From 9ace77e69eaf6f687ede06abdfa56718cbed2c8f Mon Sep 17 00:00:00 2001
From: Dmitry Tantsur <divius.inside@gmail.com>
Date: Tue, 26 Mar 2019 13:45:35 +0100
Subject: [PATCH] Make PATCH a first class operation and support it for
 baremetal

The existing pattern of working with ironicclient is to use JSON patch to
update resources. To simplify migration let us support it as well.
Patching is also useful for granular updating of nested structures.

Deprecate two openstackcloud calls that are meaningless wrappers on
top of patch_machine/update_machine.

Change-Id: Idffaf8947f51e5854461808d9d42c576640bec56
---
 doc/source/user/proxies/baremetal.rst         |   4 +
 openstack/baremetal/v1/_proxy.py              |  62 ++++++++-
 openstack/baremetal/v1/chassis.py             |   1 +
 openstack/baremetal/v1/node.py                |   1 +
 openstack/baremetal/v1/port.py                |   1 +
 openstack/baremetal/v1/port_group.py          |   1 +
 openstack/cloud/_baremetal.py                 |  34 ++---
 openstack/resource.py                         | 121 ++++++++++++++----
 .../baremetal/test_baremetal_chassis.py       |  10 ++
 .../baremetal/test_baremetal_node.py          |  29 +++++
 .../baremetal/test_baremetal_port.py          |  13 ++
 .../baremetal/test_baremetal_port_group.py    |  10 ++
 .../tests/unit/cloud/test_baremetal_node.py   |   5 -
 openstack/tests/unit/test_resource.py         |  54 ++++++++
 .../baremetal-patch-feebd96b1b92f3b9.yaml     |  13 ++
 15 files changed, 304 insertions(+), 55 deletions(-)
 create mode 100644 releasenotes/notes/baremetal-patch-feebd96b1b92f3b9.yaml

diff --git a/doc/source/user/proxies/baremetal.rst b/doc/source/user/proxies/baremetal.rst
index d877f400a..7c740d92c 100644
--- a/doc/source/user/proxies/baremetal.rst
+++ b/doc/source/user/proxies/baremetal.rst
@@ -18,6 +18,7 @@ Node Operations
 
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.create_node
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.update_node
+   .. automethod:: openstack.baremetal.v1._proxy.Proxy.patch_node
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.delete_node
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.get_node
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.find_node
@@ -36,6 +37,7 @@ Port Operations
 
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.create_port
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.update_port
+   .. automethod:: openstack.baremetal.v1._proxy.Proxy.patch_port
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.delete_port
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.get_port
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.find_port
@@ -47,6 +49,7 @@ Port Group Operations
 
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.create_port_group
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.update_port_group
+   .. automethod:: openstack.baremetal.v1._proxy.Proxy.patch_port_group
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.delete_port_group
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.get_port_group
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.find_port_group
@@ -65,6 +68,7 @@ Chassis Operations
 
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.create_chassis
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.update_chassis
+   .. automethod:: openstack.baremetal.v1._proxy.Proxy.patch_chassis
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.delete_chassis
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.get_chassis
    .. automethod:: openstack.baremetal.v1._proxy.Proxy.find_chassis
diff --git a/openstack/baremetal/v1/_proxy.py b/openstack/baremetal/v1/_proxy.py
index e24b2cf43..2f95cc180 100644
--- a/openstack/baremetal/v1/_proxy.py
+++ b/openstack/baremetal/v1/_proxy.py
@@ -114,6 +114,18 @@ class Proxy(proxy.Proxy):
         """
         return self._update(_chassis.Chassis, chassis, **attrs)
 
+    def patch_chassis(self, chassis, patch):
+        """Apply a JSON patch to the chassis.
+
+        :param chassis: The value can be the ID of a chassis or a
+            :class:`~openstack.baremetal.v1.chassis.Chassis` instance.
+        :param patch: JSON patch to apply.
+
+        :returns: The updated chassis.
+        :rtype: :class:`~openstack.baremetal.v1.chassis.Chassis`
+        """
+        return self._get_resource(_chassis.Chassis, chassis).patch(self, patch)
+
     def delete_chassis(self, chassis, ignore_missing=True):
         """Delete a chassis.
 
