From f2e26efff093c8b7b34568cc88442f432e12db4b Mon Sep 17 00:00:00 2001
From: Renaud ZERT <renaud@trezit.com>
Date: Tue, 29 Sep 2026 17:13:53 +0200
Subject: [PATCH] Handle missing time_since_update in diskio data

Glances v4 only adds "time_since_update" (and the rates) to a plugin's
stats once a previous sample exists. The first diskio sample after the
Glances server starts therefore lacks it, and get_ha_sensor_data()
raised KeyError. In Home Assistant this fails the config entry setup
for good when Glances and Home Assistant start together (host reboot).

Keep the disk with read/write set to None for that sample, like the
network sensors, so the entities are still created and get values on
the next update.

Fixes #57

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 glances_api/__init__.py | 11 ++++++++---
 tests/test_responses.py | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/glances_api/__init__.py b/glances_api/__init__.py
index 5522ae9..d2a054c 100644
--- a/glances_api/__init__.py
+++ b/glances_api/__init__.py
@@ -227,9 +227,14 @@ async def get_ha_sensor_data(self) -> dict[str, Any]:
         if data := self.data.get("diskio"):
             sensor_data["diskio"] = {}
             for disk in data:
-                time_since_update = disk["time_since_update"]
+                read = write = None
+                # Glances v4 omits "time_since_update" on the first sample after
+                # the server starts, as there is no previous sample to compare to
+                if time_since_update := disk.get("time_since_update"):
+                    read = round(disk["read_bytes"] / time_since_update)
+                    write = round(disk["write_bytes"] / time_since_update)
                 sensor_data["diskio"][disk["disk_name"]] = {
-                    "read": round(disk["read_bytes"] / time_since_update),
-                    "write": round(disk["write_bytes"] / time_since_update),
+                    "read": read,
+                    "write": write,
                 }
         return sensor_data
diff --git a/tests/test_responses.py b/tests/test_responses.py
index 16fffc9..b8c7409 100644
--- a/tests/test_responses.py
+++ b/tests/test_responses.py
@@ -453,6 +453,38 @@ async def test_ha_sensor_data(
     assert result == expected
 
 
+@pytest.mark.asyncio
+async def test_ha_sensor_data_diskio_first_sample(httpx_mock: HTTPXMock) -> None:
+    """Test the diskio sensors on the first sample after Glances v4 starts."""
+    # No previous sample yet: no "time_since_update", no rates, raw counters
+    response = {
+        **RESPONSE_V4,
+        "diskio": [
+            {
+                "read_count": 442933,
+                "write_count": 937984,
+                "read_bytes": 15653558272,
+                "write_bytes": 16872076288,
+                "read_time": 64763666,
+                "write_time": 171581008,
+                "key": "disk_name",
+                "disk_name": "nvme0n1",
+            },
+        ],
+    }
+    expected = {
+        **HA_SENSOR_DATA_V4,
+        "diskio": {"nvme0n1": {"read": None, "write": None}},
+    }
+
+    httpx_mock.add_response(json=response)
+
+    client = Glances(version=4)
+    result = await client.get_ha_sensor_data()
+
+    assert result == expected
+
+
 @pytest.mark.asyncio
 async def test_ha_sensor_data_with_incomplete_container_information(
     httpx_mock: HTTPXMock,