Add validation on virtual_cluster to forbid empty string values

internal/schema/validation/non_empty_string.go

@@ -0,0 +1,49 @@
+package validation
+
+import (
+	"context"
+	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
+
+	"github.com/hashicorp/terraform-plugin-framework-validators/helpers/validatordiag"
+)
+
+var _ validator.String = nonEmpty{}
+
+// stringNonEmpty validates that a string Attribute's length is at least a certain value.
+type nonEmpty struct {
+}
+
+// Description describes the validation in plain text formatting.
+func (validator nonEmpty) Description(_ context.Context) string {
+	return "string should not be empty"
+}
+
+// MarkdownDescription describes the validation in Markdown formatting.
+func (validator nonEmpty) MarkdownDescription(ctx context.Context) string {
+	return validator.Description(ctx)
+}
+
+// Validate performs the validation.
+func (v nonEmpty) ValidateString(ctx context.Context, request validator.StringRequest, response *validator.StringResponse) {
+	if request.ConfigValue.IsNull() || request.ConfigValue.IsUnknown() {
+		return
+	}
+
+	value := request.ConfigValue.ValueString()
+
+	if len(value) == 0 {
+		response.Diagnostics.Append(validatordiag.InvalidAttributeValueDiagnostic(
+			request.Path,
+			v.Description(ctx),
+			"\"\"",
+		))
+		return
+	}
+}
+
+// NonEmptyString returns a validator which ensures that any configured
+// attribute value a not empty string. Null (unconfigured) and unknown (known after apply)
+// values are skipped.
+func NonEmptyString() validator.String {
+	return nonEmpty{}
+}

provider_code_spec.json

@@ -989,7 +989,19 @@
                               ],
                               "schema_definition": "stringdefault.StaticString(\"passthrough\")"
                             }
-                          }
+                          },
+                          "validators": [
+                            {
+                              "custom": {
+                                "imports": [
+                                  {
+                                    "path": "github.com/conduktor/terraform-provider-conduktor/internal/schema/validation"
+                                  }
+                                ],
+                                "schema_definition": "validation.NonEmptyString()"
+                              }
+                            }
+                          ]
                         }
                       },
                       {