fix: use log.file=eventlog as default value, if running as windows service (#1771)

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

.run/all.run.xml

@@ -2,7 +2,7 @@
   <configuration default="false" name="all" type="GoApplicationRunConfiguration" factoryName="Go Application" folderName="run">
     <module name="windows_exporter" />
     <working_directory value="$PROJECT_DIR$" />
-    <parameters value="--web.listen-address=127.0.0.1:9182 --log.level=debug --collectors.enabled=ad,adcs,adfs,cache,container,cpu,cpu_info,cs,dfsr,dhcp,diskdrive,dns,exchange,filetime,fsrmquota,hyperv,iis,license,logical_disk,logon,memory,mscluster,msmq,mssql,net,netframework,nps,os,pagefile,perfdata,physical_disk,printer,process,remote_fx,scheduled_task,service,smb,smbclient,smtp,system,tcp,terminal_services,textfile,thermalzone,time,udp,update,vmware" />
+    <parameters value="--web.listen-address=127.0.0.1:9182 --log.level=info --collectors.enabled=ad,adcs,adfs,cache,container,cpu,cpu_info,cs,dfsr,dhcp,diskdrive,dns,exchange,filetime,fsrmquota,hyperv,iis,license,logical_disk,logon,memory,mscluster,msmq,mssql,net,netframework,nps,os,pagefile,perfdata,physical_disk,printer,process,remote_fx,scheduled_task,service,smb,smbclient,smtp,system,tcp,terminal_services,thermalzone,time,udp,update,vmware --debug.enabled" />
     <sudo value="true" />
     <kind value="PACKAGE" />
     <package value="github.com/prometheus-community/windows_exporter/cmd/windows_exporter" />

README.md

@@ -199,6 +199,14 @@ Windows Server 2012 and 2012R2 are supported as best-effort only, but not guaran
 
 The prometheus metrics will be exposed on [localhost:9182](http://localhost:9182)
 
+### HTTP Endpoints
+
+windows_exporter provides the following HTTP endpoints:
+
+* `/metrics`: Exposes metrics in the [Prometheus text format](https://prometheus.io/docs/instrumenting/exposition_formats/).
+* `/health`: Returns 200 OK when the exporter is running.
+* `/debug/pprof/`: Exposes the [pprof](https://golang.org/pkg/net/http/pprof/) endpoints. Only, if `--debug.enabled` is set.
+
 ## Examples
 
 ### Enable only service collector and specify a custom query

cmd/windows_exporter/main.go

@@ -87,10 +87,6 @@ func run() int {
 			"web.disable-exporter-metrics",
 			"Exclude metrics about the exporter itself (promhttp_*, process_*, go_*).",
 		).Bool()
-		maxRequests = app.Flag(
-			"telemetry.max-requests",
-			"Maximum number of concurrent requests. 0 to disable.",
-		).Default("5").Int()
 		enabledCollectors = app.Flag(
 			"collectors.enabled",
 			"Comma-separated list of collectors to use. Use '[defaults]' as a placeholder for all the collectors enabled by default.").
@@ -109,7 +105,14 @@ func run() int {
 		).Default("normal").String()
 	)
 
-	logConfig := &log.Config{}
+	logFile := &log.AllowedFile{}
+
+	_ = logFile.Set("stdout")
+	if windowsservice.IsService {
+		_ = logFile.Set("eventlog")
+	}
+
+	logConfig := &log.Config{File: logFile}
 	flag.AddFlags(app, logConfig)
 
 	app.Version(version.Print("windows_exporter"))
@@ -220,7 +223,6 @@ func run() int {
 	mux.Handle("GET "+*metricsPath, httphandler.New(logger, collectors, &httphandler.Options{
 		DisableExporterMetrics: *disableExporterMetrics,
 		TimeoutMargin:          *timeoutMargin,
-		MaxRequests:            *maxRequests,
 	}))
 
