Build dynamic model and modelform generation

src/servala/core/crd.py

@@ -0,0 +1,92 @@
+from django.core.validators import MaxValueValidator, MinValueValidator, RegexValidator
+from django.db import models
+from django.forms.models import ModelForm, ModelFormMetaclass
+
+
+def generate_django_model(crd, group, version, kind):
+    """
+    Generates a virtual Django model from a Kubernetes CRD's OpenAPI v3 schema.
+    """
+    schema = crd.spec.versions[0].schema.open_apiv3_schema
+    properties = schema.properties
+    required_fields = schema.required
+    model_fields = {"__module__": "crd_models"}
+
+    defaults = {"apiVersion": f"{group}/{version}", "kind": kind}
+
+    for prop_name, prop_schema in properties.items():
+        is_required = prop_name in required_fields
+        field = get_django_field(
+            prop_schema, is_required, default=defaults.get(prop_name)
+        )
+        model_fields[prop_name] = field
+
+    meta_class = type("Meta", (), {"app_label": "crd_models"})
+    model_fields["Meta"] = meta_class
+
+    # create the model class
+    model_name = crd.spec.names.kind
+    model_class = type(model_name, (models.Model,), model_fields)
+    return model_class
+
+
+def get_django_field(prop_schema, is_required=False, default=None):
+    field_type = prop_schema.type or "string"
+    format = prop_schema.format
+
+    kwargs = {
+        "blank": not is_required,
+        "null": not is_required,
+        "help_text": prop_schema.description or "",
+        "validators": [],
+        "default": default,
+        # TODO: verbose_name?
+    }
+
+    if prop_schema.minimum:
+        kwargs["validators"].append(MinValueValidator(prop_schema.minimum))
+    if prop_schema.maximum:
+        kwargs["validators"].append(MaxValueValidator(prop_schema.maximum))
+
+    if field_type == "string":
+        if format == "date-time":
+            return models.DateTimeField(**kwargs)
+        elif format == "date":
+            return models.DateField(**kwargs)
+        else:
+            max_length = prop_schema.max_length or 255
+            if prop_schema.pattern:
+                kwargs["validators"].append(RegexValidator(regex=prop_schema.pattern))
+            return models.CharField(max_length=max_length, **kwargs)
+    elif field_type == "integer":
+        return models.IntegerField(**kwargs)
+    elif field_type == "number":
+        return models.FloatField(**kwargs)
+    elif field_type == "boolean":
+        return models.BooleanField(**kwargs)
+    elif field_type == "object":
+        kwargs["help_text"] += " (JSON object)"
+        return models.JSONField(**kwargs)
+    elif field_type == "array":
+        kwargs["help_text"] += " (JSON array)"
+        return models.JSONField(**kwargs)
+    return models.CharField(max_length=255, **kwargs)
+
+
+class CrdModelFormMixin:
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.fields["apiVersion"].disabled = True
+
+
+def generate_model_form_class(model):
+    meta_attrs = {
+        "model": model,
+        "fields": "__all__",
+    }
+    fields = {
+        "Meta": type("Meta", (object,), meta_attrs),
+        "__module__": "crd_models",
+    }
+    class_name = f"{model.__name__}ModelForm"
+    return ModelFormMetaclass(class_name, (CrdModelFormMixin, ModelForm), fields)