[placement] Idempotent PUT /resource_classes/{name}

In a microversion 1.7 change PUT /resource_classes/{name} so that
creation and existence validation of a custom resource class can
happen in a single request and prevent the previous behavior of
being able to update a single resource class to a new name, which is
not desirable.

The previous update_resource_class is still in place to support
microversion 1.2-1.6.

The original resource-classs.yaml sets the default microversion
header to 'latest' so for those existing tests that are using the
old style of PUT, a '1.6' header has been added. New files for
version 1.6 (to add a "no 1.7 behavior here" test) and 1.7 (testing
the new PUT behavior and explicitly verifying POST to create is
still around) are added.

Change-Id: I95f62ab2cb1ab76d18fb52b93f87ed28e4e7b5f3
Implements: bp placement-put-resource-class

nova/api/openstack/placement/handlers/resource_class.py

@@ -164,7 +164,7 @@ def list_resource_classes(req):
 
 
 @wsgi_wrapper.PlacementWsgify
-@microversion.version_handler('1.2')
+@microversion.version_handler('1.2', '1.6')
 @util.require_content('application/json')
 def update_resource_class(req):
     """PUT to update a single resource class.
@@ -199,3 +199,38 @@ def update_resource_class(req):
     req.response.status = 200
     req.response.content_type = 'application/json'
     return req.response
+
+
+@wsgi_wrapper.PlacementWsgify  # noqa
+@microversion.version_handler('1.7')
+def update_resource_class(req):
+    """PUT to create or validate the existence of single resource class.
+
+    On a successful create return 201. Return 204 if the class already
+    exists. If the resource class is not a custom resource class, return
+    a 400. 409 might be a better choice, but 400 aligns with previous code.
+    """
+    name = util.wsgi_path_item(req.environ, 'name')
+    context = req.environ['placement.context']
+
+    # Use JSON validation to validation resource class name.
+    util.extract_json('{"name": "%s"}' % name, PUT_RC_SCHEMA_V1_2)
+
+    status = 204
+    try:
+        rc = objects.ResourceClass.get_by_name(context, name)
+    except exception.NotFound:
+        try:
+            rc = objects.ResourceClass(context, name=name)
+            rc.create()
+            status = 201
+        # We will not see ResourceClassCannotUpdateStandard because
+        # that was already caught when validating the {name}.
+        except exception.ResourceClassExists:
+            # Someone just now created the class, so stick with 204
+            pass
+
+    req.response.status = status
+    req.response.content_type = None
+    req.response.location = util.resource_class_url(req.environ, rc)
+    return req.response

nova/api/openstack/placement/microversion.py

@@ -43,6 +43,7 @@ VERSIONS = [
     '1.5',  # Adds DELETE /resource_providers/{uuid}/inventories
     '1.6',  # Adds /traits and /resource_providers{uuid}/traits resource
             # endpoints
+    '1.7',  # PUT /resource_classes/{name} is bodiless create or update
 ]
 
 

nova/api/openstack/placement/rest_api_version_history.rst

@@ -113,3 +113,13 @@ The following new routes are added:
 Custom traits must begin with the prefix "CUSTOM\_" and contain only
 the letters A through Z, the numbers 0 through 9 and the underscore "\_"
 character.
+
+1.7 Idempotent PUT /resource_classes/{name}
+-------------------------------------------
+
+The 1.7 version changes handling of `PUT /resource_classes/{name}` to be a
+create or verification of the resource class with `{name}`. If the resource
+class is a custom resource class and does not already exist it will be created
+and a ``201`` response code returned. If the class already exists the response
+code will be ``204``. This makes it possible to check or create a resource
+class in one request.

nova/tests/functional/api/openstack/placement/gabbits/microversion.yaml

@@ -39,13 +39,13 @@ tests:
   response_json_paths:
       $.errors[0].title: Not Acceptable
 
-- name: latest microversion is 1.6
+- name: latest microversion is 1.7
   GET: /
   request_headers:
       openstack-api-version: placement latest
   response_headers:
       vary: /OpenStack-API-Version/
-      openstack-api-version: placement 1.6
+      openstack-api-version: placement 1.7
 