 	if *debugEnabled {

installer/files.wxs

@@ -13,8 +13,8 @@
   ~ limitations under the License.
   -->
 
-<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs"
-     xmlns:util="http://wixtoolset.org/schemas/v4/wxs/util">
+<Wix xmlns:util="http://wixtoolset.org/schemas/v4/wxs/util"
+     xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <Fragment>
         <DirectoryRef Id="APPLICATIONFOLDER">
             <Component Transitive="yes">
@@ -28,7 +28,7 @@
                     Start="auto"
                     Type="ownProcess"
                     Vital="yes"
-                    Arguments="--log.file eventlog [ConfigFileFlag] [CollectorsFlag] [ListenFlag] [MetricsPathFlag] [TextfileDirsFlag] [ExtraFlags]">
+                    Arguments="[ConfigFileFlag] [CollectorsFlag] [ListenFlag] [MetricsPathFlag] [TextfileDirsFlag] [ExtraFlags]">
                     <util:ServiceConfig
                         ResetPeriodInDays="1"
                         FirstFailureActionType="restart"

installer/main.wxs

@@ -24,9 +24,9 @@
   ~ limitations under the License.
   -->
 
-<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs"
-     xmlns:fw="http://wixtoolset.org/schemas/v4/wxs/firewall"
-     xmlns:ui="http://wixtoolset.org/schemas/v4/wxs/ui">
+<Wix xmlns:fw="http://wixtoolset.org/schemas/v4/wxs/firewall"
+     xmlns:ui="http://wixtoolset.org/schemas/v4/wxs/ui"
+     xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <Package UpgradeCode="66a6eb5b-1fc2-4b14-a362-5ceec6413308" Name="$(var.ProductName)" Version="$(var.Version)"
              Manufacturer="prometheus-community" Language="1033" Scope="perMachine">
         <SummaryInformation Manufacturer="prometheus-community" Description="$(var.ProductName) $(var.Version) installer" />

internal/httphandler/httphandler.go

@@ -36,7 +36,7 @@ var _ http.Handler = (*MetricsHTTPHandler)(nil)
 const defaultScrapeTimeout = 10.0
 
 type MetricsHTTPHandler struct {
-	metricCollectors *collector.MetricCollectors
+	metricCollectors *collector.Collection
 	// exporterMetricsRegistry is a separate registry for the metrics about
 	// the exporter itself.
 	exporterMetricsRegistry *prometheus.Registry
@@ -49,15 +49,13 @@ type MetricsHTTPHandler struct {
 type Options struct {
 	DisableExporterMetrics bool
 	TimeoutMargin          float64
-	MaxRequests            int
 }
 
-func New(logger *slog.Logger, metricCollectors *collector.MetricCollectors, options *Options) *MetricsHTTPHandler {
+func New(logger *slog.Logger, metricCollectors *collector.Collection, options *Options) *MetricsHTTPHandler {
 	if options == nil {
 		options = &Options{
 			DisableExporterMetrics: false,
 			TimeoutMargin:          0.5,
-			MaxRequests:            5,
 		}
 	}
 
@@ -65,7 +63,9 @@ func New(logger *slog.Logger, metricCollectors *collector.MetricCollectors, opti
 		metricCollectors: metricCollectors,
 		logger:           logger,
 		options:          *options,
-		concurrencyCh:    make(chan struct{}, options.MaxRequests),
+
+		// We are expose metrics directly from the memory region of the Win32 API. We should not allow more than one request at a time.
+		concurrencyCh: make(chan struct{}, 1),
 	}
 
 	if !options.DisableExporterMetrics {
@@ -126,82 +126,48 @@ func (c *MetricsHTTPHandler) getScrapeTimeout(logger *slog.Logger, r *http.Reque
 
