Implement mdraid sysfs parsing

blockdevice/stats_test.go

@@ -73,7 +73,7 @@ func TestBlockDevice(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	expectedNumOfDevices := 2
+	expectedNumOfDevices := 8
 	if len(devices) != expectedNumOfDevices {
 		t.Fatalf(failMsgFormat, "Incorrect number of devices", expectedNumOfDevices, len(devices))
 	}
@@ -93,18 +93,18 @@ func TestBlockDevice(t *testing.T) {
 	if device0stats.WeightedIOTicks != 6088971 {
 		t.Errorf(failMsgFormat, "Incorrect time in queue", 6088971, device0stats.WeightedIOTicks)
 	}
-	device1stats, count, err := blockdevice.SysBlockDeviceStat(devices[1])
+	device7stats, count, err := blockdevice.SysBlockDeviceStat(devices[7])
 	if count != 15 {
 		t.Errorf(failMsgFormat, "Incorrect number of stats read", 15, count)
 	}
 	if err != nil {
 		t.Fatal(err)
 	}
-	if device1stats.WriteSectors != 286915323 {
-		t.Errorf(failMsgFormat, "Incorrect write merges", 286915323, device1stats.WriteSectors)
+	if device7stats.WriteSectors != 286915323 {
+		t.Errorf(failMsgFormat, "Incorrect write merges", 286915323, device7stats.WriteSectors)
 	}
-	if device1stats.DiscardTicks != 12 {
-		t.Errorf(failMsgFormat, "Incorrect discard ticks", 12, device1stats.DiscardTicks)
+	if device7stats.DiscardTicks != 12 {
+		t.Errorf(failMsgFormat, "Incorrect discard ticks", 12, device7stats.DiscardTicks)
 	}
 	blockQueueStatExpected := BlockQueueStats{
 		AddRandom:            1,
@@ -145,7 +145,7 @@ func TestBlockDevice(t *testing.T) {
 		WriteZeroesMaxBytes:  0,
 	}
 
-	blockQueueStat, err := blockdevice.SysBlockDeviceQueueStats(devices[1])
+	blockQueueStat, err := blockdevice.SysBlockDeviceQueueStats(devices[7])
 	if err != nil {
 		t.Fatal(err)
 	}

sysfs/mdraid.go

@@ -0,0 +1,160 @@
+// Copyright 2023 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.
+
+//go:build linux
+// +build linux
+
+package sysfs
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Mdraid holds info parsed from relevant files in the /sys/block/md*/md directory.
+type Mdraid struct {
+	Device          string            // Kernel device name of array.
+	Level           string            // mdraid level.
+	ArrayState      string            // State of the array.
+	MetadataVersion string            // mdraid metadata version.
+	Disks           uint64            // Number of devices in a fully functional array.
+	Components      []MdraidComponent // mdraid component devices.
+	UUID            string            // UUID of the array.
+
+	// The following item is only valid for raid0, 4, 5, 6 and 10.
+	ChunkSize uint64 // Chunk size
+
+	// The following items are only valid for raid1, 4, 5, 6 and 10.
+	DegradedDisks uint64  // Number of degraded disks in the array.
+	SyncAction    string  // Current sync action.
+	SyncCompleted float64 // Fraction (0-1) representing the completion status of current sync operation.
+}
+
+type MdraidComponent struct {
+	Device string // Kernel device name.
+	State  string // Current state of device.
+}
+
+// Mdraids gathers information and statistics about mdraid devices present. Based on upstream
+// kernel documentation https://docs.kernel.org/admin-guide/md.html.
+func (fs FS) Mdraids() ([]Mdraid, error) {
+	matches, err := filepath.Glob(fs.sys.Path("block/md*/md"))
+	if err != nil {
+		return nil, err
+	}
+
+	mdraids := make([]Mdraid, 0)
+
+	for _, m := range matches {
+		md := Mdraid{Device: filepath.Base(filepath.Dir(m))}
+		path := fs.sys.Path("block", md.Device, "md")
+
+		if val, err := util.SysReadFile(filepath.Join(path, "level")); err == nil {
+			md.Level = val
+		} else {
+			return mdraids, err
+		}
+
+		// Array state can be one of: clear, inactive, readonly, read-auto, clean, active,
+		// write-pending, active-idle.
+		if val, err := util.SysReadFile(filepath.Join(path, "array_state")); err == nil {
+			md.ArrayState = val
+		} else {
+			return mdraids, err
+		}
+
+		if val, err := util.SysReadFile(filepath.Join(path, "metadata_version")); err == nil {
+			md.MetadataVersion = val
+		} else {
+			return mdraids, err
+		}
+
+		if val, err := util.ReadUintFromFile(filepath.Join(path, "raid_disks")); err == nil {
+			md.Disks = val
+		} else {
+			return mdraids, err
+		}
+
+		if val, err := util.SysReadFile(filepath.Join(path, "uuid")); err == nil {
+			md.UUID = val
+		} else {
+			return mdraids, err
+		}
+
+		if devs, err := filepath.Glob(filepath.Join(path, "dev-*")); err == nil {
+			for _, dev := range devs {
+				comp := MdraidComponent{Device: strings.TrimPrefix(filepath.Base(dev), "dev-")}
+
+				// Component state can be a comma-separated list of: faulty, in_sync, writemostly,
+				// blocked, spare, write_error, want_replacement, replacement.
+				if val, err := util.SysReadFile(filepath.Join(dev, "state")); err == nil {
+					comp.State = val
+				} else {
+					return mdraids, err
+				}
+
+				md.Components = append(md.Components, comp)
+			}
+		} else {
+			return mdraids, err
+		}
+
+		switch md.Level {
+		case "raid0", "raid4", "raid5", "raid6", "raid10":
+			if val, err := util.ReadUintFromFile(filepath.Join(path, "chunk_size")); err == nil {
+				md.ChunkSize = val
+			} else {
+				return mdraids, err
+			}
+		}
+
+		switch md.Level {
+		case "raid1", "raid4", "raid5", "raid6", "raid10":
+			if val, err := util.ReadUintFromFile(filepath.Join(path, "degraded")); err == nil {
+				md.DegradedDisks = val
+			} else {
+				return mdraids, err
+			}
+
+			// Array sync action can be one of: resync, recover, idle, check, repair.
+			if val, err := util.SysReadFile(filepath.Join(path, "sync_action")); err == nil {
+				md.SyncAction = val
+			} else {
+				return mdraids, err
+			}
+
+			if val, err := util.SysReadFile(filepath.Join(path, "sync_completed")); err == nil {
+				if val != "none" {
+					var a, b uint64
+
+					// File contains two values representing the fraction of number of completed
+					// sectors divided by number of total sectors to process.
+					if _, err := fmt.Sscanf(val, "%d / %d", &a, &b); err == nil {
+						md.SyncCompleted = float64(a) / float64(b)
+					} else {
+						return mdraids, err
+					}
+				}
+			} else {
+				return mdraids, err
+			}
+		}
+
+		mdraids = append(mdraids, md)
+	}
+
+	return mdraids, nil
+}

