feat(validation): add validation of kubernetes queues (#504)

Closes reanahub/reana-job-controller#493

Author: CameronMcClymont

reana_commons/validation/kubernetes_queues.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+#
+# This file is part of REANA.
+# Copyright (C) 2025 CERN.
+#
+# REANA is free software; you can redistribute it and/or modify it
+# under the terms of the MIT License; see LICENSE file for more details.
+
+"""REANA-Commons kubernetes queues validation."""
+
+from reana_commons.errors import REANAValidationError
+
+
+def validate_kubernetes_queues(
+    reana_yaml: dict,
+    kueue_enabled: bool,
+    supported_queues: list[str],
+    default_queue: str | None,
+) -> None:
+    """Validate Kubernetes queues in REANA specification file.
+
+    :param reana_yaml: dictionary which represents REANA specification file.
+    :param kueue_enabled: whether Kueue is enabled.
+    :param supported_queues: list of supported Kubernetes queues.
+    :param default_queue: default Kubernetes queue.
+
+    :raises REANAValidationError: Given Kubernetes queue specified in REANA spec file does not validate against
+        supported Kubernetes queues.
+    """
+    workflow: dict = reana_yaml["workflow"]
+    workflow_steps: list[dict] = workflow["specification"]["steps"]
+
+    for step in workflow_steps:
+        queue = step.get("kubernetes_queue")
+        if queue:
+            if not kueue_enabled:
+                raise REANAValidationError(
+                    f'Kubernetes queue "{queue}" found in step "{step.get("name")}" but Kueue is not enabled.'
+                )
+            if queue not in supported_queues:
+                raise REANAValidationError(
+                    f'Kubernetes queue "{queue}" in step "{step.get("name")}" is not in list of supported queues: {", ".join(supported_queues)}'
+                )
+        elif kueue_enabled and not default_queue:
+            raise REANAValidationError(
+                f'Kubernetes queue expected in step "{step.get("name")}" since Kueue is enabled and no default queue is set.'
+            )