fix(monitor): read the node name without waiting for the Proxmox API

AppImage/scripts/flask_server.py

@@ -113,16 +113,17 @@ logging.basicConfig(
 # -------------------------------------------------------------------
 _PROXMOX_NODE_CACHE = {"name": None, "timestamp": 0.0}
 _PROXMOX_NODE_CACHE_TTL = 300  # seconds (5 minutes)
+_PVE_LOCAL_NODE_LINK = "/etc/pve/local"
 
 
 def get_proxmox_node_name() -> str:
     """
-    Retrieve the real Proxmox node name for the LOCAL node.
+    The name of the LOCAL node in Proxmox.
 
-    - First tries reading from: `pvesh get /nodes`
-    - In a cluster, matches the local hostname against the node list
-    - Uses an in-memory cache to avoid repeated API calls
-    - Falls back to the short hostname if the API call fails
+    `/etc/pve/local` is a link to the folder of the local node, on a single
+    host and on every node of a cluster, so the name is read from it without
+    asking the API. The short hostname is used while `/etc/pve` is not
+    mounted; that answer is not kept, so the link is read again next time.
     """
     now = time.time()
     cached_name = _PROXMOX_NODE_CACHE.get("name")
@@ -132,52 +133,17 @@ def get_proxmox_node_name() -> str:
     if cached_name and (now - float(cached_ts)) < _PROXMOX_NODE_CACHE_TTL:
         return str(cached_name)
 
-    # Get local hostname for matching
-    local_hostname = socket.gethostname().split(".", 1)[0].lower()
-
-    # Try Proxmox API
     try:
-        result = subprocess.run(
-            ["pvesh", "get", "/nodes", "--output-format", "json"],
-            capture_output=True,
-            text=True,
-            timeout=5,
-            check=False,
-        )
-
-        if result.returncode == 0 and result.stdout:
-            nodes = json.loads(result.stdout)
-            if isinstance(nodes, list) and nodes:
-                # In a cluster, find the node that matches local hostname
-                # Node names in Proxmox typically match the hostname
-                for node_info in nodes:
-                    node_name = node_info.get("node", "")
-                    if node_name.lower() == local_hostname:
-                        _PROXMOX_NODE_CACHE["name"] = node_name
-                        _PROXMOX_NODE_CACHE["timestamp"] = now
-                        return node_name
-                
-                # If no exact match, try partial match (hostname might be truncated)
-                for node_info in nodes:
-                    node_name = node_info.get("node", "")
-                    if local_hostname.startswith(node_name.lower()) or node_name.lower().startswith(local_hostname):
-                        _PROXMOX_NODE_CACHE["name"] = node_name
-                        _PROXMOX_NODE_CACHE["timestamp"] = now
-                        return node_name
-                
-                # Last resort: if single node cluster, use that node
-                if len(nodes) == 1:
-                    node_name = nodes[0].get("node")
-                    if node_name:
-                        _PROXMOX_NODE_CACHE["name"] = node_name
-                        _PROXMOX_NODE_CACHE["timestamp"] = now
-                        return node_name
-
-    except Exception as exc:
-        logger.warning("Failed to get Proxmox node name from API: %s", exc)
+        node_name = os.path.basename(os.readlink(_PVE_LOCAL_NODE_LINK))
+    except OSError:
+        node_name = ""
+    if re.fullmatch(r"[A-Za-z0-9](?:[A-Za-z0-9-]*[A-Za-z0-9])?", node_name):
+        _PROXMOX_NODE_CACHE["name"] = node_name
+        _PROXMOX_NODE_CACHE["timestamp"] = now
+        return node_name
 
     # Fallback: short hostname (without domain)
-    return local_hostname
+    return socket.gethostname().split(".", 1)[0].lower()
 
 
 # -------------------------------------------------------------------

AppImage/scripts/tests/test_proxmox_node_name.py

@@ -0,0 +1,61 @@
+"""The name of the local node is read from the link Proxmox keeps for it, so
+finding it out never waits for the API, however slow the host."""
+import ast
+import os
+from pathlib import Path
+import re
+import socket
+import tempfile
+import time
+import unittest
+
+SERVER = Path(__file__).resolve().parents[1] / 'flask_server.py'
+
+
+class NodeNameTests(unittest.TestCase):
+    def setUp(self):
+        tree = ast.parse(SERVER.read_text(encoding='utf-8'))
+        nodes = [n for n in tree.body if isinstance(n, ast.FunctionDef) and n.name == 'get_proxmox_node_name']
+        self.assertEqual(len(nodes), 1)
+        self.source = ast.get_source_segment(SERVER.read_text(encoding='utf-8'), nodes[0])
+        folder = tempfile.TemporaryDirectory()
+        self.addCleanup(folder.cleanup)
+        self.link = os.path.join(folder.name, 'local')
+
+        def no_subprocess(*args, **kwargs):
+            raise AssertionError('the node name must not run a command')
+
+        self.scope = {'os': os, 're': re, 'socket': socket, 'time': time,
+                      'subprocess': type('S', (), {'run': staticmethod(no_subprocess)}),
+                      '_PROXMOX_NODE_CACHE': {'name': None, 'timestamp': 0.0}, '_PROXMOX_NODE_CACHE_TTL': 300,
+                      '_PVE_LOCAL_NODE_LINK': self.link}
+        exec(compile(ast.Module(body=nodes, type_ignores=[]), str(SERVER), 'exec'), self.scope)
+        self.name = self.scope['get_proxmox_node_name']
+
+    def test_the_name_is_the_folder_the_link_points_to(self):
+        os.symlink('nodes/Hades-01', self.link)
+        self.assertEqual(self.name(), 'Hades-01')
+
+    def test_the_api_is_not_asked(self):
+        self.assertNotIn('pvesh', self.source)
+        self.assertNotIn('subprocess', self.source)
+
+    def test_without_the_link_the_hostname_is_used_and_not_kept(self):
+        hostname = socket.gethostname().split('.', 1)[0].lower()
+        self.assertEqual(self.name(), hostname)
+        os.symlink('nodes/pve2', self.link)
+        self.assertEqual(self.name(), 'pve2')
+
+    def test_the_answer_is_kept_once_read(self):
+        os.symlink('nodes/pve1', self.link)
+        self.assertEqual(self.name(), 'pve1')
+        os.unlink(self.link)
+        self.assertEqual(self.name(), 'pve1')
+
+    def test_a_link_that_names_no_node_is_not_taken(self):
+        os.symlink('nodes/bad name', self.link)
+        self.assertEqual(self.name(), socket.gethostname().split('.', 1)[0].lower())
+
+
+if __name__ == '__main__':
+    unittest.main()