 func (c *MetricsHTTPHandler) handlerFactory(logger *slog.Logger, scrapeTimeout time.Duration, requestedCollectors []string) (http.Handler, error) {
 	reg := prometheus.NewRegistry()
-
-	var metricCollectors *collector.MetricCollectors
-	if len(requestedCollectors) == 0 {
-		metricCollectors = c.metricCollectors
-	} else {
-		filteredCollectors := make(collector.Map)
-
-		for _, name := range requestedCollectors {
-			metricCollector, ok := c.metricCollectors.Collectors[name]
-			if !ok {
-				return nil, fmt.Errorf("couldn't find collector %s", name)
-			}
-
-			filteredCollectors[name] = metricCollector
-		}
-
-		metricCollectors = &collector.MetricCollectors{
-			Collectors:       filteredCollectors,
-			MISession:        c.metricCollectors.MISession,
-			PerfCounterQuery: c.metricCollectors.PerfCounterQuery,
-		}
-	}
-
 	reg.MustRegister(version.NewCollector("windows_exporter"))
 
-	if err := reg.Register(metricCollectors.NewPrometheusCollector(scrapeTimeout, c.logger)); err != nil {
+	collectionHandler, err := c.metricCollectors.NewHandler(scrapeTimeout, c.logger, requestedCollectors)
+	if err != nil {
+		return nil, fmt.Errorf("couldn't create collector handler: %w", err)
+	}
+
+	if err := reg.Register(collectionHandler); err != nil {
 		return nil, fmt.Errorf("couldn't register Prometheus collector: %w", err)
 	}
 
-	var handler http.Handler
+	var regHandler http.Handler
 	if c.exporterMetricsRegistry != nil {
-		handler = promhttp.HandlerFor(
+		regHandler = promhttp.HandlerFor(
 			prometheus.Gatherers{c.exporterMetricsRegistry, reg},
 			promhttp.HandlerOpts{
 				ErrorLog:            slog.NewLogLogger(logger.Handler(), slog.LevelError),
 				ErrorHandling:       promhttp.ContinueOnError,
-				MaxRequestsInFlight: c.options.MaxRequests,
+				MaxRequestsInFlight: 1,
 				Registry:            c.exporterMetricsRegistry,
+				EnableOpenMetrics:   true,
+				ProcessStartTime:    c.metricCollectors.GetStartTime(),
 			},
 		)
 
 		// Note that we have to use h.exporterMetricsRegistry here to
 		// use the same promhttp metrics for all expositions.
-		handler = promhttp.InstrumentMetricHandler(
-			c.exporterMetricsRegistry, handler,
+		regHandler = promhttp.InstrumentMetricHandler(
+			c.exporterMetricsRegistry, regHandler,
 		)
 	} else {
-		handler = promhttp.HandlerFor(
+		regHandler = promhttp.HandlerFor(
 			reg,
 			promhttp.HandlerOpts{
 				ErrorLog:            slog.NewLogLogger(logger.Handler(), slog.LevelError),
 				ErrorHandling:       promhttp.ContinueOnError,
-				MaxRequestsInFlight: c.options.MaxRequests,
+				MaxRequestsInFlight: 1,
+				EnableOpenMetrics:   true,
+				ProcessStartTime:    c.metricCollectors.GetStartTime(),
 			},
 		)
 	}
 
-	return c.withConcurrencyLimit(handler.ServeHTTP), nil
-}
-
-func (c *MetricsHTTPHandler) withConcurrencyLimit(next http.HandlerFunc) http.HandlerFunc {
-	if c.options.MaxRequests <= 0 {
-		return next
-	}
-
-	return func(w http.ResponseWriter, r *http.Request) {
-		select {
-		case c.concurrencyCh <- struct{}{}:
-			defer func() { <-c.concurrencyCh }()
-		default:
-			w.WriteHeader(http.StatusServiceUnavailable)
-			_, _ = w.Write([]byte("Too many concurrent requests"))
-
-			return
-		}
-
-		next(w, r)
-	}
+	return regHandler, nil
 }

internal/log/flag/flag.go

@@ -34,6 +34,9 @@ func AddFlags(a *kingpin.Application, config *log.Config) {
 	config.Config = new(promslog.Config)
 	flag.AddFlags(a, config.Config)
 
