Add support for device types and predictable device paths (rebased) (#257)

* Add better error logging on smartctl exec failure

We will now log a warning if smartctl path passed via command line is invalid.

Signed-off-by: Piotr Dobrowolski <admin@tastycode.pl>
(cherry picked from commit 1c9c6943e8)

* Add support for autoscan device types and predictable device paths

This adds a new command line option allowing for customization of
autodetected device types and enables use of special "by-id" device type
that forces use of predictable device paths (/dev/disk/by-id/...)

Relevant change to device name parsing regular expression is included
now, so predictable device paths are now also usable when directly
specified.

Signed-off-by: Piotr Dobrowolski <admin@tastycode.pl>
(cherry picked from commit 4c5f721e11)

Conflicts:
  - file: 'readjson.go'
    comment: 'manually resolve new logger issues'

* Rework device label, fix SATA discovery, per-device type specification

Signed-off-by: Piotr Dobrowolski <admin@tastycode.pl>
(cherry picked from commit 319184ce66)

Conflicts:
  - file: 'main.go'
    comment: 'manually resolve new logger issues'
  - file: 'readjson.go'
    comment: 'manually resolve new logger issues'

---------

Co-authored-by: Piotr Dobrowolski <admin@tastycode.pl>

main.go

@@ -34,9 +34,13 @@ import (
 
 // Device
 type Device struct {
-	Name      string `json:"name"`
+	Name  string
-	Info_Name string `json:"info_name"`
+	Type  string
-	Type      string `json:"type"`
+	Label string
+}
+
+func (d Device) String() string {
+	return d.Name + ";" + d.Type + " (" + d.Label + ")"
 }
 
 // SMARTctlManagerCollector implements the Collector interface.
@@ -80,6 +84,7 @@ func (i *SMARTctlManagerCollector) RescanForDevices() {
 		time.Sleep(*smartctlRescanInterval)
 		i.logger.Info("Rescanning for devices")
 		devices := scanDevices(i.logger)
+		devices = buildDevicesFromFlag(devices)
 		i.mutex.Lock()
 		i.Devices = devices
 		i.mutex.Unlock()
@@ -96,8 +101,9 @@ var (
 	smartctlRescanInterval = kingpin.Flag("smartctl.rescan",
 		"The interval between rescanning for new/disappeared devices. If the interval is smaller than 1s no rescanning takes place. If any devices are configured with smartctl.device also no rescanning takes place.",
 	).Default("10m").Duration()
+	smartctlScan    = kingpin.Flag("smartctl.scan", "Enable scanning. This is a default if no devices are specified").Default("false").Bool()
 	smartctlDevices = kingpin.Flag("smartctl.device",
-		"The device to monitor (repeatable)",
+		"The device to monitor. Device type can be specified after a semicolon, eg. '/dev/bus/0;megaraid,1' (repeatable)",
 	).Strings()
 	smartctlDeviceExclude = kingpin.Flag(
 		"smartctl.device-exclude",
@@ -107,6 +113,10 @@ var (
 		"smartctl.device-include",
 		"Regexp of devices to exclude from automatic scanning. (mutually exclusive to device-exclude)",
 	).Default("").String()
+	smartctlScanDeviceTypes = kingpin.Flag(
+		"smartctl.scan-device-type",
+		"Device type to use during automatic scan. Special by-id value forces predictable device names. (repeatable)",
+	).Strings()
 	smartctlFakeData = kingpin.Flag("smartctl.fake-data",
 		"The device to monitor (repeatable)",
 	).Default("false").Hidden().Bool()
@@ -120,15 +130,23 @@ func scanDevices(logger *slog.Logger) []Device {
 	scanDevices := json.Get("devices").Array()
 	var scanDeviceResult []Device
 	for _, d := range scanDevices {
-		deviceName := extractDiskName(strings.TrimSpace(d.Get("info_name").String()))
+		deviceName := d.Get("name").String()
-		if filter.ignored(deviceName) {
+		deviceType := d.Get("type").String()
-			logger.Info("Ignoring device", "name", deviceName)
+
+		// SATA devices are reported as SCSI during scan - fallback to auto scraping
+		if deviceType == "scsi" {
+			deviceType = "auto"
+		}
+
+		deviceLabel := buildDeviceLabel(deviceName, deviceType)
+		if filter.ignored(deviceLabel) {
+			logger.Info("Ignoring device", "name", deviceLabel)
 		} else {
-			logger.Info("Found device", "name", deviceName)
+			logger.Info("Found device", "name", deviceLabel)
 			device := Device{
-				Name:      d.Get("name").String(),
+				Name:  deviceName,
-				Info_Name: deviceName,
+				Type:  deviceType,
-				Type:      d.Get("type").String(),
+				Label: deviceLabel,
 			}
 			scanDeviceResult = append(scanDeviceResult, device)
 		}
@@ -136,18 +154,21 @@ func scanDevices(logger *slog.Logger) []Device {
 	return scanDeviceResult
 }
 