@@ -246,8 +258,8 @@ class Proxy(proxy.Proxy):
     def update_node(self, node, retry_on_conflict=True, **attrs):
         """Update a node.
 
-        :param chassis: Either the name or the ID of a node or an instance
-            of :class:`~openstack.baremetal.v1.node.Node`.
+        :param node: The value can be the name or ID of a node or a
+            :class:`~openstack.baremetal.v1.node.Node` instance.
         :param bool retry_on_conflict: Whether to retry HTTP CONFLICT error.
             Most of the time it can be retried, since it is caused by the node
             being locked. However, when setting ``instance_id``, this is
@@ -261,6 +273,23 @@ class Proxy(proxy.Proxy):
         res = self._get_resource(_node.Node, node, **attrs)
         return res.commit(self, retry_on_conflict=retry_on_conflict)
 
+    def patch_node(self, node, patch, retry_on_conflict=True):
+        """Apply a JSON patch to the node.
+
+        :param node: The value can be the name or ID of a node or a
+            :class:`~openstack.baremetal.v1.node.Node` instance.
+        :param patch: JSON patch to apply.
+        :param bool retry_on_conflict: Whether to retry HTTP CONFLICT error.
+            Most of the time it can be retried, since it is caused by the node
+            being locked. However, when setting ``instance_id``, this is
+            a normal code and should not be retried.
+
+        :returns: The updated node.
+        :rtype: :class:`~openstack.baremetal.v1.node.Node`
+        """
+        res = self._get_resource(_node.Node, node)
+        return res.patch(self, patch, retry_on_conflict=retry_on_conflict)
+
     def set_node_provision_state(self, node, target, config_drive=None,
                                  clean_steps=None, rescue_password=None,
                                  wait=False, timeout=None):
@@ -527,7 +556,7 @@ class Proxy(proxy.Proxy):
     def update_port(self, port, **attrs):
         """Update a port.
 
-        :param chassis: Either the ID of a port or an instance
+        :param port: Either the ID of a port or an instance
             of :class:`~openstack.baremetal.v1.port.Port`.
         :param dict attrs: The attributes to update on the port represented
             by the ``port`` parameter.
@@ -537,6 +566,18 @@ class Proxy(proxy.Proxy):
         """
         return self._update(_port.Port, port, **attrs)
 
+    def patch_port(self, port, patch):
+        """Apply a JSON patch to the port.
+
+        :param port: The value can be the ID of a port or a
+            :class:`~openstack.baremetal.v1.port.Port` instance.
+        :param patch: JSON patch to apply.
+
+        :returns: The updated port.
+        :rtype: :class:`~openstack.baremetal.v1.port.Port`
+        """
+        return self._get_resource(_port.Port, port).patch(self, patch)
+
     def delete_port(self, port, ignore_missing=True):
         """Delete a port.
 
@@ -638,7 +679,7 @@ class Proxy(proxy.Proxy):
     def update_port_group(self, port_group, **attrs):
         """Update a port group.
 
-        :param chassis: Either the name or the ID of a port group or
+        :param port_group: Either the name or the ID of a port group or
             an instance of
             :class:`~openstack.baremetal.v1.port_group.PortGroup`.
         :param dict attrs: The attributes to update on the port group
@@ -649,6 +690,19 @@ class Proxy(proxy.Proxy):
         """
         return self._update(_portgroup.PortGroup, port_group, **attrs)
 
+    def patch_port_group(self, port_group, patch):
+        """Apply a JSON patch to the port_group.
+
+        :param port_group: The value can be the ID of a port group or a
+            :class:`~openstack.baremetal.v1.port_group.PortGroup` instance.
+        :param patch: JSON patch to apply.
+
+        :returns: The updated port group.
+        :rtype: :class:`~openstack.baremetal.v1.port_group.PortGroup`
+        """
+        res = self._get_resource(_portgroup.PortGroup, port_group)
+        return res.patch(self, patch)
+
     def delete_port_group(self, port_group, ignore_missing=True):
         """Delete a port group.
 
