Add resource definition refactor (#278)

Add resource definition refactor

SUMMARY

This refactors most of the logic around creating a list of functional
resource definitions based on input parameters for the module.

ISSUE TYPE

COMPONENT NAME

ADDITIONAL INFORMATION

Reviewed-by: Alina Buzachis <None>
Reviewed-by: Abhijeet Kasurde <None>
Reviewed-by: Mike Graves <mgraves@redhat.com>
Reviewed-by: None <None>

plugins/module_utils/k8s/resource.py

@@ -0,0 +1,129 @@
+# Copyright: (c) 2021, Red Hat | Ansible
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+import os
+from typing import cast, Dict, Iterable, List, Optional, Union
+
+from ansible.module_utils.six import string_types
+
+try:
+    import yaml
+except ImportError:
+    # Handled in module setup
+    pass
+
+
+class ResourceDefinition(dict):
+    """Representation of a resource definition.
+
+    This is a thin wrapper around a dictionary representation of a resource
+    definition, with a few properties defined for conveniently accessing the
+    commonly used fields.
+    """
+
+    @property
+    def kind(self) -> Optional[str]:
+        return self.get("kind")
+
+    @property
+    def api_version(self) -> Optional[str]:
+        return self.get("apiVersion")
+
+    @property
+    def namespace(self) -> Optional[str]:
+        metadata = self.get("metadata", {})
+        return metadata.get("namespace")
+
+    @property
+    def name(self) -> Optional[str]:
+        metadata = self.get("metadata", {})
+        return metadata.get("name")
+
+
+def create_definitions(params: Dict) -> List[ResourceDefinition]:
+    """Create a list of ResourceDefinitions from module inputs.
+
+    This will take the module's inputs and return a list of ResourceDefintion
+    objects. The resource definitions returned by this function should be as
+    complete a definition as we can create based on the input. Any *List kinds
+    will be removed and replaced by the resources contained in it.
+    """
+    if params.get("resource_definition"):
+        d = cast(Union[str, List, Dict], params.get("resource_definition"))
+        definitions = from_yaml(d)
+    elif params.get("src"):
+        d = cast(str, params.get("src"))
+        definitions = from_file(d)
+    else:
+        # We'll create an empty definition and let merge_params set values
+        # from the module parameters.
+        definitions = [{}]
+
+    resource_definitions: List[Dict] = []
+    for definition in definitions:
+        merge_params(definition, params)
+        kind = cast(Optional[str], definition.get("kind"))
+        if kind and kind.endswith("List"):
+            resource_definitions += flatten_list_kind(definition, params)
+        else:
+            resource_definitions.append(definition)
+    return list(map(ResourceDefinition, resource_definitions))
+
+
+def from_yaml(definition: Union[str, List, Dict]) -> Iterable[Dict]:
+    """Load resource definitions from a yaml definition."""
+    definitions: List[Dict] = []
+    if isinstance(definition, string_types):
+        definitions += yaml.safe_load_all(definition)
+    elif isinstance(definition, list):
+        for item in definition:
+            if isinstance(item, string_types):
+                definitions += yaml.safe_load_all(item)
+            else:
+                definitions.append(item)
+    else:
+        definition = cast(Dict, definition)
+        definitions.append(definition)
+    return filter(None, definitions)
+
+
+def from_file(filepath: str) -> Iterable[Dict]:
+    """Load resource definitions from a path to a yaml file."""
+    path = os.path.normpath(filepath)
+    with open(path, "r") as f:
+        definitions = list(yaml.safe_load_all(f))
+    return filter(None, definitions)
+
+
+def merge_params(definition: Dict, params: Dict) -> Dict:
+    """Merge module parameters with the resource definition.
+
+    Fields in the resource definition take precedence over module parameters.
+    """
+    definition.setdefault("kind", params.get("kind"))
+    definition.setdefault("apiVersion", params.get("api_version"))
+    metadata = definition.setdefault("metadata", {})
+    # The following should only be set if we have values for them
+    if params.get("namespace"):
+        metadata.setdefault("namespace", params.get("namespace"))
+    if params.get("name"):
+        metadata.setdefault("name", params.get("name"))
+    if params.get("generate_name"):
+        metadata.setdefault("generateName", params.get("generate_name"))
+    return definition
+
+
+def flatten_list_kind(definition: Dict, params: Dict) -> List[Dict]:
+    """Replace *List kind with the items it contains.
+
+    This will take a definition for a *List resource and return a list of
+    definitions for the items contained within the List.
+    """
+    items = []
+    kind = cast(str, definition.get("kind"))[:-4]
+    api_version = definition.get("apiVersion")
+    for item in definition.get("items", []):
+        item.setdefault("kind", kind)
+        item.setdefault("apiVersion", api_version)
+        items.append(merge_params(item, params))
+    return items