.model(**body)