-	config.File = &log.AllowedFile{}
-	a.Flag(FileFlagName, FileFlagHelp).Default("stderr").SetValue(config.File)
+	if config.File == nil {
+		config.File = &log.AllowedFile{}
+	}
+
+	a.Flag(FileFlagName, FileFlagHelp).Default(config.File.String()).SetValue(config.File)
 }

internal/log/logger.go

@@ -34,6 +34,10 @@ type AllowedFile struct {
 }
 
 func (f *AllowedFile) String() string {
+	if f == nil {
+		return ""
+	}
+
 	return f.s
 }
 

internal/perfdata/collector.go

@@ -193,6 +193,13 @@ func (c *Collector) Collect() (CounterValues, error) {
 }
 
 func (c *Collector) collectRoutine() {
+	var (
+		itemCount   uint32
+		bytesNeeded uint32
+	)
+
+	buf := make([]byte, 1)
+
 	for range c.collectCh {
 		if ret := PdhCollectQueryData(c.handle); ret != ErrorSuccess {
 			c.counterValuesCh <- nil
@@ -207,25 +214,24 @@ func (c *Collector) collectRoutine() {
 			for _, counter := range c.counters {
 				for _, instance := range counter.Instances {
 					// Get the info with the current buffer size
-					var itemCount uint32
+					bytesNeeded = uint32(cap(buf))
 
-					// Get the info with the current buffer size
-					bufLen := uint32(0)
+					for {
+						ret := PdhGetRawCounterArray(instance, &bytesNeeded, &itemCount, &buf[0])
 
-					ret := PdhGetRawCounterArray(instance, &bufLen, &itemCount, nil)
-					if ret != PdhMoreData {
-						return nil, fmt.Errorf("PdhGetRawCounterArray: %w", NewPdhError(ret))
-					}
+						if ret == ErrorSuccess {
+							break
+						}
 
-					buf := make([]byte, bufLen)
-
-					ret = PdhGetRawCounterArray(instance, &bufLen, &itemCount, &buf[0])
-					if ret != ErrorSuccess {
-						if err := NewPdhError(ret); !isKnownCounterDataError(err) {
+						if err := NewPdhError(ret); ret != PdhMoreData && !isKnownCounterDataError(err) {
 							return nil, fmt.Errorf("PdhGetRawCounterArray: %w", err)
 						}
 
-						continue
+						if bytesNeeded <= uint32(cap(buf)) {
+							return nil, fmt.Errorf("PdhGetRawCounterArray reports buffer too small (%d), but buffer is large enough (%d): %w", uint32(cap(buf)), bytesNeeded, NewPdhError(ret))
+						}
+
+						buf = make([]byte, bytesNeeded)
 					}
 
 					items := unsafe.Slice((*PdhRawCounterItem)(unsafe.Pointer(&buf[0])), itemCount)

internal/perfdata/collector_bench_test.go

@@ -61,4 +61,6 @@ func BenchmarkTestCollector(b *testing.B) {
 	}
 
 	performanceData.Close()
+
+	b.ReportAllocs()
 }

pkg/collector/collect.go

@@ -11,8 +11,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build windows
-
 package collector
 
 import (
@@ -27,26 +25,10 @@ import (
 
 	"github.com/prometheus-community/windows_exporter/internal/mi"
 	"github.com/prometheus-community/windows_exporter/internal/perfdata"
-	types "github.com/prometheus-community/windows_exporter/internal/types"
+	"github.com/prometheus-community/windows_exporter/internal/types"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
-// Interface guard.
-var _ prometheus.Collector = (*Prometheus)(nil)
-
-// Prometheus implements prometheus.Collector for a set of Windows MetricCollectors.
-type Prometheus struct {
-	maxScrapeDuration time.Duration
-	logger            *slog.Logger
-	metricCollectors  *MetricCollectors
-
-	// Base metrics returned by Prometheus
-	scrapeDurationDesc          *prometheus.Desc
-	collectorScrapeDurationDesc *prometheus.Desc
-	collectorScrapeSuccessDesc  *prometheus.Desc
-	collectorScrapeTimeoutDesc  *prometheus.Desc
-}
-
 type collectorStatus struct {
 	name       string
 	statusCode collectorStatusCode
@@ -60,64 +42,26 @@ const (
 	failed
 )
 
