pagefile: BREAKING: move paging metrics from os to dedicated collector (click PR for more information) (#1735)

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

internal/collector/os/os.go

@@ -34,9 +34,14 @@ var ConfigDefaults = Config{}
 type Collector struct {
 	config Config
 
-	hostname         *prometheus.Desc
-	osInformation    *prometheus.Desc
-	pagingFreeBytes  *prometheus.Desc
+	hostname      *prometheus.Desc
+	osInformation *prometheus.Desc
+
+	// pagingFreeBytes
+	// Deprecated: Use windows_paging_free_bytes instead.
+	pagingFreeBytes *prometheus.Desc
+	// pagingLimitBytes
+	// Deprecated: Use windows_paging_total_bytes instead.
 	pagingLimitBytes *prometheus.Desc
 
 	// users
@@ -151,13 +156,13 @@ func (c *Collector) Build(logger *slog.Logger, _ *mi.Session) error {
 	)
 	c.pagingLimitBytes = prometheus.NewDesc(
 		prometheus.BuildFQName(types.Namespace, Name, "paging_limit_bytes"),
-		"OperatingSystem.SizeStoredInPagingFiles",
+		"Deprecated: Use windows_pagefile_limit_bytes instead.",
 		nil,
 		nil,
 	)
 	c.pagingFreeBytes = prometheus.NewDesc(
 		prometheus.BuildFQName(types.Namespace, Name, "paging_free_bytes"),
-		"OperatingSystem.FreeSpaceInPagingFiles",
+		"Deprecated: Use windows_pagefile_free_bytes instead.",
 		nil,
 		nil,
 	)

internal/collector/pagefile/const.go

@@ -0,0 +1,5 @@
+package pagefile
+
+const (
+	usage = "% Usage"
+)

internal/collector/pagefile/pagefile.go

@@ -0,0 +1,136 @@
+//go:build windows
+
+package pagefile
+
+import (
+	"fmt"
+	"log/slog"
+	"os"
+	"strings"
+
+	"github.com/alecthomas/kingpin/v2"
+	"github.com/prometheus-community/windows_exporter/internal/headers/psapi"
+	"github.com/prometheus-community/windows_exporter/internal/mi"
+	"github.com/prometheus-community/windows_exporter/internal/perfdata"
+	"github.com/prometheus-community/windows_exporter/internal/types"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const Name = "pagefile"
+
+type Config struct{}
+
+var ConfigDefaults = Config{}
+
+// A Collector is a Prometheus Collector for WMI metrics.
+type Collector struct {
+	config Config
+
+	perfDataCollector perfdata.Collector
+
+	pagingFreeBytes  *prometheus.Desc
+	pagingLimitBytes *prometheus.Desc
+}
+
+func New(config *Config) *Collector {
+	if config == nil {
+		config = &ConfigDefaults
+	}
+
+	c := &Collector{
+		config: *config,
+	}
+
+	return c
+}
+
+func NewWithFlags(_ *kingpin.Application) *Collector {
+	return &Collector{}
+}
+
+func (c *Collector) GetName() string {
+	return Name
+}
+
+func (c *Collector) GetPerfCounter(_ *slog.Logger) ([]string, error) {
+	return []string{}, nil
+}
+
+func (c *Collector) Close(_ *slog.Logger) error {
+	return nil
+}
+
+func (c *Collector) Build(_ *slog.Logger, _ *mi.Session) error {
+	counters := []string{
+		usage,
+	}
+
+	var err error
+
+	c.perfDataCollector, err = perfdata.NewCollector(perfdata.V2, "Paging File", perfdata.AllInstances, counters)
+	if err != nil {
+		return fmt.Errorf("failed to create Paging File collector: %w", err)
+	}
+
+	c.pagingLimitBytes = prometheus.NewDesc(
+		prometheus.BuildFQName(types.Namespace, Name, "limit_bytes"),
+		"Number of bytes that can be stored in the operating system paging files. 0 (zero) indicates that there are no paging files",
+		[]string{"file"},
+		nil,
+	)
+
+	c.pagingFreeBytes = prometheus.NewDesc(
+		prometheus.BuildFQName(types.Namespace, Name, "free_bytes"),
+		"Number of bytes that can be mapped into the operating system paging files without causing any other pages to be swapped out",
+		[]string{"file"},
+		nil,
+	)
+
+	return nil
+}
+
+// Collect sends the metric values for each metric
+// to the provided prometheus Metric channel.
+func (c *Collector) Collect(_ *types.ScrapeContext, _ *slog.Logger, ch chan<- prometheus.Metric) error {
+	return c.collectPaging(ch)
+}
+
+func (c *Collector) collectPaging(ch chan<- prometheus.Metric) error {
+	data, err := c.perfDataCollector.Collect()
+	if err != nil {
+		return fmt.Errorf("failed to collect Paging File metrics: %w", err)
+	}
+
+	gpi, err := psapi.GetPerformanceInfo()
+	if err != nil {
+		return err
+	}
+
+	for fileName, pageFile := range data {
+		fileString := strings.ReplaceAll(fileName, `\??\`, "")
+		file, err := os.Stat(fileString)
+
+		var fileSize float64
+
+		// For unknown reasons, Windows doesn't always create a page file. Continue collection rather than aborting.
+		if err == nil {
+			fileSize = float64(file.Size())
+		}
+
+		ch <- prometheus.MustNewConstMetric(
+			c.pagingFreeBytes,
+			prometheus.GaugeValue,
+			fileSize-(pageFile[usage].FirstValue*float64(gpi.PageSize)),
+			fileString,
+		)
+
+		ch <- prometheus.MustNewConstMetric(
+			c.pagingLimitBytes,
+			prometheus.GaugeValue,
+			fileSize,
+			fileString,
+		)
+	}
+
+	return nil
+}