-func filterDevices(logger *slog.Logger, devices []Device, filters []string) []Device {
+func buildDevicesFromFlag(devices []Device) []Device {
-	var filtered []Device
+	// TODO: deduplication?
-	for _, d := range devices {
+	for _, device := range *smartctlDevices {
-		for _, filter := range filters {
+		deviceName, deviceType, _ := strings.Cut(device, ";")
-			logger.Debug("filterDevices", "device", d.Info_Name, "filter", filter)
+		if deviceType == "" {
-			if strings.Contains(d.Info_Name, filter) {
+			deviceType = "auto"
-				filtered = append(filtered, d)
-				break
-			}
 		}
+
+		devices = append(devices, Device{
+			Name:  deviceName,
+			Type:  deviceType,
+			Label: buildDeviceLabel(deviceName, deviceType),
+		})
 	}
-	return filtered
+	return devices
 }
 
 func main() {
@@ -167,11 +188,19 @@ func main() {
 	logger.Info("Build context", "build_context", version.BuildContext())
 
 	var devices []Device
-	devices = scanDevices(logger)
+
-	logger.Info("Number of devices found", "count", len(devices))
+	if len(*smartctlDevices) == 0 {
+		*smartctlScan = true
+	}
+
+	if *smartctlScan {
+		devices = scanDevices(logger)
+		logger.Info("Number of devices found", "count", len(devices))
+	}
+
 	if len(*smartctlDevices) > 0 {
 		logger.Info("Devices specified", "devices", strings.Join(*smartctlDevices, ", "))
-		devices = filterDevices(logger, devices, *smartctlDevices)
+		devices = buildDevicesFromFlag(devices)
 		logger.Info("Devices filtered", "count", len(devices))
 	}
 
@@ -180,7 +209,7 @@ func main() {
 		logger:  logger,
 	}
 
-	if *smartctlRescanInterval >= 1*time.Second {
+	if *smartctlScan && *smartctlRescanInterval >= 1*time.Second {
 		logger.Info("Start background scan process")
 		logger.Info("Rescanning for devices every", "rescanInterval", *smartctlRescanInterval)
 		go collector.RescanForDevices()

readjson.go

@@ -63,22 +63,29 @@ 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()
-	out, err := exec.Command(*smartctlPath, "--json", "--info", "--health", "--attributes", "--tolerance=verypermissive", "--nocheck=standby", "--format=brief", "--log=error", "--device="+device.Type, device.Name).Output()
+	var smartctlArgs = []string{"--json", "--info", "--health", "--attributes", "--tolerance=verypermissive", "--nocheck=standby", "--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()
 	if err != nil {
-		logger.Warn("S.M.A.R.T. output reading", "err", err, "device", device.Info_Name)
+		logger.Warn("S.M.A.R.T. output reading", "err", err, "device", device)
 	}
 	// Accommodate a smartmontools pre-7.3 bug
 	cleaned_out := strings.TrimPrefix(string(out), "  Pending defect count:")
 	json := parseJSON(cleaned_out)
 	rcOk := resultCodeIsOk(logger, device, json.Get("smartctl.exit_status").Int())
 	jsonOk := jsonIsOk(logger, json)
-	logger.Debug("Collected S.M.A.R.T. json data", "device", device.Info_Name, "duration", time.Since(start))
+	logger.Debug("Collected S.M.A.R.T. json data", "device", device, "duration", time.Since(start))
 	return json, rcOk && jsonOk
 }
 