diff --git a/openstack/baremetal/v1/chassis.py b/openstack/baremetal/v1/chassis.py
index 953b1fd6b..89ac5c571 100644
--- a/openstack/baremetal/v1/chassis.py
+++ b/openstack/baremetal/v1/chassis.py
@@ -28,6 +28,7 @@ class Chassis(_common.ListMixin, resource.Resource):
     allow_commit = True
     allow_delete = True
     allow_list = True
+    allow_patch = True
     commit_method = 'PATCH'
     commit_jsonpatch = True
 
diff --git a/openstack/baremetal/v1/node.py b/openstack/baremetal/v1/node.py
index 21c41d3e3..ad2d3c74e 100644
--- a/openstack/baremetal/v1/node.py
+++ b/openstack/baremetal/v1/node.py
@@ -45,6 +45,7 @@ class Node(_common.ListMixin, resource.Resource):
     allow_commit = True
     allow_delete = True
     allow_list = True
+    allow_patch = True
     commit_method = 'PATCH'
     commit_jsonpatch = True
 
diff --git a/openstack/baremetal/v1/port.py b/openstack/baremetal/v1/port.py
index f77e70249..338c29e01 100644
--- a/openstack/baremetal/v1/port.py
+++ b/openstack/baremetal/v1/port.py
@@ -25,6 +25,7 @@ class Port(_common.ListMixin, resource.Resource):
     allow_commit = True
     allow_delete = True
     allow_list = True
+    allow_patch = True
     commit_method = 'PATCH'
     commit_jsonpatch = True
 
diff --git a/openstack/baremetal/v1/port_group.py b/openstack/baremetal/v1/port_group.py
index a6419fed8..939ad78bf 100644
--- a/openstack/baremetal/v1/port_group.py
+++ b/openstack/baremetal/v1/port_group.py
@@ -25,6 +25,7 @@ class PortGroup(_common.ListMixin, resource.Resource):
     allow_commit = True
     allow_delete = True
     allow_list = True
+    allow_patch = True
     commit_method = 'PATCH'
     commit_jsonpatch = True
 
diff --git a/openstack/cloud/_baremetal.py b/openstack/cloud/_baremetal.py
index 99d1126cb..6c05b8d7d 100644
--- a/openstack/cloud/_baremetal.py
+++ b/openstack/cloud/_baremetal.py
@@ -434,17 +434,8 @@ class BaremetalCloudMixin(_normalize.Normalizer):
 
         :returns: ``munch.Munch`` representing the newly updated node.
         """
-        node = self.baremetal.get_node(name_or_id)
-        microversion = node._get_microversion_for(self._baremetal_client,
-                                                  'commit')
-        msg = ("Error updating machine via patch operation on node "
-               "{node}".format(node=name_or_id))
-        url = '/nodes/{node_id}'.format(node_id=node.id)
         return self._normalize_machine(
-            self._baremetal_client.patch(url,
-                                         json=patch,
-                                         microversion=microversion,
-                                         error_message=msg))
+            self.baremetal.patch_node(name_or_id, patch))
 
     def update_machine(self, name_or_id, **attrs):
         """Update a machine with new configuration information
@@ -687,22 +678,17 @@ class BaremetalCloudMixin(_normalize.Normalizer):
             uuid, 'deleted', wait=wait, timeout=timeout)
 
     def set_node_instance_info(self, uuid, patch):
-        msg = ("Error updating machine via patch operation on node "
-               "{node}".format(node=uuid))
-        url = '/nodes/{node_id}'.format(node_id=uuid)
-        return self._baremetal_client.patch(url,
-                                            json=patch,
-                                            error_message=msg)
+        warnings.warn("The set_node_instance_info call is deprecated, "
+                      "use patch_machine or update_machine instead",
+                      DeprecationWarning)
+        return self.patch_machine(uuid, patch)
 
     def purge_node_instance_info(self, uuid):
-        patch = []
-        patch.append({'op': 'remove', 'path': '/instance_info'})
-        msg = ("Error updating machine via patch operation on node "
-               "{node}".format(node=uuid))
-        url = '/nodes/{node_id}'.format(node_id=uuid)
-        return self._baremetal_client.patch(url,
-                                            json=patch,
-                                            error_message=msg)
+        warnings.warn("The purge_node_instance_info call is deprecated, "
+                      "use patch_machine or update_machine instead",
+                      DeprecationWarning)
+        return self.patch_machine(uuid,
+                                  dict(path='/instance_info', op='remove'))
 
     def wait_for_baremetal_node_lock(self, node, timeout=30):
         """Wait for a baremetal node to have no lock.
diff --git a/openstack/resource.py b/openstack/resource.py
index acd227301..fb88d2087 100644
--- a/openstack/resource.py
+++ b/openstack/resource.py
@@ -387,6 +387,8 @@ class Resource(dict):
     allow_list = False
     #: Allow head operation for this resource.
     allow_head = False
+    #: Allow patch operation for this resource.
+    allow_patch = False
 
