Add validate helper function (#199)

* Add validate method to dynamic client

Uses kubernetes-validate to validate resource definitions

* Ignore B306 for ValidationError

ValidationError provides its own e.message

* Fix validate parameter name

Rename `resource` to `definition` and remove legacy `client`
parameter from docs

(cherry picked from commit 44fdf7a)

openshift/dynamic/client.py

@@ -11,7 +11,14 @@
 from kubernetes.client.api_client import ApiClient
 from kubernetes.client.rest import ApiException
 
-from openshift.dynamic.exceptions import ResourceNotFoundError, ResourceNotUniqueError, api_exception
+from openshift.dynamic.exceptions import ResourceNotFoundError, ResourceNotUniqueError, api_exception, KubernetesValidateMissing
+
+try:
+    import kubernetes_validate
+    HAS_KUBERNETES_VALIDATE = True
+except ImportError:
+    HAS_KUBERNETES_VALIDATE = False
+
 
 __all__ = [
     'DynamicClient',
@@ -256,6 +263,37 @@ def request(self, method, path, body=None, **params):
         )
 
 
+    def validate(self, definition, version=None, strict=False):
+        """validate checks a kubernetes resource definition
+
+        Args:
+            definition (dict): resource definition
+            version (str): version of kubernetes to validate against
+            strict (bool): whether unexpected additional properties should be considered errors
+
+        Returns:
+            warnings (list), errors (list): warnings are missing validations, errors are validation failures
+        """
+        if not HAS_KUBERNETES_VALIDATE:
+            raise KubernetesValidateMissing()
+
+        errors = list()
+        warnings = list()
+        try:
+            if version is None:
+                try:
+                    version = self.version['kubernetes']['gitVersion']
+                except KeyError:
+                    version = kubernetes_validate.latest_version()
+            kubernetes_validate.validate(definition, version, strict)
+        except kubernetes_validate.utils.ValidationError as e:
+            errors.append("resource definition validation error at %s: %s" % ('.'.join([str(item) for item in e.path]), e.message))  # noqa: B306
+        except kubernetes_validate.utils.SchemaNotFoundError as e:
+            warnings.append("Could not find schema for object kind %s with API version %s in Kubernetes version %s (possibly Custom Resource?)" %
+                            (e.kind, e.api_version, e.version))
+        return warnings, errors
+
+
 class Resource(object):
     """ Represents an API resource type, containing the information required to build urls for requests """
 

openshift/dynamic/exceptions.py

@@ -54,6 +54,9 @@ class ResourceNotFoundError(Exception):
 class ResourceNotUniqueError(Exception):
     """ Parameters given matched multiple API resources """
 
+class KubernetesValidateMissing(Exception):
+    """ kubernetes-validate is not installed """
+
 # HTTP Errors
 class BadRequestError(DynamicApiError):
     """ 400: StatusBadRequest """
@@ -79,3 +82,4 @@ class ServiceUnavailableError(DynamicApiError):
     """ 503: StatusServiceUnavailable """
 class ServerTimeoutError(DynamicApiError):
     """ 504: StatusServerTimeout """
+