Update logfilter.py

- Add buffer.seek(0) after truncate to reset file pointer position
- Add isinstance and len check before accessing item[16] to prevent
  IndexError
- Improves robustness when processing malformed CSV log entries

Author: jangjangji

gpMgmt/bin/gppylib/logfilter.py

@@ -278,13 +278,17 @@ def __next__(self):
         item = next(self.source)
         #we need to make a minor format change to the log level field so that
         # our single regex will match both.
-        item[16] = item[16] + ": "
+        # Check if item has enough columns before accessing index 16
+        if isinstance(item, list) and len(item) > 16:
+            item[16] = item[16] + ": "
 
         self.buffer.truncate(0)
+        self.buffer.seek(0)
         self.writer.writerow(item)
 
         return self.buffer.getvalue()
 
+
 #------------------------------- Spying --------------------------------
 
 class Count(object):