-// NewPrometheusCollector returns a new Prometheus where the set of MetricCollectors must
-// return metrics within the given timeout.
-func (c *MetricCollectors) NewPrometheusCollector(timeout time.Duration, logger *slog.Logger) *Prometheus {
-	return &Prometheus{
-		maxScrapeDuration: timeout,
-		metricCollectors:  c,
-		logger:            logger,
-		scrapeDurationDesc: prometheus.NewDesc(
-			prometheus.BuildFQName(types.Namespace, "exporter", "scrape_duration_seconds"),
-			"windows_exporter: Total scrape duration.",
-			nil,
-			nil,
-		),
-		collectorScrapeDurationDesc: prometheus.NewDesc(
-			prometheus.BuildFQName(types.Namespace, "exporter", "collector_duration_seconds"),
-			"windows_exporter: Duration of a collection.",
-			[]string{"collector"},
-			nil,
-		),
-		collectorScrapeSuccessDesc: prometheus.NewDesc(
-			prometheus.BuildFQName(types.Namespace, "exporter", "collector_success"),
-			"windows_exporter: Whether the collector was successful.",
-			[]string{"collector"},
-			nil,
-		),
-		collectorScrapeTimeoutDesc: prometheus.NewDesc(
-			prometheus.BuildFQName(types.Namespace, "exporter", "collector_timeout"),
-			"windows_exporter: Whether the collector timed out.",
-			[]string{"collector"},
-			nil,
-		),
-	}
-}
-
-func (p *Prometheus) Describe(_ chan<- *prometheus.Desc) {}
-
-// Collect sends the collected metrics from each of the MetricCollectors to
-// prometheus.
-func (p *Prometheus) Collect(ch chan<- prometheus.Metric) {
+func (c *Collection) collectAll(ch chan<- prometheus.Metric, logger *slog.Logger, maxScrapeDuration time.Duration) {
 	collectorStartTime := time.Now()
 
 	// WaitGroup to wait for all collectors to finish
 	wg := sync.WaitGroup{}
-	wg.Add(len(p.metricCollectors.Collectors))
+	wg.Add(len(c.collectors))
 
 	// Using a channel to collect the status of each collector
 	// A channel is safe to use concurrently while a map is not
-	collectorStatusCh := make(chan collectorStatus, len(p.metricCollectors.Collectors))
+	collectorStatusCh := make(chan collectorStatus, len(c.collectors))
 
 	// Execute all collectors concurrently
 	// timeout handling is done in the execute function
-	for name, metricsCollector := range p.metricCollectors.Collectors {
+	for name, metricsCollector := range c.collectors {
 		go func(name string, metricsCollector Collector) {
 			defer wg.Done()
 
 			collectorStatusCh <- collectorStatus{
 				name:       name,
-				statusCode: p.execute(name, metricsCollector, ch),
+				statusCode: c.collectCollector(ch, logger, name, metricsCollector, maxScrapeDuration),
 			}
 		}(name, metricsCollector)
 	}
@@ -139,14 +83,14 @@ func (p *Prometheus) Collect(ch chan<- prometheus.Metric) {
 		}
 
 		ch <- prometheus.MustNewConstMetric(
-			p.collectorScrapeSuccessDesc,
+			c.collectorScrapeSuccessDesc,
 			prometheus.GaugeValue,
 			successValue,
 			status.name,
 		)
 
 		ch <- prometheus.MustNewConstMetric(
-			p.collectorScrapeTimeoutDesc,
+			c.collectorScrapeTimeoutDesc,
 			prometheus.GaugeValue,
 			timeoutValue,
 			status.name,
@@ -154,13 +98,13 @@ func (p *Prometheus) Collect(ch chan<- prometheus.Metric) {
 	}
 
 	ch <- prometheus.MustNewConstMetric(
-		p.scrapeDurationDesc,
+		c.scrapeDurationDesc,
 		prometheus.GaugeValue,
 		time.Since(collectorStartTime).Seconds(),
 	)
 }
 