     # TODO(mordred) Unused - here for transition with OSC. Remove once
     # OSC no longer checks for allow_get
@@ -455,7 +457,7 @@ class Resource(dict):
         self._computed = _ComponentManager(
             attributes=computed,
             synchronized=_synchronized)
-        if self.commit_jsonpatch:
+        if self.commit_jsonpatch or self.allow_patch:
             # We need the original body to compare against
             if _synchronized:
                 self._original_body = self._body.attributes.copy()
@@ -698,7 +700,7 @@ class Resource(dict):
     def _clean_body_attrs(self, attrs):
         """Mark the attributes as up-to-date."""
         self._body.clean(only=attrs)
-        if self.commit_jsonpatch:
+        if self.commit_jsonpatch or self.allow_patch:
             for attr in attrs:
                 if attr in self._body:
                     self._original_body[attr] = self._body[attr]
@@ -976,7 +978,7 @@ class Resource(dict):
             body = self._consume_body_attrs(body)
             self._body.attributes.update(body)
             self._body.clean()
-            if self.commit_jsonpatch:
+            if self.commit_jsonpatch or self.allow_patch:
                 # We need the original body to compare against
                 self._original_body = body.copy()
 
@@ -1037,11 +1039,11 @@ class Resource(dict):
         Subclasses can override this method if more complex logic is needed.
 
         :param session: :class`keystoneauth1.adapter.Adapter`
-        :param action: One of "fetch", "commit", "create", "delete". Unused in
-            the base implementation.
+        :param action: One of "fetch", "commit", "create", "delete", "patch".
+            Unused in the base implementation.
         :return: microversion as string or ``None``
         """
-        if action not in ('fetch', 'commit', 'create', 'delete'):
+        if action not in ('fetch', 'commit', 'create', 'delete', 'patch'):
             raise ValueError('Invalid action: %s' % action)
 
         return self._get_microversion_for_list(session)
@@ -1234,6 +1236,14 @@ class Resource(dict):
         request = self._prepare_request(prepend_key=prepend_key,
                                         base_path=base_path,
                                         **kwargs)
+        microversion = self._get_microversion_for(session, 'commit')
+
+        return self._commit(session, request, self.commit_method, microversion,
+                            has_body=has_body,
+                            retry_on_conflict=retry_on_conflict)
+
+    def _commit(self, session, request, method, microversion, has_body=True,
+                retry_on_conflict=None):
         session = self._get_session(session)
 
         kwargs = {}
@@ -1245,28 +1255,95 @@ class Resource(dict):
             # overriding it via an explicit retry_on_conflict=False.
             kwargs['retriable_status_codes'] = retriable_status_codes - {409}
 
-        microversion = self._get_microversion_for(session, 'commit')
-
-        if self.commit_method == 'PATCH':
-            response = session.patch(
-                request.url, json=request.body, headers=request.headers,
-                microversion=microversion, **kwargs)
-        elif self.commit_method == 'POST':
-            response = session.post(
-                request.url, json=request.body, headers=request.headers,
-                microversion=microversion, **kwargs)
-        elif self.commit_method == 'PUT':
-            response = session.put(
-                request.url, json=request.body, headers=request.headers,
-                microversion=microversion, **kwargs)
-        else:
+        try:
+            call = getattr(session, method.lower())
+        except AttributeError:
             raise exceptions.ResourceFailure(
-                msg="Invalid commit method: %s" % self.commit_method)
+                msg="Invalid commit method: %s" % method)
+
+        response = call(request.url, json=request.body,
+                        headers=request.headers, microversion=microversion,
+                        **kwargs)
 
         self.microversion = microversion
         self._translate_response(response, has_body=has_body)
         return self
 
