feat: monitor connected Wi-Fi signal per interface (#2367)

internal/records/records.go

@@ -267,6 +267,9 @@ func AverageSystemStatsSlice(records []system.Stats) system.Stats {
 		return sum
 	}
 
+	// RSSI averages exclude absent and unavailable samples.
+	wifiSums := make(map[string]float64)
+	wifiCounts := make(map[string]int)
 	// necessary because uint8 is not big enough for the sum
 	batterySum := 0
 	batteryCount := 0
@@ -285,6 +288,16 @@ func AverageSystemStatsSlice(records []system.Stats) system.Stats {
 	// Accumulate totals
 	for i := range records {
 		stats := &records[i]
+		for id, reading := range stats.WiFi {
+			if sum.WiFi == nil {
+				sum.WiFi = make(map[string]system.WiFi)
+			}
+			sum.WiFi[id] = system.WiFi{SSID: reading.SSID}
+			if reading.Signal != nil {
+				wifiSums[id] += *reading.Signal
+				wifiCounts[id]++
+			}
+		}
 
 		sum.Cpu += stats.Cpu
 		// accumulate cpu time breakdowns if present
@@ -614,6 +627,14 @@ func AverageSystemStatsSlice(records []system.Stats) system.Stats {
 		sum.CpuBreakdown = avg
 	}
 
+	for id, reading := range sum.WiFi {
+		if wifiCounts[id] > 0 {
+			average := wifiSums[id] / float64(wifiCounts[id])
+			reading.Signal = &average
+			sum.WiFi[id] = reading
+		}
+	}
+
 	return sum
 }
 

internal/records/records_wifi_test.go

@@ -0,0 +1,26 @@
+package records
+
+import (
+	"testing"
+
+	"github.com/henrygd/beszel/internal/entities/system"
+)
+
+func TestWiFiAverageAvailableSamples(t *testing.T) {
+	a, b, c := -40.0, -60.0, -80.0
+	input := []system.Stats{
+		{WiFi: map[string]system.WiFi{"wlan0": {SSID: "old", Signal: &a}}},
+		{},
+		{WiFi: map[string]system.WiFi{"wlan0": {SSID: "new", Signal: &b}, "wlan1": {Signal: &c}, "unknown": {}}},
+	}
+	result := AverageSystemStatsSlice(input)
+	if len(result.WiFi) != 3 || *result.WiFi["wlan0"].Signal != -50 || *result.WiFi["wlan1"].Signal != -80 || result.WiFi["unknown"].Signal != nil || result.WiFi["wlan0"].SSID != "new" {
+		t.Fatalf("%#v", result.WiFi)
+	}
+	if *input[0].WiFi["wlan0"].Signal != -40 {
+		t.Fatal("mutated input")
+	}
+	if len(AverageSystemStatsSlice([]system.Stats{{}, {}}).WiFi) != 0 {
+		t.Fatal("invented wifi")
+	}
+}