Refactor Packages and AppCatalog pagination

Move function for getting list of Application packages to a separate
module - muranodashboard.api.packages, so both Packages and AppCatalog
views can reuse it. That `package_list()` function obtains packages
generator with a call to `muranoclient.packages.filter()` and paginate
the results, adding `has_more_data` flag (as it is done for Glance,
see http://tinyurl.com/lkbnsed).

Also move muranoclient-specific functions from
muranodashboard.environments.api to muranodashboard.api module.

Implements: blueprint app-catalog-pagination
Change-Id: Ic3a433c8467fda94ac7dd3800c29fc1c2b9f3464

muranodashboard/api/__init__.py

@@ -0,0 +1,93 @@
+#    Copyright (c) 2014 Mirantis, Inc.
+#
+#    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 contextlib
+import logging
+
+from django.conf import settings
+from django.contrib.messages import api as msg_api
+from django.utils.encoding import force_unicode
+from django.utils.translation import ugettext_lazy as _
+from horizon import exceptions
+from openstack_dashboard.api import base
+
+import muranoclient.client as client
+from muranoclient.common import exceptions as exc
+
+
+LOG = logging.getLogger(__name__)
+
+
+def _handle_message(request, message):
+    def horizon_message_already_queued(_message):
+        _message = force_unicode(_message)
+        if request.is_ajax():
+            for tag, msg, extra in request.horizon['async_messages']:
+                if _message == msg:
+                    return True
+        else:
+            for msg in msg_api.get_messages(request):
+                if msg.message == _message:
+                    return True
+        return False
+
+    if horizon_message_already_queued(message):
+        exceptions.handle(request, ignore=True)
+    else:
+        exceptions.handle(request, message=message)
+
+
+@contextlib.contextmanager
+def handled_exceptions(request):
+    """Handles all murano-api specific exceptions."""
+    try:
+        yield
+    except exc.CommunicationError:
+        msg = _('Unable to communicate to murano-api server.')
+        LOG.exception(msg)
+        _handle_message(request, msg)
+    except exc.Unauthorized:
+        msg = _('Check Keystone configuration of murano-api server.')
+        LOG.exception(msg)
+        _handle_message(request, msg)
+    except exc.Forbidden:
+        msg = _('Operation is forbidden by murano-api server.')
+        LOG.exception(msg)
+        _handle_message(request, msg)
+
+
+def _get_endpoint(request):
+    #prefer location specified in settings for dev purposes
+    endpoint = getattr(settings, 'MURANO_API_URL', None)
+
+    if not endpoint:
+        try:
+            endpoint = base.url_for(request, 'application_catalog')
+        except exceptions.ServiceCatalogException:
+            endpoint = 'http://localhost:8082'
+            LOG.warning('Murano API location could not be found in Service '
+                        'Catalog, using default: {0}'.format(endpoint))
+    return endpoint
+
+
+def muranoclient(request):
+    endpoint = _get_endpoint(request)
+    insecure = getattr(settings, 'MURANO_API_INSECURE', False)
+
+    token_id = request.user.token.id
+    LOG.debug('Murano::Client <Url: {0}, '
+              'TokenId: {1}>'.format(endpoint, token_id))
+
+    return client.Client(1, endpoint=endpoint, token=token_id,
+                         insecure=insecure)

muranodashboard/api/packages.py

@@ -0,0 +1,49 @@
+#    Copyright (c) 2014 Mirantis, Inc.
+#
+#    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 itertools
+
+from django.conf import settings
+
+from muranodashboard import api
+
+
+def package_list(request, marker=None, filters=None, paginate=False,
+                 page_size=20):
+    limit = getattr(settings, 'PACKAGES_LIMIT', 100)
+    filters = filters or {}
+
+    if paginate:
+        request_size = page_size + 1
+    else:
+        request_size = limit
+
+    if marker:
+        filters['marker'] = marker
+
+    client = api.muranoclient(request)
+    packages_iter = client.packages.filter(page_size=request_size,
+                                           limit=limit,
+                                           **filters)
+
+    has_more_data = False
+    if paginate:
+        packages = list(itertools.islice(packages_iter, request_size))
+        if len(packages) > page_size:
+            packages.pop()
+            has_more_data = True
+    else:
+        packages = list(packages_iter)
+
+    return packages, has_more_data