Add compare header version function to tempest.lib

The motivation for this commit is that some API responses like
backing up a server image return the location of the image_id
in either the response body or the response header depending
on the microversion, e.g. [0]. In the case of server backup
action, image_id is added to response body in microversion 2.45.

Add `compare_version_header_to_request` to
`api_version_utils` to accept a new kwarg called
`operation`. At run time, 'eq' is translated
to the __eq__ attribute of `APIVersionRequest`.
The other operations include le, lt, gt, ge, and ne.

This makes it possible to do for example:

    if api_version_utils.compare_version_header_to_response(
            "X-OpenStack-Nova-API-Version", "2.45", resp, "lt"):
        image1_id = resp['image_id']
    else:
        image1_id = data_utils.parse_image_id(resp['location'])

Which means that if "2.45" < "microversion in resp" then
we can grab the image_id from the response body -- else we have
to grab it from resp.response['location'].

This commit:
  - adds compare_version_header_to_response to api_version_utils
    allowing to compare the request's header microversion
    to an expected microversion
  - modifies test_server_actions to use the new function in tests that
    always assume that the image_id attribute is in the resp header
    (not true across all microversions) -- this can be done to other
    tests in follow-up patch
  - adds related unit tests for all scenarios

[0] https://developer.openstack.org/api-ref/compute/#create-server-back-up-createbackup-action

Change-Id: Ib97e65cca468a09bbeaf68fcfe0e8192674a481e

releasenotes/notes/compare-header-version-func-de5139b2161b3627.yaml

@@ -0,0 +1,15 @@
+---
+features:
+  - |
+    Add a new function called ``compare_version_header_to_response`` to
+    ``tempest.lib.common.api_version_utils``, which compares the API
+    micoversion in the response header to another microversion using the
+    comparators defined in
+    ``tempest.lib.common.api_version_request.APIVersionRequest``.
+
+    It is now possible to determine how to retrieve an attribute from a
+    response body of an API call, depending on the returned microversion.
+
+    Add a new exception type called ``InvalidParam`` to
+    ``tempest.lib.exceptions``, allowing the possibility of raising an
+    exception if an invalid parameter is passed to a library function.

tempest/api/compute/servers/test_server_actions.py

@@ -23,6 +23,7 @@ from tempest.common import utils
 from tempest.common.utils.linux import remote_client
 from tempest.common import waiters
 from tempest import config
+from tempest.lib.common import api_version_utils
 from tempest.lib.common.utils import data_utils
 from tempest.lib import decorators
 from tempest.lib import exceptions as lib_exc
@@ -369,7 +370,11 @@ class ServerActionsTestJSON(base.BaseV2ComputeTest):
                                 "been successful as it should have been "
                                 "deleted during rotation.", oldest_backup)
 
-        image1_id = data_utils.parse_image_id(resp['location'])
+        if api_version_utils.compare_version_header_to_response(
+                "OpenStack-API-Version", "compute 2.45", resp, "lt"):
+            image1_id = resp['image_id']
+        else:
+            image1_id = data_utils.parse_image_id(resp['location'])
         self.addCleanup(_clean_oldest_backup, image1_id)
         waiters.wait_for_image_status(glance_client,
                                       image1_id, 'active')
@@ -380,7 +385,11 @@ class ServerActionsTestJSON(base.BaseV2ComputeTest):
                                          backup_type='daily',
                                          rotation=2,
                                          name=backup2).response
-        image2_id = data_utils.parse_image_id(resp['location'])
+        if api_version_utils.compare_version_header_to_response(
+                "OpenStack-API-Version", "compute 2.45", resp, "lt"):
+            image2_id = resp['image_id']
+        else:
+            image2_id = data_utils.parse_image_id(resp['location'])
         self.addCleanup(glance_client.delete_image, image2_id)
         waiters.wait_for_image_status(glance_client,
                                       image2_id, 'active')
@@ -419,7 +428,11 @@ class ServerActionsTestJSON(base.BaseV2ComputeTest):
                                          backup_type='daily',
                                          rotation=2,
                                          name=backup3).response
-        image3_id = data_utils.parse_image_id(resp['location'])
+        if api_version_utils.compare_version_header_to_response(
+                "OpenStack-API-Version", "compute 2.45", resp, "lt"):
+            image3_id = resp['image_id']
+        else:
+            image3_id = data_utils.parse_image_id(resp['location'])
         self.addCleanup(glance_client.delete_image, image3_id)
         # the first back up should be deleted
         waiters.wait_for_server_status(self.client, self.server_id, 'ACTIVE')

tempest/lib/common/api_version_utils.py

@@ -12,6 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_log import log as logging
 import testtools
 
 from tempest.lib.common import api_version_request
@@ -19,6 +20,7 @@ from tempest.lib import exceptions
 
