Enhance disk usage retrieval with multiple fallbacks for Windows compatibility

- Implemented a new method `_get_disk_usage_safe` in `PLCDataStreamer` to safely retrieve disk usage information using `psutil` and `shutil` with fallbacks for different scenarios.
- Updated the disk usage calculation logic to handle potential errors and log warnings when disk usage retrieval fails.
- Modified the `system_state.json` to reorder active datasets and add a new `plotjuggler_path` entry.
- Added a comprehensive test script `test_disk_space.py` to validate the disk space calculation functionality via the API.

core/plc_data_streamer.py

@@ -598,7 +598,12 @@ class PLCDataStreamer:
                 os.makedirs(records_path)
 
             # Get disk usage for the drive where records are stored
-            usage = psutil.disk_usage(os.path.abspath(records_path))
+            # Use multiple fallback methods for Windows compatibility
+            usage = self._get_disk_usage_safe(records_path)
+            if usage is None:
+                if hasattr(self, "logger"):
+                    self.logger.warning("Could not get disk usage information")
+                return None
 
             # Calculate average CSV file size (estimate based on active datasets)
             avg_file_size_per_hour = self._estimate_csv_size_per_hour()
@@ -633,6 +638,63 @@ class PLCDataStreamer:
                 self.logger.error(f"Error calculating disk space: {e}")
             return None
 
+    def _get_disk_usage_safe(self, path):
+        """Safely get disk usage with Windows compatibility fallbacks"""
+        import shutil
+        from collections import namedtuple
+
+        DiskUsage = namedtuple("DiskUsage", ["total", "used", "free", "percent"])
+
+        try:
+            # Method 1: Try psutil with absolute path
+            abs_path = os.path.abspath(path)
+            usage = psutil.disk_usage(abs_path)
+            return DiskUsage(
+                total=usage.total,
+                used=usage.used,
+                free=usage.free,
+                percent=round((usage.used / usage.total) * 100, 1),
+            )
+        except (SystemError, OSError, Exception) as e:
+            if hasattr(self, "logger"):
+                self.logger.warning(f"psutil.disk_usage failed for {path}: {e}")
+
+            try:
+                # Method 2: Try psutil with drive root
+                drive = os.path.splitdrive(os.path.abspath(path))[0]
+                if drive:
+                    drive_root = drive + os.sep  # e.g., "D:\"
+                    if hasattr(self, "logger"):
+                        self.logger.info(f"Trying psutil with drive root: {drive_root}")
+                    usage = psutil.disk_usage(drive_root)
+                    return DiskUsage(
+                        total=usage.total,
+                        used=usage.used,
+                        free=usage.free,
+                        percent=round((usage.used / usage.total) * 100, 1),
+                    )
+            except Exception as e2:
+                if hasattr(self, "logger"):
+                    self.logger.warning(
+                        f"psutil.disk_usage with drive root failed: {e2}"
+                    )
+
+                try:
+                    # Method 3: Use shutil.disk_usage (Python 3.3+)
+                    if hasattr(self, "logger"):
+                        self.logger.info("Trying shutil.disk_usage as fallback")
+                    total, used, free = shutil.disk_usage(path)
+                    return DiskUsage(
+                        total=total,
+                        used=used,
+                        free=free,
+                        percent=round((used / total) * 100, 1),
+                    )
+                except Exception as e3:
+                    if hasattr(self, "logger"):
+                        self.logger.error(f"All disk usage methods failed: {e3}")
+                    return None
+
     def _estimate_csv_size_per_hour(self) -> float:
         """Estimate CSV file size per hour based on active datasets and variables"""
         try:

system_state.json

@@ -4,10 +4,11 @@
         "should_stream": false,
         "active_datasets": [
             "Fast",
-            "Test",
-            "DAR"
+            "DAR",
+            "Test"
         ]
     },
     "auto_recovery_enabled": true,
-    "last_update": "2025-08-22T15:01:09.609437"
+    "last_update": "2025-08-22T16:03:42.919215",
+    "plotjuggler_path": "C:\\Program Files\\PlotJuggler\\plotjuggler.exe"
 }

test_disk_space.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""
+Test script to validate the disk space calculation fix
+"""
+
+import requests
+import json
+import time
+
+
+def test_disk_space_api():
+    """Test the /api/status endpoint to see if disk_space_info works"""
+
+    url = "http://localhost:5050/api/status"
+
+    try:
+        print("🔍 Testing disk space calculation...")
+
+        # Make the API request
+        response = requests.get(url, timeout=10)
+
+        if response.status_code == 200:
+            data = response.json()
+
+            # Check if disk_space_info exists and is valid
+            disk_info = data.get("disk_space_info")
+
+            if disk_info is not None:
+                print("✅ Disk space information retrieved successfully!")
+                print(f"📁 Free space: {disk_info.get('free_space', 'N/A')}")
+                print(f"📊 Total space: {disk_info.get('total_space', 'N/A')}")
+                print(f"💾 Used space: {disk_info.get('used_space', 'N/A')}")
+                print(f"📈 Percent used: {disk_info.get('percent_used', 'N/A')}%")
+                print(
+                    f"⏱️  Recording time left: {disk_info.get('recording_time_left', 'N/A')}"
+                )
+                print(
+                    f"📝 Avg file size per hour: {disk_info.get('avg_file_size_per_hour', 'N/A')}"
+                )
+
+                return True
+            else:
+                print("❌ disk_space_info is null - error occurred during calculation")
+                return False
+
+        else:
+            print(f"❌ HTTP Error: {response.status_code}")
+            print(response.text)
+            return False
+
+    except requests.exceptions.RequestException as e:
+        print(f"❌ Request failed: {e}")
+        return False
+    except Exception as e:
+        print(f"❌ Unexpected error: {e}")
+        return False
+
+
+if __name__ == "__main__":
+    print("🚀 Testing disk space calculation fix...")
+    print("=" * 50)
+
+    # Wait a bit for server to be ready
+    time.sleep(2)
+
+    success = test_disk_space_api()
+
+    print("=" * 50)
+    if success:
+        print("✅ Test PASSED - Disk space calculation is working!")
+    else:
+        print("❌ Test FAILED - Disk space calculation has issues")