fix: allow configuring powermode check to work better with SSDs

fixes #91

Signed-off-by: Robin Björklin <[email protected]>

main.go

@@ -14,6 +14,7 @@
 package main
 
 import (
+	"fmt"
 	"log/slog"
 	"net/http"
 	"os"
@@ -120,6 +121,9 @@ var (
 	smartctlFakeData = kingpin.Flag("smartctl.fake-data",
 		"The device to monitor (repeatable)",
 	).Default("false").Hidden().Bool()
+	smartctlPowerModeCheck = kingpin.Flag("smartctl.powermode-check",
+		"Whether or not to check powermode before fetching data",
+	).Default("standby").String()
 )
 
 // scanDevices uses smartctl to gather the list of available devices.
@@ -171,6 +175,15 @@ func buildDevicesFromFlag(devices []Device) []Device {
 	return devices
 }
 
+func validatePowerMode(mode string) error {
+	switch strings.ToLower(mode) {
+	case "never", "sleep", "standby", "idle":
+		return nil
+	default:
+		return fmt.Errorf("invalid power mode: %s. Must be one of: never, sleep, standby, idle", mode)
+	}
+}
+
 func main() {
 	metricsPath := kingpin.Flag(
 		"web.telemetry-path", "Path under which to expose metrics",
@@ -184,9 +197,12 @@ func main() {
 	kingpin.Parse()
 	logger := promslog.New(promslogConfig)
 
+	if err := validatePowerMode(*smartctlPowerModeCheck); err != nil {
+		logger.Error(err.Error())
+		os.Exit(1)
+	}
 	logger.Info("Starting smartctl_exporter", "version", version.Info())
 	logger.Info("Build context", "build_context", version.BuildContext())
-
 	var devices []Device
 
 	if len(*smartctlDevices) == 0 {

readjson.go

@@ -63,7 +63,7 @@ func readFakeSMARTctl(logger *slog.Logger, device Device) gjson.Result {
 // Get json from smartctl and parse it
 func readSMARTctl(logger *slog.Logger, device Device) (gjson.Result, bool) {
 	start := time.Now()
-	var smartctlArgs = []string{"--json", "--info", "--health", "--attributes", "--tolerance=verypermissive", "--nocheck=standby", "--format=brief", "--log=error", "--device=" + device.Type, device.Name}
+	var smartctlArgs = []string{"--json", "--info", "--health", "--attributes", "--tolerance=verypermissive", "--nocheck=" + *smartctlPowerModeCheck, "--format=brief", "--log=error", "--device=" + device.Type, device.Name}
 
 	logger.Debug("Calling smartctl with args", "args", strings.Join(smartctlArgs, " "))
 	out, err := exec.Command(*smartctlPath, smartctlArgs...).Output()