-func (p *Prometheus) execute(name string, c Collector, ch chan<- prometheus.Metric) collectorStatusCode {
+func (c *Collection) collectCollector(ch chan<- prometheus.Metric, logger *slog.Logger, name string, collector Collector, maxScrapeDuration time.Duration) collectorStatusCode {
 	var (
 		err        error
 		numMetrics int
@@ -173,10 +117,10 @@ func (p *Prometheus) execute(name string, c Collector, ch chan<- prometheus.Metr
 	bufCh := make(chan prometheus.Metric, 1000)
 	errCh := make(chan error, 1)
 
-	ctx, cancel := context.WithTimeout(context.Background(), p.maxScrapeDuration)
+	ctx, cancel := context.WithTimeout(context.Background(), maxScrapeDuration)
 	defer cancel()
 
-	// Execute the collector
+	// execute the collector
 	go func() {
 		defer func() {
 			if r := recover(); r != nil {
@@ -188,7 +132,7 @@ func (p *Prometheus) execute(name string, c Collector, ch chan<- prometheus.Metr
 			close(bufCh)
 		}()
 
-		errCh <- c.Collect(bufCh)
+		errCh <- collector.Collect(bufCh)
 	}()
 
 	wg := sync.WaitGroup{}
@@ -232,7 +176,7 @@ func (p *Prometheus) execute(name string, c Collector, ch chan<- prometheus.Metr
 
 		duration = time.Since(t)
 		ch <- prometheus.MustNewConstMetric(
-			p.collectorScrapeDurationDesc,
+			c.collectorScrapeDurationDesc,
 			prometheus.GaugeValue,
 			duration.Seconds(),
 			name,
@@ -242,13 +186,13 @@ func (p *Prometheus) execute(name string, c Collector, ch chan<- prometheus.Metr
 
 		duration = time.Since(t)
 		ch <- prometheus.MustNewConstMetric(
-			p.collectorScrapeDurationDesc,
+			c.collectorScrapeDurationDesc,
 			prometheus.GaugeValue,
 			duration.Seconds(),
 			name,
 		)
 
-		p.logger.Warn(fmt.Sprintf("collector %s timeouted after %s, resulting in %d metrics", name, p.maxScrapeDuration, numMetrics))
+		logger.Warn(fmt.Sprintf("collector %s timeouted after %s, resulting in %d metrics", name, maxScrapeDuration, numMetrics))
 
 		go func() {
 			// Drain channel in case of premature return to not leak a goroutine.
@@ -261,12 +205,12 @@ func (p *Prometheus) execute(name string, c Collector, ch chan<- prometheus.Metr
 	}
 
 	if err != nil {
-		loggerFn := p.logger.Warn
+		loggerFn := logger.Warn
 		if errors.Is(err, types.ErrNoData) ||
 			errors.Is(err, perfdata.ErrNoData) ||
 			errors.Is(err, perfdata.ErrPerformanceCounterNotInitialized) ||
 			errors.Is(err, mi.MI_RESULT_INVALID_NAMESPACE) {
-			loggerFn = p.logger.Debug
+			loggerFn = logger.Debug
 		}
 
 		loggerFn(fmt.Sprintf("collector %s failed after %s, resulting in %d metrics", name, duration, numMetrics),
@@ -276,7 +220,7 @@ func (p *Prometheus) execute(name string, c Collector, ch chan<- prometheus.Metr
 		return failed
 	}
 
-	p.logger.Debug(fmt.Sprintf("collector %s succeeded after %s, resulting in %d metrics", name, duration, numMetrics))
+	logger.Debug(fmt.Sprintf("collector %s succeeded after %s, resulting in %d metrics", name, duration, numMetrics))
 
 	return success
 }

pkg/collector/collection.go

@@ -19,8 +19,10 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"maps"
 	"slices"
 	"sync"
+	gotime "time"
 
