Fix negative or 0 limit parameter in pagination

Octavia replace "limit" with None when it is less 1. (for example 0, -1)
However the further code failed to compare None and int values.
This patch fixes it by validation, that limit is None.

Co-Authored-By: Roman Goncharov <gadzhet007@gmail.com>

Closes-Bug: #2060917
Change-Id: I9bb45a1aca6b7b18644752a3dccc3ebfb7c106ef

octavia/api/common/pagination.py

@@ -169,7 +169,7 @@ class PaginationHelper:
             # TODO(rm_work) Do we need to know when there are more vs exact?
             # We safely know if we have a full page, but it might include the
             # last element or it might not, it is unclear
-            if len(model_list) >= self.limit:
+            if self.limit is None or len(model_list) >= self.limit:
                 next_attr.append("marker={}".format(model_list[-1].get('id')))
                 next_link = {
                     "rel": "next",

octavia/tests/unit/api/common/test_pagination.py

@@ -228,8 +228,9 @@ class TestPaginationHelper(base.TestCase):
         links = helper._make_links(model_list)
         self.assertEqual(links[0].rel, "previous")
         self.assertEqual(
-            links[1].href,
+            links[0].href,
-            "{base_uri}{path}?limit={limit}&marker={marker}".format(
+            ("{base_uri}{path}?limit={limit}&marker={marker}"
+             "&page_reverse=True").format(
                 base_uri=api_base_uri,
                 path=request_mock.path,
                 limit=params['limit'],
@@ -243,3 +244,69 @@ class TestPaginationHelper(base.TestCase):
                 path=request_mock.path,
                 limit=params['limit'],
                 marker=member1.id))
+
+    @mock.patch('octavia.api.common.pagination.request')
+    def test_make_links_with_zero_limit(self, request_mock):
+        request_mock.path = "/lbaas/v2/pools/1/members"
+        request_mock.path_url = "http://localhost" + request_mock.path
+        api_base_uri = "https://127.0.0.1"
+        conf = self.useFixture(oslo_fixture.Config(cfg.CONF))
+        conf.config(group='api_settings', api_base_uri=api_base_uri)
+        member1 = models.Member()
+        member1.id = uuidutils.generate_uuid()
+        model_list = [member1]
+
+        params = {'limit': 0, 'marker': member1.id}
+        helper = pagination.PaginationHelper(params)
+        links = helper._make_links(model_list)
+        self.assertEqual(links[0].rel, "previous")
+        self.assertEqual(
+            links[0].href,
+            ("{base_uri}{path}?limit={limit}&marker={marker}"
+             "&page_reverse=True").format(
+                base_uri=api_base_uri,
+                path=request_mock.path,
+                limit=None,
+                marker=member1.id
+            ))
+        self.assertEqual(links[1].rel, "next")
+        self.assertEqual(
+            links[1].href,
+            "{base_uri}{path}?limit={limit}&marker={marker}".format(
+                base_uri=api_base_uri,
+                path=request_mock.path,
+                limit=None,
+                marker=member1.id))
+
+    @mock.patch('octavia.api.common.pagination.request')
+    def test_make_links_with_negative_limit(self, request_mock):
+        request_mock.path = "/lbaas/v2/pools/1/members"
+        request_mock.path_url = "http://localhost" + request_mock.path
+        api_base_uri = "https://127.0.0.1"
+        conf = self.useFixture(oslo_fixture.Config(cfg.CONF))
+        conf.config(group='api_settings', api_base_uri=api_base_uri)
+        member1 = models.Member()
+        member1.id = uuidutils.generate_uuid()
+        model_list = [member1]
+
+        params = {'limit': -1, 'marker': member1.id}
+        helper = pagination.PaginationHelper(params)
+        links = helper._make_links(model_list)
+        self.assertEqual(links[0].rel, "previous")
+        self.assertEqual(
+            links[0].href,
+            ("{base_uri}{path}?limit={limit}&marker={marker}"
+             "&page_reverse=True").format(
+                base_uri=api_base_uri,
+                path=request_mock.path,
+                limit=None,
+                marker=member1.id
+            ))
+        self.assertEqual(links[1].rel, "next")
+        self.assertEqual(
+            links[1].href,
+            "{base_uri}{path}?limit={limit}&marker={marker}".format(
+                base_uri=api_base_uri,
+                path=request_mock.path,
+                limit=None,
+                marker=member1.id))

releasenotes/notes/Fix-limit-pagination-less-or-equal-zero-93a33f1318ea34e5.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fix the issue, when "limit" parameter in request less or equal 0.
+    Now it returns resources according pagination_max_limit as expected,
+    instead of error.