Add guest disk usage via virsh guestinfo --filesystem

Query each running VM's filesystem stats through the guest agent.
Show root filesystem used/total GB with color-coded bar in VM table.
Cached at 30s TTL since disk usage changes slowly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -40,6 +40,11 @@ VM_LIVE_TTL = 5
 _prev_domstats = {"by_name": {}, "ts": 0}
 _prev_domstats_lock = threading.Lock()
 
+# VM disk stats cache (guestinfo — per-VM calls, 30s TTL)
+_vm_disk_cache = {"data": {}, "ts": 0}
+_vm_disk_lock = threading.Lock()
+VM_DISK_TTL = 30
+
 
 def parse_proc_stat():
     cores = []
@@ -236,6 +241,55 @@ def get_vm_live_stats():
     return live
 
 
+def get_vm_disk_stats(running_names):
+    """Get filesystem usage for running VMs via virsh guestinfo. Cached for VM_DISK_TTL seconds."""
+    with _vm_disk_lock:
+        now = time.time()
+        if now - _vm_disk_cache["ts"] < VM_DISK_TTL:
+            return _vm_disk_cache["data"]
+
+    disks = {}
+    for name in running_names:
+        try:
+            result = subprocess.run(
+                ["sudo", "virsh", "guestinfo", name, "--filesystem"],
+                capture_output=True, text=True, timeout=5
+            )
+            if result.returncode != 0:
+                continue
+            # Parse filesystem entries, find root mountpoint
+            fs = {}
+            for line in result.stdout.split("\n"):
+                if ":" not in line:
+                    continue
+                key, val = line.split(":", 1)
+                key = key.strip()
+                val = val.strip()
+                fs[key] = val
+            # Collect all filesystems
+            count = int(fs.get("fs.count", 0))
+            vm_disks = []
+            for i in range(count):
+                mp = fs.get(f"fs.{i}.mountpoint", "")
+                total_b = int(fs.get(f"fs.{i}.total-bytes", 0))
+                used_b = int(fs.get(f"fs.{i}.used-bytes", 0))
+                if total_b > 0:
+                    vm_disks.append({
+                        "mountpoint": mp,
+                        "total_gb": round(total_b / (1024**3), 1),
+                        "used_gb": round(used_b / (1024**3), 1),
+                    })
+            if vm_disks:
+                disks[name] = vm_disks
+        except Exception:
+            continue
+
+    with _vm_disk_lock:
+        _vm_disk_cache["data"] = disks
+        _vm_disk_cache["ts"] = time.time()
+    return disks
+
+
 def get_vm_base_info():
     """Get base VM info (dominfo). Cached for VM_BASE_TTL seconds."""
     with _vm_base_lock:
@@ -286,9 +340,11 @@ def get_vm_base_info():
 
 
 def get_vms():
-    """Get VM list with live CPU % and memory usage merged in."""
+    """Get VM list with live CPU %, memory usage, and disk usage merged in."""
     base = get_vm_base_info()
     live = get_vm_live_stats()
+    running_names = [vm["name"] for vm in base if vm["state"] == "running"]
+    disks = get_vm_disk_stats(running_names)
 
     result = []
     for vm in base:
@@ -306,6 +362,7 @@ def get_vms():
             vm["cpu_percent"] = 0.0
             vm["memory_used_mb"] = 0
             vm["memory_total_mb"] = vm["memory_mb"] if vm["state"] == "running" else 0
+        vm["disks"] = disks.get(vm["name"], [])
         result.append(vm)
     return result