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/prometheus-community/windows_exporter/internal/collector/ad"
@@ -72,10 +74,12 @@ import (
 	"github.com/prometheus-community/windows_exporter/internal/collector/update"
 	"github.com/prometheus-community/windows_exporter/internal/collector/vmware"
 	"github.com/prometheus-community/windows_exporter/internal/mi"
+	"github.com/prometheus-community/windows_exporter/internal/types"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 // NewWithFlags To be called by the exporter for collector initialization before running kingpin.Parse.
-func NewWithFlags(app *kingpin.Application) *MetricCollectors {
+func NewWithFlags(app *kingpin.Application) *Collection {
 	collectors := map[string]Collector{}
 
 	for name, builder := range BuildersWithFlags {
@@ -88,7 +92,7 @@ func NewWithFlags(app *kingpin.Application) *MetricCollectors {
 // NewWithConfig To be called by the external libraries for collector initialization without running [kingpin.Parse].
 //
 //goland:noinspection GoUnusedExportedFunction
-func NewWithConfig(config Config) *MetricCollectors {
+func NewWithConfig(config Config) *Collection {
 	collectors := Map{}
 	collectors[ad.Name] = ad.New(&config.AD)
 	collectors[adcs.Name] = adcs.New(&config.ADCS)
@@ -143,23 +147,48 @@ func NewWithConfig(config Config) *MetricCollectors {
 }
 
 // New To be called by the external libraries for collector initialization.
-func New(collectors Map) *MetricCollectors {
-	return &MetricCollectors{
-		Collectors: collectors,
+func New(collectors Map) *Collection {
+	return &Collection{
+		collectors:    collectors,
+		concurrencyCh: make(chan struct{}, 1),
+		scrapeDurationDesc: prometheus.NewDesc(
+			prometheus.BuildFQName(types.Namespace, "exporter", "scrape_duration_seconds"),
+			"windows_exporter: Total scrape duration.",
+			nil,
+			nil,
+		),
+		collectorScrapeDurationDesc: prometheus.NewDesc(
+			prometheus.BuildFQName(types.Namespace, "exporter", "collector_duration_seconds"),
+			"windows_exporter: Duration of a collection.",
+			[]string{"collector"},
+			nil,
+		),
+		collectorScrapeSuccessDesc: prometheus.NewDesc(
+			prometheus.BuildFQName(types.Namespace, "exporter", "collector_success"),
+			"windows_exporter: Whether the collector was successful.",
+			[]string{"collector"},
+			nil,
+		),
+		collectorScrapeTimeoutDesc: prometheus.NewDesc(
+			prometheus.BuildFQName(types.Namespace, "exporter", "collector_timeout"),
+			"windows_exporter: Whether the collector timed out.",
+			[]string{"collector"},
+			nil,
+		),
 	}
 }
 
 // Enable removes all collectors that not enabledCollectors.
-func (c *MetricCollectors) Enable(enabledCollectors []string) error {
+func (c *Collection) Enable(enabledCollectors []string) error {
 	for _, name := range enabledCollectors {
-		if _, ok := c.Collectors[name]; !ok {
+		if _, ok := c.collectors[name]; !ok {
 			return fmt.Errorf("unknown collector %s", name)
 		}
 	}
 
-	for name := range c.Collectors {
+	for name := range c.collectors {
 		if !slices.Contains(enabledCollectors, name) {
-			delete(c.Collectors, name)
+			delete(c.collectors, name)
 		}
 	}
 
@@ -167,23 +196,25 @@ func (c *MetricCollectors) Enable(enabledCollectors []string) error {
 }
 
 // Build To be called by the exporter for collector initialization.
-func (c *MetricCollectors) Build(logger *slog.Logger) error {
+func (c *Collection) Build(logger *slog.Logger) error {
+	c.startTime = gotime.Now()
+
 	err := c.initMI()
 	if err != nil {
 		return fmt.Errorf("error from initialize MI: %w", err)
 	}
 
 	wg := sync.WaitGroup{}
-	wg.Add(len(c.Collectors))
+	wg.Add(len(c.collectors))
 
