Support for markers for pagination as defined in the 1.1 spec.

4 files changed, 73 insertions, 2 deletions

diff --git a/nova/api/openstack/common.py b/nova/api/openstack/common.py
index bff050347..8cad1273a 100644
--- a/nova/api/openstack/common.py
+++ b/nova/api/openstack/common.py
@@ -20,9 +20,12 @@ from urlparse import urlparse
 import webob
 
 from nova import exception
+from nova import flags
 
+FLAGS = flags.FLAGS
 
-def limited(items, request, max_limit=1000):
+
+def limited(items, request, max_limit=FLAGS.osapi_max_limit):
     """
     Return a slice of items according to requested offset and limit.
 
@@ -56,6 +59,36 @@ def limited(items, request, max_limit=1000):
     return items[offset:range_end]
 
 
+def limited_by_marker(items, request, max_limit=FLAGS.osapi_max_limit):
+    """Return a slice of items according to the requested marker and limit."""
+
+    try:
+        marker = int(request.GET.get('marker', 0))
+    except ValueError:
+        raise webob.exc.HTTPBadRequest(_('marker param must be an integer'))
+
+    try:
+        limit = int(request.GET.get('limit', max_limit))
+    except ValueError:
+        raise webob.exc.HTTPBadRequest(_('limit param must be an integer'))
+
+    if limit < 0:
+        raise webob.exc.HTTPBadRequest(_('limit param must be positive'))
+
+    limit = min(max_limit, limit)
+    start_index = 0
+    if marker:
+        start_index = -1
+        for i, item in enumerate(items):
+            if item['id'] == marker:
+                start_index = i + 1
+                break
+        if start_index < 0:
+            raise webob.exc.HTTPBadRequest(_('marker [%s] not found' % marker))
+    range_end = start_index + limit
+    return items[start_index:range_end]
+
+
 def get_image_id_from_image_hash(image_service, context, image_hash):
     """Given an Image ID Hash, return an objectstore Image ID.
 
diff --git a/nova/api/openstack/servers.py b/nova/api/openstack/servers.py
index 0dad46268..144d14536 100644
--- a/nova/api/openstack/servers.py
+++ b/nova/api/openstack/servers.py
@@ -82,7 +82,7 @@ class Controller(wsgi.Controller):
         builder - the response model builder
         """
         instance_list = self.compute_api.get_all(req.environ['nova.context'])
-        limited_list = common.limited(instance_list, req)
+        limited_list = self._limit_items(instance_list, req)
         builder = self._get_view_builder(req)
         servers = [builder.build(inst, is_detail)['server']
                 for inst in limited_list]
@@ -551,6 +551,9 @@ class ControllerV10(Controller):
     def _get_addresses_view_builder(self, req):
         return nova.api.openstack.views.addresses.ViewBuilderV10(req)
 
+    def _limit_items(self, items, req):
+        return common.limited(items, req)
+
 
 class ControllerV11(Controller):
     def _image_id_from_req_data(self, data):
@@ -574,6 +577,9 @@ class ControllerV11(Controller):
     def _get_addresses_view_builder(self, req):
         return nova.api.openstack.views.addresses.ViewBuilderV11(req)
 
+    def _limit_items(self, items, req):
+        return common.limited_by_marker(items, req)
+
 
 class ServerCreateRequestXMLDeserializer(object):
     """
diff --git a/nova/flags.py b/nova/flags.py
index 00868d9b9..f011ab383 100644
--- a/nova/flags.py
+++ b/nova/flags.py
@@ -304,6 +304,8 @@ DEFINE_string('osapi_host', '$my_ip', 'ip of api server')
 DEFINE_string('osapi_scheme', 'http', 'prefix for openstack')
 DEFINE_integer('osapi_port', 8774, 'OpenStack API port')
 DEFINE_string('osapi_path', '/v1.0/', 'suffix for openstack')
+DEFINE_integer('osapi_max_limit', 1000,
+               'max number of items returned in a collection response')
 
 DEFINE_string('default_project', 'openstack', 'default project for openstack')
 DEFINE_string('default_image', 'ami-11111',
diff --git a/nova/tests/api/openstack/test_servers.py b/nova/tests/api/openstack/test_servers.py
index 9462bd40b..c48cc5179 100644
--- a/nova/tests/api/openstack/test_servers.py
+++ b/nova/tests/api/openstack/test_servers.py
@@ -239,6 +239,36 @@ class ServersTest(test.TestCase):
         servers = json.loads(res.body)['servers']
         self.assertEqual([s['id'] for s in servers], [1, 2])
 
+    def test_get_servers_with_bad_limit(self):
+        req = webob.Request.blank('/v1.0/servers?limit=asdf&offset=1')
+        res = req.get_response(fakes.wsgi_app())
+        self.assertEqual(res.status_int, 400)
+        self.assertTrue(res.body.find('limit param') > -1)
+
+    def test_get_servers_with_bad_offset(self):
+        req = webob.Request.blank('/v1.0/servers?limit=2&offset=asdf')
+        res = req.get_response(fakes.wsgi_app())
+        self.assertEqual(res.status_int, 400)
+        self.assertTrue(res.body.find('offset param') > -1)
+
+    def test_get_servers_with_marker(self):
+        req = webob.Request.blank('/v1.1/servers?marker=2')
+        res = req.get_response(fakes.wsgi_app())
+        servers = json.loads(res.body)['servers']
+        self.assertEqual([s['id'] for s in servers], [3, 4])
+
+    def test_get_servers_with_limit_and_marker(self):
+        req = webob.Request.blank('/v1.1/servers?limit=2&marker=1')
+        res = req.get_response(fakes.wsgi_app())
+        servers = json.loads(res.body)['servers']
+        self.assertEqual([s['id'] for s in servers], [2, 3])
+
+    def test_get_servers_with_bad_marker(self):
+        req = webob.Request.blank('/v1.1/servers?limit=2&marker=asdf')
+        res = req.get_response(fakes.wsgi_app())
+        self.assertEqual(res.status_int, 400)
+        self.assertTrue(res.body.find('marker param') > -1)
+
     def _setup_for_create_instance(self):
         """Shared implementation for tests below that create instance"""
         def instance_create(context, inst):