 func readSMARTctlDevices(logger *slog.Logger) gjson.Result {
 	logger.Debug("Scanning for devices")
-	out, err := exec.Command(*smartctlPath, "--json", "--scan").Output()
+	var scanArgs []string = []string{"--json", "--scan"}
+	for _, d := range *smartctlScanDeviceTypes {
+		scanArgs = append(scanArgs, "--device", d)
+	}
+	out, err := exec.Command(*smartctlPath, scanArgs...).Output()
 	if exiterr, ok := err.(*exec.ExitError); ok {
 		logger.Debug("Exit Status", "exit_code", exiterr.ExitCode())
 		// The smartctl command returns 2 if devices are sleeping, ignore this error.
@@ -86,6 +93,9 @@ func readSMARTctlDevices(logger *slog.Logger) gjson.Result {
 			logger.Warn("S.M.A.R.T. output reading error", "err", err)
 			return gjson.Result{}
 		}
+	} else if err != nil {
+		logger.Warn("S.M.A.R.T. output reading error", "err", err)
+		return gjson.Result{}
 	}
 	return parseJSON(string(out))
 }
@@ -103,7 +113,7 @@ func readData(logger *slog.Logger, device Device) gjson.Result {
 			jsonCache.Store(device, JSONCache{JSON: json, LastCollect: time.Now()})
 			j, found := jsonCache.Load(device)
 			if !found {
-				logger.Warn("device not found", "device", device.Info_Name)
+				logger.Warn("device not found", "device", device)
 			}
 			return j.(JSONCache).JSON
 		}
@@ -118,30 +128,30 @@ func resultCodeIsOk(logger *slog.Logger, device Device, SMARTCtlResult int64) bo
 	if SMARTCtlResult > 0 {
 		b := SMARTCtlResult
 		if (b & 1) != 0 {
-			logger.Error("Command line did not parse", "device", device.Info_Name)
+			logger.Error("Command line did not parse", "device", device)
 			result = false
 		}
 		if (b & (1 << 1)) != 0 {
-			logger.Error("Device open failed, device did not return an IDENTIFY DEVICE structure, or device is in a low-power mode", "device", device.Info_Name)
+			logger.Error("Device open failed, device did not return an IDENTIFY DEVICE structure, or device is in a low-power mode", "device", device)
 			result = false
 		}
 		if (b & (1 << 2)) != 0 {
-			logger.Warn("Some SMART or other ATA command to the disk failed, or there was a checksum error in a SMART data structure", "device", device.Info_Name)
+			logger.Warn("Some SMART or other ATA command to the disk failed, or there was a checksum error in a SMART data structure", "device", device)
 		}
 		if (b & (1 << 3)) != 0 {
-			logger.Warn("SMART status check returned 'DISK FAILING'", "device", device.Info_Name)
+			logger.Warn("SMART status check returned 'DISK FAILING'", "device", device)
 		}
 		if (b & (1 << 4)) != 0 {
-			logger.Warn("We found prefail Attributes <= threshold", "device", device.Info_Name)
+			logger.Warn("We found prefail Attributes <= threshold", "device", device)
 		}
 		if (b & (1 << 5)) != 0 {
-			logger.Warn("SMART status check returned 'DISK OK' but we found that some (usage or prefail) Attributes have been <= threshold at some time in the past", "device", device.Info_Name)
+			logger.Warn("SMART status check returned 'DISK OK' but we found that some (usage or prefail) Attributes have been <= threshold at some time in the past", "device", device)
 		}
 		if (b & (1 << 6)) != 0 {
-			logger.Warn("The device error log contains records of errors", "device", device.Info_Name)
+			logger.Warn("The device error log contains records of errors", "device", device)
 		}
 		if (b & (1 << 7)) != 0 {
-			logger.Warn("The device self-test log contains records of errors. [ATA only] Failed self-tests outdated by a newer successful extended self-test are ignored", "device", device.Info_Name)
+			logger.Warn("The device self-test log contains records of errors. [ATA only] Failed self-tests outdated by a newer successful extended self-test are ignored", "device", device)
 		}
 	}
 	return result