sysfs/mdraid_test.go

@@ -0,0 +1,134 @@
+// Copyright 2023 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.
+
+//go:build linux
+// +build linux
+
+package sysfs
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestMdraidStats(t *testing.T) {
+	fs, err := NewFS(sysTestFixtures)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := fs.Mdraids()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := []Mdraid{
+		{
+			Device:          "md0",
+			Level:           "raid0",
+			ArrayState:      "clean",
+			MetadataVersion: "1.2",
+			Disks:           2,
+			Components: []MdraidComponent{
+				{Device: "sdg", State: "in_sync"},
+				{Device: "sdh", State: "in_sync"},
+			},
+			UUID:      "155f29ff-1716-4107-b362-52307ef86cac",
+			ChunkSize: 524288,
+		},
+		{
+			Device:          "md1",
+			Level:           "raid1",
+			ArrayState:      "clean",
+			MetadataVersion: "1.2",
+			Disks:           2,
+			Components: []MdraidComponent{
+				{Device: "sdi", State: "in_sync"},
+				{Device: "sdj", State: "in_sync"},
+			},
+			UUID:       "0fbf5f2c-add2-43c2-bd78-a4be3ab709ef",
+			SyncAction: "idle",
+		},
+		{
+			Device:          "md10",
+			Level:           "raid10",
+			ArrayState:      "clean",
+			MetadataVersion: "1.2",
+			Disks:           4,
+			Components: []MdraidComponent{
+				{Device: "sdu", State: "in_sync"},
+				{Device: "sdv", State: "in_sync"},
+				{Device: "sdw", State: "in_sync"},
+				{Device: "sdx", State: "in_sync"},
+			},
+			UUID:       "0c15f7e7-b159-4b1f-a5cd-a79b5c04b6f5",
+			ChunkSize:  524288,
+			SyncAction: "idle",
+		},
+		{
+			Device:          "md4",
+			Level:           "raid4",
+			ArrayState:      "clean",
+			MetadataVersion: "1.2",
+			Disks:           3,
+			Components: []MdraidComponent{
+				{Device: "sdk", State: "in_sync"},
+				{Device: "sdl", State: "in_sync"},
+				{Device: "sdm", State: "in_sync"},
+			},
+			UUID:       "67f415d5-2c0c-4b69-8e0d-7e20ef553457",
+			ChunkSize:  524288,
+			SyncAction: "idle",
+		},
+		{
+			Device:          "md5",
+			Level:           "raid5",
+			ArrayState:      "clean",
+			MetadataVersion: "1.2",
+			Disks:           3,
+			Components: []MdraidComponent{
+				{Device: "sdaa", State: "spare"},
+				{Device: "sdn", State: "in_sync"},
+				{Device: "sdo", State: "in_sync"},
+				{Device: "sdp", State: "faulty"},
+			},
+			UUID:          "7615b98d-f2ba-4d99-bee8-6202d8e130b9",
+			ChunkSize:     524288,
+			DegradedDisks: 1,
+			SyncAction:    "idle",
+		},
+		{
+			Device:          "md6",
+			Level:           "raid6",
+			ArrayState:      "active",
+			MetadataVersion: "1.2",
+			Disks:           4,
+			Components: []MdraidComponent{
+				{Device: "sdq", State: "in_sync"},
+				{Device: "sdr", State: "in_sync"},
+				{Device: "sds", State: "in_sync"},
+				{Device: "sdt", State: "spare"},
+			},
+			UUID:          "5f529b25-6efd-46e4-99a2-31f6f597be6b",
+			ChunkSize:     524288,
+			DegradedDisks: 1,
+			SyncAction:    "recover",
+			SyncCompleted: 0.7500458659491194,
+		},
+	}
+
+	if diff := cmp.Diff(want, got); diff != "" {
+		t.Fatalf("unexpected Mdraid (-want +got):\n%s", diff)
+	}
+}