+    def _convert_patch(self, patch):
+        if not isinstance(patch, list):
+            patch = [patch]
+
+        converted = []
+        for item in patch:
+            try:
+                path = item['path']
+                parts = path.lstrip('/').split('/', 1)
+                field = parts[0]
+            except (KeyError, IndexError):
+                raise ValueError("Malformed or missing path in %s" % item)
+
+            try:
+                component = getattr(self.__class__, field)
+            except AttributeError:
+                server_field = field
+            else:
+                server_field = component.name
+
+            if len(parts) > 1:
+                new_path = '/%s/%s' % (server_field, parts[1])
+            else:
+                new_path = '/%s' % server_field
+            converted.append(dict(item, path=new_path))
+
+        return converted
+
+    def patch(self, session, patch=None, prepend_key=True, has_body=True,
+              retry_on_conflict=None, base_path=None):
+        """Patch the remote resource.
+
+        Allows modifying the resource by providing a list of JSON patches to
+        apply to it. The patches can use both the original (server-side) and
+        SDK field names.
+
+        :param session: The session to use for making this request.
+        :type session: :class:`~keystoneauth1.adapter.Adapter`
+        :param patch: Additional JSON patch as a list or one patch item.
+                      If provided, it is applied on top of any changes to the
+                      current resource.
+        :param prepend_key: A boolean indicating whether the resource_key
+                            should be prepended in a resource update request.
+                            Default to True.
+        :param bool retry_on_conflict: Whether to enable retries on HTTP
+                                       CONFLICT (409). Value of ``None`` leaves
+                                       the `Adapter` defaults.
+        :param str base_path: Base part of the URI for modifying resources, if
+                              different from
+                              :data:`~openstack.resource.Resource.base_path`.
+
+        :return: This :class:`Resource` instance.
+        :raises: :exc:`~openstack.exceptions.MethodNotSupported` if
+                 :data:`Resource.allow_patch` is not set to ``True``.
+        """
+        # The id cannot be dirty for an commit
+        self._body._dirty.discard("id")
+
+        # Only try to update if we actually have anything to commit.
+        if not patch and not self.requires_commit:
+            return self
+
+        if not self.allow_patch:
+            raise exceptions.MethodNotSupported(self, "patch")
+
+        request = self._prepare_request(prepend_key=prepend_key,
+                                        base_path=base_path, patch=True)
+        microversion = self._get_microversion_for(session, 'patch')
+        if patch:
+            request.body += self._convert_patch(patch)
+
+        return self._commit(session, request, 'PATCH', microversion,
+                            has_body=has_body,
+                            retry_on_conflict=retry_on_conflict)
+
     def delete(self, session, error_message=None):
         """Delete the remote resource based on this instance.
 
diff --git a/openstack/tests/functional/baremetal/test_baremetal_chassis.py b/openstack/tests/functional/baremetal/test_baremetal_chassis.py
index 185f2d5c6..0274eca3f 100644
--- a/openstack/tests/functional/baremetal/test_baremetal_chassis.py
+++ b/openstack/tests/functional/baremetal/test_baremetal_chassis.py
@@ -37,6 +37,16 @@ class TestBareMetalChassis(base.BaseBaremetalTest):
         chassis = self.conn.baremetal.get_chassis(chassis.id)
         self.assertEqual({'answer': 42}, chassis.extra)
 
+    def test_chassis_patch(self):
+        chassis = self.create_chassis()
+
+        chassis = self.conn.baremetal.patch_chassis(
+            chassis, dict(path='/extra/answer', op='add', value=42))
+        self.assertEqual({'answer': 42}, chassis.extra)
+
+        chassis = self.conn.baremetal.get_chassis(chassis.id)
+        self.assertEqual({'answer': 42}, chassis.extra)
+
     def test_chassis_negative_non_existing(self):
         uuid = "5c9dcd04-2073-49bc-9618-99ae634d8971"
         self.assertRaises(exceptions.ResourceNotFound,
diff --git a/openstack/tests/functional/baremetal/test_baremetal_node.py b/openstack/tests/functional/baremetal/test_baremetal_node.py
index c38fbf52a..37bdbacc1 100644
--- a/openstack/tests/functional/baremetal/test_baremetal_node.py
+++ b/openstack/tests/functional/baremetal/test_baremetal_node.py
@@ -86,6 +86,35 @@ class TestBareMetalNode(base.BaseBaremetalTest):
         node = self.conn.baremetal.get_node('node-name')
         self.assertIsNone(node.instance_id)
 