smartctl.go

@@ -42,28 +42,16 @@ type SMARTctl struct {
 	device SMARTDevice
 }
 
-func extractDiskName(input string) string {
+func buildDeviceLabel(inputName string, inputType string) string {
-	re := regexp.MustCompile(`^(?:/dev/(?P<bus_name>\S+)/(?P<bus_num>\S+)\s\[|/dev/|\[)(?:\s\[|)(?P<disk>[a-z0-9_]+)(?:\].*|)$`)
+	// Strip /dev prefix and replace / with _ (/dev/bus/0 becomes bus_0, /dev/disk/by-id/abcd becomes abcd)
-	match := re.FindStringSubmatch(input)
+	devReg := regexp.MustCompile(`^/dev/(?:disk/by-id/|disk/by-path/|)`)
+	deviceName := strings.ReplaceAll(devReg.ReplaceAllString(inputName, ""), "/", "_")
 
-	if len(match) > 0 {
+	if strings.Contains(inputType, ",") {
-		busNameIndex := re.SubexpIndex("bus_name")
+		return deviceName + "_" + strings.ReplaceAll(inputType, ",", "_")
-		busNumIndex := re.SubexpIndex("bus_num")
-		diskIndex := re.SubexpIndex("disk")
-		var name []string
-		if busNameIndex != -1 && match[busNameIndex] != "" {
-			name = append(name, match[busNameIndex])
-		}
-		if busNumIndex != -1 && match[busNumIndex] != "" {
-			name = append(name, match[busNumIndex])
-		}
-		if diskIndex != -1 && match[diskIndex] != "" {
-			name = append(name, match[diskIndex])
-		}
-
-		return strings.Join(name, "_")
 	}
-	return ""
+
+	return deviceName
 }
 
 // NewSMARTctl is smartctl constructor
@@ -84,7 +72,7 @@ func NewSMARTctl(logger *slog.Logger, json gjson.Result, ch chan<- prometheus.Me
 		json:   json,
 		logger: logger,
 		device: SMARTDevice{
-			device:     extractDiskName(strings.TrimSpace(json.Get("device.info_name").String())),
+			device:     buildDeviceLabel(json.Get("device.name").String(), json.Get("device.type").String()),
 			serial:     strings.TrimSpace(json.Get("serial_number").String()),
 			family:     strings.TrimSpace(GetStringIfExists(json, "model_family", "unknown")),
 			model:      strings.TrimSpace(model_name),

smartctl_test.go

@@ -0,0 +1,44 @@
+// Copyright 2024 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"testing"
+)
+
+func TestBuildDeviceLabel(t *testing.T) {
+	tests := []struct {
+		deviceName    string
+		deviceType    string
+		expectedLabel string
+	}{
+		{"/dev/bus/0", "megaraid,1", "bus_0_megaraid_1"},
+		{"/dev/sda", "auto", "sda"},
+		{"/dev/disk/by-id/ata-CT500MX500SSD1_ABCDEFGHIJ", "auto", "ata-CT500MX500SSD1_ABCDEFGHIJ"},
+		// Some cases extracted from smartctl docs. Are these the prettiest?
+		// Probably not. Are they unique enough. Definitely.
+		{"/dev/sg1", "cciss,1", "sg1_cciss_1"},
+		{"/dev/bsg/sssraid0", "sssraid,0,1", "bsg_sssraid0_sssraid_0_1"},
+		{"/dev/cciss/c0d0", "cciss,0", "cciss_c0d0_cciss_0"},
+		{"/dev/sdb", "aacraid,1,0,4", "sdb_aacraid_1_0_4"},
+		{"/dev/twl0", "3ware,1", "twl0_3ware_1"},
+	}
+
+	for _, test := range tests {
+		result := buildDeviceLabel(test.deviceName, test.deviceType)
+		if result != test.expectedLabel {
+			t.Errorf("deviceName=%v deviceType=%v expected=%v result=%v", test.deviceName, test.deviceType, test.expectedLabel, result)
+		}
+	}
+}