From 974842696a19df0c611da41a61d976ffab702691 Mon Sep 17 00:00:00 2001
From: Sven Rebhan <srebhan@influxdata.com>
Date: Tue, 31 Oct 2023 15:43:04 +0100
Subject: [PATCH] Mark unavailable values as NaN

---
 host/host.go       | 16 +++++++++++++++-
 host/host_linux.go |  7 ++++---
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/host/host.go b/host/host.go
index a312eda9b..319e52197 100644
--- a/host/host.go
+++ b/host/host.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"math"
 	"os"
 	"runtime"
 	"time"
@@ -60,7 +61,20 @@ func (u UserStat) String() string {
 }
 
 func (t TemperatureStat) String() string {
-	s, _ := json.Marshal(t)
+	x := t
+	if math.IsNaN(x.Low) {
+		x.Low = 0
+	}
+	if math.IsNaN(x.High) {
+		x.High = 0
+	}
+	if math.IsNaN(x.Critical) {
+		x.Critical = 0
+	}
+	if math.IsNaN(x.Alarm) {
+		x.Alarm = 0
+	}
+	s, _ := json.Marshal(x)
 	return string(s)
 }
 
diff --git a/host/host_linux.go b/host/host_linux.go
index ef736db22..262c3d579 100644
--- a/host/host_linux.go
+++ b/host/host_linux.go
@@ -9,6 +9,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io"
+	"math"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -512,15 +513,15 @@ func optionalValueReadFromFile(filename string) float64 {
 
 	// Check if file exists
 	if _, err := os.Stat(filename); os.IsNotExist(err) {
-		return 0
+		return math.NaN()
 	}
 
 	if raw, err = os.ReadFile(filename); err != nil {
-		return 0
+		return math.NaN()
 	}
 
 	if value, err = strconv.ParseFloat(strings.TrimSpace(string(raw)), 64); err != nil {
-		return 0
+		return math.NaN()
 	}
 
 	return value