+    def test_node_patch(self):
+        node = self.create_node(name='node-name', extra={'foo': 'bar'})
+        node.name = 'new-name'
+        instance_uuid = str(uuid.uuid4())
+
+        node = self.conn.baremetal.patch_node(
+            node,
+            [dict(path='/instance_id', op='replace', value=instance_uuid),
+             dict(path='/extra/answer', op='add', value=42)])
+        self.assertEqual('new-name', node.name)
+        self.assertEqual({'foo': 'bar', 'answer': 42}, node.extra)
+        self.assertEqual(instance_uuid, node.instance_id)
+
+        node = self.conn.baremetal.get_node('new-name')
+        self.assertEqual('new-name', node.name)
+        self.assertEqual({'foo': 'bar', 'answer': 42}, node.extra)
+        self.assertEqual(instance_uuid, node.instance_id)
+
+        node = self.conn.baremetal.patch_node(
+            node,
+            [dict(path='/instance_id', op='remove'),
+             dict(path='/extra/answer', op='remove')])
+        self.assertIsNone(node.instance_id)
+        self.assertNotIn('answer', node.extra)
+
+        node = self.conn.baremetal.get_node('new-name')
+        self.assertIsNone(node.instance_id)
+        self.assertNotIn('answer', node.extra)
+
     def test_node_list_update_delete(self):
         self.create_node(name='node-name', extra={'foo': 'bar'})
         node = next(n for n in
diff --git a/openstack/tests/functional/baremetal/test_baremetal_port.py b/openstack/tests/functional/baremetal/test_baremetal_port.py
index 4dafaef74..5c41c0e8e 100644
--- a/openstack/tests/functional/baremetal/test_baremetal_port.py
+++ b/openstack/tests/functional/baremetal/test_baremetal_port.py
@@ -77,6 +77,19 @@ class TestBareMetalPort(base.BaseBaremetalTest):
         self.assertEqual('66:55:44:33:22:11', port.address)
         self.assertEqual({'answer': 42}, port.extra)
 
+    def test_port_patch(self):
+        port = self.create_port(address='11:22:33:44:55:66')
+        port.address = '66:55:44:33:22:11'
+
+        port = self.conn.baremetal.patch_port(
+            port, dict(path='/extra/answer', op='add', value=42))
+        self.assertEqual('66:55:44:33:22:11', port.address)
+        self.assertEqual({'answer': 42}, port.extra)
+
+        port = self.conn.baremetal.get_port(port.id)
+        self.assertEqual('66:55:44:33:22:11', port.address)
+        self.assertEqual({'answer': 42}, port.extra)
+
     def test_port_negative_non_existing(self):
         uuid = "5c9dcd04-2073-49bc-9618-99ae634d8971"
         self.assertRaises(exceptions.ResourceNotFound,
diff --git a/openstack/tests/functional/baremetal/test_baremetal_port_group.py b/openstack/tests/functional/baremetal/test_baremetal_port_group.py
index 24b8b3d75..bd74db5bd 100644
--- a/openstack/tests/functional/baremetal/test_baremetal_port_group.py
+++ b/openstack/tests/functional/baremetal/test_baremetal_port_group.py
@@ -72,6 +72,16 @@ class TestBareMetalPortGroup(base.BaseBaremetalTest):
         port_group = self.conn.baremetal.get_port_group(port_group.id)
         self.assertEqual({'answer': 42}, port_group.extra)
 
+    def test_port_group_patch(self):
+        port_group = self.create_port_group()
+
+        port_group = self.conn.baremetal.patch_port_group(
+            port_group, dict(path='/extra/answer', op='add', value=42))
+        self.assertEqual({'answer': 42}, port_group.extra)
+
+        port_group = self.conn.baremetal.get_port_group(port_group.id)
+        self.assertEqual({'answer': 42}, port_group.extra)
+
     def test_port_group_negative_non_existing(self):
         uuid = "5c9dcd04-2073-49bc-9618-99ae634d8971"
         self.assertRaises(exceptions.ResourceNotFound,
diff --git a/openstack/tests/unit/cloud/test_baremetal_node.py b/openstack/tests/unit/cloud/test_baremetal_node.py
index 61882ea48..f5aa18519 100644
--- a/openstack/tests/unit/cloud/test_baremetal_node.py
+++ b/openstack/tests/unit/cloud/test_baremetal_node.py
@@ -206,11 +206,6 @@ class TestBaremetalNode(base.IronicTestCase):
             'path': '/instance_info'}]
         self.fake_baremetal_node['instance_info'] = {}
         self.register_uris([
-            dict(method='GET',
-                 uri=self.get_mock_url(
-                     resource='nodes',
-                     append=[self.fake_baremetal_node['uuid']]),
-                 json=self.fake_baremetal_node),
             dict(method='PATCH',
                  uri=self.get_mock_url(
                      resource='nodes',
diff --git a/openstack/tests/unit/test_resource.py b/openstack/tests/unit/test_resource.py
index 7b44a60d3..ffb84a420 100644
--- a/openstack/tests/unit/test_resource.py
+++ b/openstack/tests/unit/test_resource.py
@@ -1336,6 +1336,60 @@ class TestResourceActions(base.TestCase):
 
