feat(agent): NETWORK env var and support for multiple keys

- merges agent.Run with agent.NewAgent
- separates StartServer method
- bumps go version to 1.24
- add tests

beszel/internal/agent/agent.go

@@ -28,29 +28,16 @@ type Agent struct {
 }
 
 func NewAgent() *Agent {
-	newAgent := &Agent{
-		sensorsContext: context.Background(),
-		fsStats:        make(map[string]*system.FsStats),
+	agent := &Agent{
+		fsStats: make(map[string]*system.FsStats),
 	}
-	newAgent.memCalc, _ = GetEnv("MEM_CALC")
-	return newAgent
-}
+	agent.memCalc, _ = GetEnv("MEM_CALC")
 
-// GetEnv retrieves an environment variable with a "BESZEL_AGENT_" prefix, or falls back to the unprefixed key.
-func GetEnv(key string) (value string, exists bool) {
-	if value, exists = os.LookupEnv("BESZEL_AGENT_" + key); exists {
-		return value, exists
-	}
-	// Fallback to the old unprefixed key
-	return os.LookupEnv(key)
-}
-
-func (a *Agent) Run(pubKey []byte, addr string) {
 	// Set up slog with a log level determined by the LOG_LEVEL env var
 	if logLevelStr, exists := GetEnv("LOG_LEVEL"); exists {
 		switch strings.ToLower(logLevelStr) {
 		case "debug":
-			a.debug = true
+			agent.debug = true
 			slog.SetLogLoggerLevel(slog.LevelDebug)
 		case "warn":
 			slog.SetLogLoggerLevel(slog.LevelWarn)
@@ -64,40 +51,51 @@ func (a *Agent) Run(pubKey []byte, addr string) {
 	// Set sensors context (allows overriding sys location for sensors)
 	if sysSensors, exists := GetEnv("SYS_SENSORS"); exists {
 		slog.Info("SYS_SENSORS", "path", sysSensors)
-		a.sensorsContext = context.WithValue(a.sensorsContext,
+		agent.sensorsContext = context.WithValue(agent.sensorsContext,
 			common.EnvKey, common.EnvMap{common.HostSysEnvKey: sysSensors},
 		)
+	} else {
+		agent.sensorsContext = context.Background()
 	}
 
 	// Set sensors whitelist
 	if sensors, exists := GetEnv("SENSORS"); exists {
-		a.sensorsWhitelist = make(map[string]struct{})
+		agent.sensorsWhitelist = make(map[string]struct{})
 		for _, sensor := range strings.Split(sensors, ",") {
 			if sensor != "" {
-				a.sensorsWhitelist[sensor] = struct{}{}
+				agent.sensorsWhitelist[sensor] = struct{}{}
 			}
 		}
 	}
 
 	// initialize system info / docker manager
-	a.initializeSystemInfo()
-	a.initializeDiskInfo()
-	a.initializeNetIoStats()
-	a.dockerManager = newDockerManager(a)
+	agent.initializeSystemInfo()
+	agent.initializeDiskInfo()
+	agent.initializeNetIoStats()
+	agent.dockerManager = newDockerManager(agent)
 
 	// initialize GPU manager
 	if gm, err := NewGPUManager(); err != nil {
 		slog.Debug("GPU", "err", err)
 	} else {
-		a.gpuManager = gm
+		agent.gpuManager = gm
 	}
 
 	// if debugging, print stats
-	if a.debug {
-		slog.Debug("Stats", "data", a.gatherStats())
+	if agent.debug {
+		slog.Debug("Stats", "data", agent.gatherStats())
 	}
 
-	a.startServer(pubKey, addr)
+	return agent
+}
+
+// GetEnv retrieves an environment variable with a "BESZEL_AGENT_" prefix, or falls back to the unprefixed key.
+func GetEnv(key string) (value string, exists bool) {
+	if value, exists = os.LookupEnv("BESZEL_AGENT_" + key); exists {
+		return value, exists
+	}
+	// Fallback to the old unprefixed key
+	return os.LookupEnv(key)
 }
 
 func (a *Agent) gatherStats() system.CombinedData {