 
 LATEST_MICROVERSION = 'latest'
+LOG = logging.getLogger(__name__)
 
 
 class BaseMicroversionTest(object):
@@ -120,3 +122,60 @@ def assert_version_header_matches_request(api_microversion_header_name,
                                     api_microversion,
                                     response_header))
         raise exceptions.InvalidHTTPResponseHeader(msg)
+
+
+def compare_version_header_to_response(api_microversion_header_name,
+                                       api_microversion,
+                                       response_header,
+                                       operation='eq'):
+    """Compares API microversion in response header to ``api_microversion``.
+
+    Compare the ``api_microversion`` value in response header if microversion
+    header is present in response, otherwise return false.
+
+    To make this function work for APIs which do not return microversion
+    header in response (example compute v2.0), this function does *not* raise
+    InvalidHTTPResponseHeader.
+
+    :param api_microversion_header_name: Microversion header name. Example:
+        'Openstack-Api-Version'.
+    :param api_microversion: Microversion number. Example:
+
+        * '2.10' for the old-style header name, 'X-OpenStack-Nova-API-Version'
+        * 'Compute 2.10' for the new-style header name, 'Openstack-Api-Version'
+
+    :param response_header: Response header where microversion is
+        expected to be present.
+    :param operation: The boolean operation to use to compare the
+        ``api_microversion`` to the microversion in ``response_header``.
+        Can be 'lt', 'eq', 'gt', 'le', 'ne', 'ge'. Default is 'eq'. The
+        operation type should be based on the order of the arguments:
+        ``api_microversion`` <operation> ``response_header`` microversion.
+    :returns: True if the comparison is logically true, else False if the
+        comparison is logically false or if ``api_microversion_header_name`` is
+        missing in the ``response_header``.
+    :raises InvalidParam: If the operation is not lt, eq, gt, le, ne or ge.
+    """
+    api_microversion_header_name = api_microversion_header_name.lower()
+    if api_microversion_header_name not in response_header:
+        return False
+
+    op = getattr(api_version_request.APIVersionRequest,
+                 '__%s__' % operation, None)
+
+    if op is None:
+        msg = ("Operation %s is invalid. Valid options include: lt, eq, gt, "
+               "le, ne, ge." % operation)
+        LOG.debug(msg)
+        raise exceptions.InvalidParam(invalid_param=msg)
+
+    # Remove "volume" from "volume <microversion>", for example, so that the
+    # microversion can be converted to `APIVersionRequest`.
+    api_version = api_microversion.split(' ')[-1]
+    resp_version = response_header[api_microversion_header_name].split(' ')[-1]
+    if not op(
+        api_version_request.APIVersionRequest(api_version),
+        api_version_request.APIVersionRequest(resp_version)):
+        return False
+
+    return True

tempest/lib/exceptions.py

@@ -276,3 +276,7 @@ class DeleteErrorException(TempestException):
 
 class InvalidTestResource(TempestException):
     message = "%(name)s is not a valid %(type)s, or the name is ambiguous"
+
+
+class InvalidParam(TempestException):
+    message = ("Invalid Parameter passed: %(invalid_param)s")

tempest/tests/lib/common/test_api_version_utils.py

@@ -92,24 +92,106 @@ class TestMicroversionHeaderMatches(base.TestCase):
     def test_header_matches(self):
         microversion_header_name = 'x-openstack-xyz-api-version'
         request_microversion = '2.1'
-        test_respose = {microversion_header_name: request_microversion}
+        test_response = {microversion_header_name: request_microversion}
         api_version_utils.assert_version_header_matches_request(
-            microversion_header_name, request_microversion, test_respose)
+            microversion_header_name, request_microversion, test_response)
 
     def test_header_does_not_match(self):
         microversion_header_name = 'x-openstack-xyz-api-version'
         request_microversion = '2.1'
-        test_respose = {microversion_header_name: '2.2'}
+        test_response = {microversion_header_name: '2.2'}
         self.assertRaises(
             exceptions.InvalidHTTPResponseHeader,
             api_version_utils.assert_version_header_matches_request,
-            microversion_header_name, request_microversion, test_respose)
+            microversion_header_name, request_microversion, test_response)
 
     def test_header_not_present(self):
         microversion_header_name = 'x-openstack-xyz-api-version'
         request_microversion = '2.1'
-        test_respose = {}
+        test_response = {}
         self.assertRaises(
             exceptions.InvalidHTTPResponseHeader,
             api_version_utils.assert_version_header_matches_request,
-            microversion_header_name, request_microversion, test_respose)
+            microversion_header_name, request_microversion, test_response)
+
+    def test_compare_versions_less_than(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.2'
+        test_response = {microversion_header_name: '2.1'}
+        self.assertFalse(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "lt"))
+
+    def test_compare_versions_less_than_equal(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.2'
+        test_response = {microversion_header_name: '2.1'}
+        self.assertFalse(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "le"))
+
+    def test_compare_versions_greater_than_equal(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.1'
+        test_response = {microversion_header_name: '2.2'}
+        self.assertFalse(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "ge"))
+
+    def test_compare_versions_greater_than(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.1'
+        test_response = {microversion_header_name: '2.2'}
+        self.assertFalse(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "gt"))
+
+    def test_compare_versions_equal(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.11'
+        test_response = {microversion_header_name: '2.1'}
+        self.assertFalse(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "eq"))
+
+    def test_compare_versions_not_equal(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.1'
+        test_response = {microversion_header_name: '2.1'}
+        self.assertFalse(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "ne"))
+
+    def test_compare_versions_with_name_in_microversion(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = 'volume 3.1'
+        test_response = {microversion_header_name: 'volume 3.1'}
+        self.assertTrue(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "eq"))
+
+    def test_compare_versions_invalid_operation(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.1'
+        test_response = {microversion_header_name: '2.1'}
+        self.assertRaises(
+            exceptions.InvalidParam,
+            api_version_utils.compare_version_header_to_response,
+            microversion_header_name, request_microversion, test_response,
+            "foo")
+
+    def test_compare_versions_header_not_present(self):
+        microversion_header_name = 'x-openstack-xyz-api-version'
+        request_microversion = '2.1'
+        test_response = {}
+        self.assertFalse(
+            api_version_utils.compare_version_header_to_response(
+                microversion_header_name, request_microversion, test_response,
+                "eq"))