[PATCH v2] Adding stressor validation for stress-ng

[Sana Sharma <sansshar@redhat.com>]

Previously stressor names were unvalidated.
This has been changed so that now if the user inputs an invalid
stressor name, they get an error message telling them to check
"stress-ng --help". The list of stressors is created dynamically
during "WorkloadPrepare()"

Signed-off-by: Sana Sharma <sansshar@redhat.com>
---
 rteval/modules/loads/stressng.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/rteval/modules/loads/stressng.py b/rteval/modules/loads/stressng.py
index 32e2dbd..ed93646 100644
--- a/rteval/modules/loads/stressng.py
+++ b/rteval/modules/loads/stressng.py
@@ -10,6 +10,25 @@ from rteval.Log import Log
 from rteval.systopology import SysTopology
 from rteval.cpulist_utils import CpuList
 
+
+def get_valid_stressors():
+    """Query stress-ng for list of valid stressor names."""
+    try:
+        result = subprocess.run(['stress-ng', '--stressors'],
+                                capture_output=True, text=True, check=True)
+        return result.stdout.strip().split()
+    except (subprocess.CalledProcessError, FileNotFoundError):
+        return []
+
+def validate_stressor(stressor_name):
+    """Validate a single stressor name against stress-ng's available stressors."""
+    valid = get_valid_stressors()
+    if not valid:
+        return
+    if stressor_name not in valid:
+        raise ValueError(f"Invalid stress-ng stressor: '{stressor_name}'. "
+                        f"Run 'stress-ng --stressors' to see valid options.")
+
 class Stressng(CommandLineLoad):
     " This class creates a load module that runs stress-ng "
     def __init__(self, config, logger):
@@ -51,6 +70,7 @@ class Stressng(CommandLineLoad):
 
         # stress-ng is only run if the user specifies an stressor
         self.args = ['stress-ng']
+        validate_stressor(self.cfg.stressor)
         self.args.append(f'--{str(self.cfg.stressor)}')
         if self.cfg.workers is not None:
             self.args.append(self.cfg.workers) #default is 0
-- 
2.54.0