From 9ab359d3cf7a993d93fb49f35dcf9225dc74c756 Mon Sep 17 00:00:00 2001
From: Henry Dollman <hank@henrygd.me>
Date: Sun, 29 Sep 2024 16:36:32 -0400
Subject: [PATCH] add SENSORS env var

---
 beszel/internal/agent/agent.go  | 9 +++++++++
 beszel/internal/agent/system.go | 9 +++++++++
 2 files changed, 18 insertions(+)

diff --git a/beszel/internal/agent/agent.go b/beszel/internal/agent/agent.go
index 3ab7a57..2fc8b46 100644
--- a/beszel/internal/agent/agent.go
+++ b/beszel/internal/agent/agent.go
@@ -30,6 +30,7 @@ type Agent struct {
 	dockerClient        *http.Client                // HTTP client to query docker api
 	apiContainerList    *[]container.ApiInfo        // List of containers from docker host
 	sensorsContext      context.Context             // Sensors context to override sys location
+	sensorsWhitelist    map[string]struct{}         // List of sensors to monitor
 }
 
 func NewAgent() *Agent {
@@ -64,6 +65,14 @@ func (a *Agent) Run(pubKey []byte, addr string) {
 		)
 	}
 
+	// Set sensors whitelist
+	if sensors, exists := os.LookupEnv("SENSORS"); exists {
+		a.sensorsWhitelist = make(map[string]struct{})
+		for _, sensor := range strings.Split(sensors, ",") {
+			a.sensorsWhitelist[sensor] = struct{}{}
+		}
+	}
+
 	a.initializeSystemInfo()
 	a.initializeDiskInfo()
 	a.initializeNetIoStats()
diff --git a/beszel/internal/agent/system.go b/beszel/internal/agent/system.go
index ec8777b..ba23c09 100644
--- a/beszel/internal/agent/system.go
+++ b/beszel/internal/agent/system.go
@@ -162,6 +162,15 @@ func (a *Agent) getSystemStats() (system.Info, system.Stats) {
 				systemStats.Temperatures[sensor.SensorKey] = twoDecimals(sensor.Temperature)
 			}
 		}
+		// remove sensors from systemStats if whitelist exists and sensor is not in whitelist
+		// (do this here instead of in initial loop so we have correct keys if int was appended)
+		if a.sensorsWhitelist != nil {
+			for key := range systemStats.Temperatures {
+				if _, nameInWhitelist := a.sensorsWhitelist[key]; !nameInWhitelist {
+					delete(systemStats.Temperatures, key)
+				}
+			}
+		}
 	}
 
 	systemInfo := system.Info{