         self.session.put.assert_not_called()
 
+    def test_patch_with_sdk_names(self):
+        class Test(resource.Resource):
+            allow_patch = True
+
+            id = resource.Body('id')
+            attr = resource.Body('attr')
+            nested = resource.Body('renamed')
+            other = resource.Body('other')
+
+        test_patch = [{'path': '/attr', 'op': 'replace', 'value': 'new'},
+                      {'path': '/nested/dog', 'op': 'remove'},
+                      {'path': '/nested/cat', 'op': 'add', 'value': 'meow'}]
+        expected = [{'path': '/attr', 'op': 'replace', 'value': 'new'},
+                    {'path': '/renamed/dog', 'op': 'remove'},
+                    {'path': '/renamed/cat', 'op': 'add', 'value': 'meow'}]
+        sot = Test.existing(id=1, attr=42, nested={'dog': 'bark'})
+        sot.patch(self.session, test_patch)
+        self.session.patch.assert_called_once_with(
+            '/1', json=expected, headers=mock.ANY, microversion=None)
+
+    def test_patch_with_server_names(self):
+        class Test(resource.Resource):
+            allow_patch = True
+
+            id = resource.Body('id')
+            attr = resource.Body('attr')
+            nested = resource.Body('renamed')
+            other = resource.Body('other')
+
+        test_patch = [{'path': '/attr', 'op': 'replace', 'value': 'new'},
+                      {'path': '/renamed/dog', 'op': 'remove'},
+                      {'path': '/renamed/cat', 'op': 'add', 'value': 'meow'}]
+        sot = Test.existing(id=1, attr=42, nested={'dog': 'bark'})
+        sot.patch(self.session, test_patch)
+        self.session.patch.assert_called_once_with(
+            '/1', json=test_patch, headers=mock.ANY, microversion=None)
+
+    def test_patch_with_changed_fields(self):
+        class Test(resource.Resource):
+            allow_patch = True
+
+            attr = resource.Body('attr')
+            nested = resource.Body('renamed')
+            other = resource.Body('other')
+
+        sot = Test.existing(id=1, attr=42, nested={'dog': 'bark'})
+        sot.attr = 'new'
+        sot.patch(self.session, {'path': '/renamed/dog', 'op': 'remove'})
+
+        expected = [{'path': '/attr', 'op': 'replace', 'value': 'new'},
+                    {'path': '/renamed/dog', 'op': 'remove'}]
+        self.session.patch.assert_called_once_with(
+            '/1', json=expected, headers=mock.ANY, microversion=None)
+
     def test_delete(self):
         result = self.sot.delete(self.session)
 
diff --git a/releasenotes/notes/baremetal-patch-feebd96b1b92f3b9.yaml b/releasenotes/notes/baremetal-patch-feebd96b1b92f3b9.yaml
new file mode 100644
index 000000000..bcf4edb3f
--- /dev/null
+++ b/releasenotes/notes/baremetal-patch-feebd96b1b92f3b9.yaml
@@ -0,0 +1,13 @@
+---
+features:
+  - |
+    Adds support for changing bare metal resources by providing a JSON patch.
+    Adds the following calls to the bare metal proxy: ``patch_node``,
+    ``patch_port``, ``patch_port_group`` and ``patch_chassis``.
+deprecations:
+  - |
+    The ``set_node_instance_info`` call is deprecated, use ``patch_machine``
+    with the same arguments instead.
+  - |
+    The ``purge_node_instance_info`` call is deprecated, use ``patch_machine``
+    or ``update_machine`` instead.