internal/collector/pagefile/pagefile_test.go

@@ -0,0 +1,16 @@
+package pagefile_test
+
+import (
+	"testing"
+
+	"github.com/prometheus-community/windows_exporter/internal/collector/pagefile"
+	"github.com/prometheus-community/windows_exporter/internal/testutils"
+)
+
+func BenchmarkCollector(b *testing.B) {
+	testutils.FuncBenchmarkCollector(b, pagefile.Name, pagefile.NewWithFlags)
+}
+
+func TestCollector(t *testing.T) {
+	testutils.TestCollector(t, pagefile.New, nil)
+}

internal/perfdata/v2/collector.go

@@ -5,6 +5,7 @@ package v2
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"strings"
 	"unsafe"
 
@@ -14,9 +15,10 @@ import (
 )
 
 type Collector struct {
-	object   string
-	counters map[string]Counter
-	handle   pdhQueryHandle
+	object                string
+	counters              map[string]Counter
+	handle                pdhQueryHandle
+	totalCounterRequested bool
 }
 
 type Counter struct {
@@ -39,9 +41,10 @@ func NewCollector(object string, instances []string, counters []string) (*Collec
 	}
 
 	collector := &Collector{
-		object:   object,
-		counters: make(map[string]Counter, len(counters)),
-		handle:   handle,
+		object:                object,
+		counters:              make(map[string]Counter, len(counters)),
+		handle:                handle,
+		totalCounterRequested: slices.Contains(instances, "_Total"),
 	}
 
 	for _, counterName := range counters {
@@ -166,12 +169,10 @@ func (c *Collector) Collect() (map[string]map[string]perftypes.CounterValues, er
 				metricType = prometheus.GaugeValue
 			}
 
-			_, isTotalCounterRequests := c.counters["_Total"]
-
 			for _, item := range items {
 				if item.RawValue.CStatus == PdhCstatusValidData || item.RawValue.CStatus == PdhCstatusNewData {
 					instanceName := windows.UTF16PtrToString(item.SzName)
-					if strings.HasSuffix(instanceName, "_Total") && !isTotalCounterRequests {
+					if strings.HasSuffix(instanceName, "_Total") && !c.totalCounterRequested {
 						continue
 					}