Add time-bounded wait-for-status to func tests

Replace strategy of time.sleep(s_value) waiting for an image to
reach 'active' with a time-bounded wait-for-status loop function.
That way we can have a more generous s_value, which seems to
sometimes be needed in the gates, without having to use that much
time on every run.

I picked the initial s_value as 4x what was in the current code,
though given that some of the other gate tests run >1 hour, we could
easily make it 600 sec without lengthening the current minimum
time-to-verification of a patch.

Closes-bug: #1767142
Change-Id: Ib771079348d22212c7b6d90fa89e7fd4161422d3

glance/tests/functional/ft_utils.py

@@ -0,0 +1,56 @@
+# Copyright 2018 Verizon Wireless
+# 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 time
+
+from oslo_serialization import jsonutils
+import requests
+from six.moves import http_client as http
+
+
+def wait_for_status(request_path, request_headers, status='active',
+                    max_sec=10, delay_sec=0.2, start_delay_sec=None):
+    """
+    Performs a time-bounded wait for the entity at the request_path to
+    reach the requested status.
+
+    :param request_path: path to use to make the request
+    :param request_headers: headers to use when making the request
+    :param status: the status to wait for (default: 'active')
+    :param max_sec: the maximum number of seconds to wait (default: 10)
+    :param delay_sec: seconds to sleep before the next request is
+                      made (default: 0.2)
+    :param start_delay_sec: seconds to wait before making the first
+                            request (default: None)
+    :raises Exception: if the entity fails to reach the status within
+                       the requested time or if the server returns something
+                       other than a 200 response
+    """
+    start_time = time.time()
+    done_time = start_time + max_sec
+    if start_delay_sec:
+        time.sleep(start_delay_sec)
+    while time.time() <= done_time:
+        resp = requests.get(request_path, headers=request_headers)
+        if resp.status_code != http.OK:
+            raise Exception("Received {} response from server".format(
+                resp.status_code))
+        entity = jsonutils.loads(resp.text)
+        if entity['status'] == status:
+            return
+        time.sleep(delay_sec)
+    entity_id = request_path.rsplit('/', 1)[1]
+    msg = "Entity {0} failed to reach status '{1}' within {2} sec"
+    raise Exception(msg.format(entity_id, status, max_sec))

glance/tests/functional/v2/test_images.py

@@ -15,7 +15,6 @@
 
 import os
 import signal
-import time
 import uuid
 
 from oslo_serialization import jsonutils
@@ -27,6 +26,7 @@ from six.moves import range
 from six.moves import urllib
 
 from glance.tests import functional
+from glance.tests.functional import ft_utils as func_utils
 from glance.tests import utils as test_utils
 
 
@@ -247,7 +247,12 @@ class TestImages(functional.FunctionalTest):
         # Verify image is in active state and checksum is set
         # NOTE(abhishekk): As import is a async call we need to provide
         # some timelap to complete the call.
-        time.sleep(0.5)
+        path = self._url('/v2/images/%s' % image_id)
+        func_utils.wait_for_status(request_path=path,
+                                   request_headers=self._headers(),
+                                   status='active',
+                                   max_sec=2,
+                                   delay_sec=0.2)
         _verify_image_checksum_and_status(
             checksum='8f113e38d28a79a5a451b16048cc2b72',
             status='active')
@@ -380,7 +385,13 @@ class TestImages(functional.FunctionalTest):
         # Verify image is in active state and checksum is set
         # NOTE(abhishekk): As import is a async call we need to provide
         # some timelap to complete the call.
-        time.sleep(5)
+        path = self._url('/v2/images/%s' % image_id)
+        func_utils.wait_for_status(request_path=path,
+                                   request_headers=self._headers(),
+                                   status='active',
+                                   max_sec=20,
+                                   delay_sec=0.2,
+                                   start_delay_sec=1)
         _verify_image_checksum_and_status(
             checksum='bcd65f8922f61a9e6a20572ad7aa2bdd',
             status='active')