Implement default values in custom forms

src/servala/core/crd/forms.py

@@ -318,6 +318,9 @@ class CustomFormMixin(FormGeneratorMixin):
                     if validators:
                         field.validators.extend(validators)
 
+                if "default_value" in field_config and field.initial is None:
+                    field.initial = field_config["default_value"]
+
                 field.controlplane_field_mapping = field_name
 
     def get_fieldsets(self):

src/servala/core/schemas/form_config_schema.json

@@ -92,6 +92,10 @@
                     "type": "string",
                     "enum": ["email", "fqdn", "url", "ipv4", "ipv6"]
                   }
+                },
+                "default_value": {
+                  "type": "string",
+                  "description": "Default value for the field when creating new instances"
                 }
               }
             }

src/tests/test_form_config.py

@@ -519,3 +519,117 @@ def test_number_field_min_max_sets_widget_attributes():
         isinstance(v, MaxValueValidator) and v.limit_value == 65535
         for v in port_validators
     )
+
+
+def test_default_value_for_all_field_types():
+
+    class TestModel(models.Model):
+        name = models.CharField(max_length=100)
+        description = models.TextField()
+        port = models.IntegerField()
+        environment = models.CharField(
+            max_length=20,
+            choices=[
+                ("dev", "Development"),
+                ("staging", "Staging"),
+                ("prod", "Production"),
+            ],
+        )
+        monitoring_enabled = models.BooleanField()
+        tags = models.JSONField()
+
+        class Meta:
+            app_label = "test"
+
+    form_config = {
+        "fieldsets": [
+            {
+                "fields": [
+                    {
+                        "type": "text",
+                        "label": "Name",
+                        "controlplane_field_mapping": "name",
+                        "default_value": "default-name",
+                    },
+                    {
+                        "type": "textarea",
+                        "label": "Description",
+                        "controlplane_field_mapping": "description",
+                        "default_value": "Default description text",
+                    },
+                    {
+                        "type": "number",
+                        "label": "Port",
+                        "controlplane_field_mapping": "port",
+                        "default_value": "8080",
+                    },
+                    {
+                        "type": "choice",
+                        "label": "Environment",
+                        "controlplane_field_mapping": "environment",
+                        "default_value": "dev",
+                    },
+                    {
+                        "type": "checkbox",
+                        "label": "Enable Monitoring",
+                        "controlplane_field_mapping": "monitoring_enabled",
+                        "default_value": "true",
+                    },
+                    {
+                        "type": "array",
+                        "label": "Tags",
+                        "controlplane_field_mapping": "tags",
+                        "default_value": "tag1,tag2,tag3",
+                    },
+                ],
+            }
+        ]
+    }
+
+    form_class = generate_custom_form_class(form_config, TestModel)
+    form = form_class()
+
+    assert form.fields["name"].initial == "default-name"
+    assert form.fields["description"].initial == "Default description text"
+    assert form.fields["port"].initial == "8080"
+    assert form.fields["environment"].initial == "dev"
+    assert form.fields["monitoring_enabled"].initial == "true"
+    assert form.fields["tags"].initial == "tag1,tag2,tag3"
+
+
+def test_default_value_not_override_existing_instance():
+
+    class TestModel(models.Model):
+        name = models.CharField(max_length=100)
+        port = models.IntegerField()
+
+        class Meta:
+            app_label = "test"
+
+    form_config = {
+        "fieldsets": [
+            {
+                "fields": [
+                    {
+                        "type": "text",
+                        "label": "Name",
+                        "controlplane_field_mapping": "name",
+                        "default_value": "default-name",
+                    },
+                    {
+                        "type": "number",
+                        "label": "Port",
+                        "controlplane_field_mapping": "port",
+                        "default_value": "8080",
+                    },
+                ],
+            }
+        ]
+    }
+
+    instance = TestModel(name="existing-name", port=3000)
+    form_class = generate_custom_form_class(form_config, TestModel)
+    form = form_class(instance=instance)
+
+    assert form.initial["name"] == "existing-name"
+    assert form.initial["port"] == 3000