 - name: other accept header bad version
   GET: /

nova/tests/functional/api/openstack/placement/gabbits/resource-classes-1-6.yaml

@@ -0,0 +1,21 @@
+# Confirm that 1.7 behavior of PUT resource classes is not in
+# microversion 1.6.
+fixtures:
+    - APIFixture
+
+defaults:
+    request_headers:
+        x-auth-token: admin
+        accept: application/json
+        content-type: application/json
+        OpenStack-API-Version: placement 1.6
+
+tests:
+
+- name: bodiless put
+  PUT: /resource_classes/CUSTOM_COW
+  status: 400
+  response_strings:
+      # We don't check much of this string because it is different
+      # between python 2 and 3.
+      - "Malformed JSON:"

nova/tests/functional/api/openstack/placement/gabbits/resource-classes-1-7.yaml

@@ -0,0 +1,49 @@
+fixtures:
+    - APIFixture
+
+defaults:
+    request_headers:
+        x-auth-token: admin
+        accept: application/json
+        content-type: application/json
+        OpenStack-API-Version: placement 1.7
+
+tests:
+
+- name: create new custom class with put
+  PUT: /resource_classes/CUSTOM_COW
+  status: 201
+  response_headers:
+      location: //resource_classes/CUSTOM_COW/
+
+- name: verify that class with put
+  PUT: /resource_classes/CUSTOM_COW
+  status: 204
+  response_headers:
+      location: //resource_classes/CUSTOM_COW/
+
+- name: fail to put non custom class
+  PUT: /resource_classes/COW
+  status: 400
+  response_strings:
+      - "Failed validating 'pattern'"
+
+- name: try to put standard class
+  PUT: /resource_classes/VCPU
+  status: 400
+  response_strings:
+      - "Failed validating 'pattern'"
+
+- name: try to put too long class
+  PUT: /resource_classes/CUSTOM_SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS
+  status: 400
+  response_strings:
+      - "Failed validating 'maxLength'"
+
+- name: post to create still works
+  POST: /resource_classes
+  data:
+      name: CUSTOM_SHEEP
+  status: 201
+  response_headers:
+      location: //resource_classes/CUSTOM_SHEEP/

nova/tests/functional/api/openstack/placement/gabbits/resource-classes.yaml

@@ -125,6 +125,7 @@ tests:
   PUT: /resource_classes/VCPU
   request_headers:
     content-type: application/json
+    OpenStack-API-Version: placement 1.6
   data:
       name: VCPU_ALTERNATE
   status: 400
@@ -137,6 +138,7 @@ tests:
   PUT: /resource_classes/$ENVIRON['CUSTOM_RES_CLASS']
   request_headers:
     content-type: application/json
+    OpenStack-API-Version: placement 1.6
   data:
       name: VCPU
   status: 400
@@ -157,6 +159,7 @@ tests:
   PUT: /resource_classes/CUSTOM_NFV_FOO
   request_headers:
     content-type: application/json
+    OpenStack-API-Version: placement 1.6
   data:
       name: $ENVIRON['CUSTOM_RES_CLASS']
   status: 409
@@ -170,6 +173,7 @@ tests:
   PUT: /resource_classes/$ENVIRON['CUSTOM_RES_CLASS']
   request_headers:
     content-type: application/json
+    OpenStack-API-Version: placement 1.6
   data:
       name: CUSTOM_NFV_BAR
   status: 200
@@ -234,6 +238,7 @@ tests:
   PUT: /resource_classes/$ENVIRON['CUSTOM_RES_CLASS']
   request_headers:
       content-type: application/json
+      OpenStack-API-Version: placement 1.6
   data:
       name: *name_exceeds_max_length_check
   status: 400

releasenotes/notes/idempotent-put-resource-class-dc7a267c823b7995.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    The 1.7 version of the placement API changes handling of
+    `PUT /resource_classes/{name}` to be a create or verification of the
+    resource class with `{name}`. If the resource class is a custom resource
+    class and does not already exist it will be created and a ``201`` response
+    code returned. If the class already exists the response code will be
+    ``204``. This makes it possible to check or create a resource class in one
+    request.