-	errCh := make(chan error, len(c.Collectors))
-	errs := make([]error, 0, len(c.Collectors))
+	errCh := make(chan error, len(c.collectors))
+	errs := make([]error, 0, len(c.collectors))
 
-	for _, collector := range c.Collectors {
+	for _, collector := range c.collectors {
 		go func() {
 			defer wg.Done()
 
-			if err = collector.Build(logger, c.MISession); err != nil {
+			if err = collector.Build(logger, c.miSession); err != nil {
 				errCh <- fmt.Errorf("error build collector %s: %w", collector.GetName(), err)
 			}
 		}()
@@ -201,21 +232,21 @@ func (c *MetricCollectors) Build(logger *slog.Logger) error {
 }
 
 // Close To be called by the exporter for collector cleanup.
-func (c *MetricCollectors) Close() error {
-	errs := make([]error, 0, len(c.Collectors))
+func (c *Collection) Close() error {
+	errs := make([]error, 0, len(c.collectors))
 
-	for _, collector := range c.Collectors {
+	for _, collector := range c.collectors {
 		if err := collector.Close(); err != nil {
 			errs = append(errs, fmt.Errorf("error from close collector %s: %w", collector.GetName(), err))
 		}
 	}
 
-	app, err := c.MISession.GetApplication()
+	app, err := c.miSession.GetApplication()
 	if err != nil && !errors.Is(err, mi.ErrNotInitialized) {
 		errs = append(errs, fmt.Errorf("error from get MI application: %w", err))
 	}
 
-	if err := c.MISession.Close(); err != nil && !errors.Is(err, mi.ErrNotInitialized) {
+	if err := c.miSession.Close(); err != nil && !errors.Is(err, mi.ErrNotInitialized) {
 		errs = append(errs, fmt.Errorf("error from close MI session: %w", err))
 	}
 
@@ -226,8 +257,8 @@ func (c *MetricCollectors) Close() error {
 	return errors.Join(errs...)
 }
 
-// Close To be called by the exporter for collector cleanup.
-func (c *MetricCollectors) initMI() error {
+// initMI To be called by the exporter for collector initialization.
+func (c *Collection) initMI() error {
 	app, err := mi.Application_Initialize()
 	if err != nil {
 		return fmt.Errorf("error from initialize MI application: %w", err)
@@ -242,10 +273,34 @@ func (c *MetricCollectors) initMI() error {
 		return fmt.Errorf("error from set locale: %w", err)
 	}
 
-	c.MISession, err = app.NewSession(destinationOptions)
+	c.miSession, err = app.NewSession(destinationOptions)
 	if err != nil {
 		return fmt.Errorf("error from create NewSession: %w", err)
 	}
 
 	return nil
 }
+
+// WithCollectors To be called by the exporter for collector initialization.
+func (c *Collection) WithCollectors(collectors []string) (*Collection, error) {
+	metricCollectors := &Collection{
+		miSession:                   c.miSession,
+		startTime:                   c.startTime,
+		concurrencyCh:               c.concurrencyCh,
+		scrapeDurationDesc:          c.scrapeDurationDesc,
+		collectorScrapeDurationDesc: c.collectorScrapeDurationDesc,
+		collectorScrapeSuccessDesc:  c.collectorScrapeSuccessDesc,
+		collectorScrapeTimeoutDesc:  c.collectorScrapeTimeoutDesc,
+		collectors:                  maps.Clone(c.collectors),
+	}
+
+	if err := metricCollectors.Enable(collectors); err != nil {
+		return nil, err
+	}
+
+	return metricCollectors, nil
+}
+
+func (c *Collection) GetStartTime() gotime.Time {
+	return c.startTime
+}

pkg/collector/handler.go

@@ -0,0 +1,62 @@
+// 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.
+
+//go:build windows
+
+package collector
+
+import (
+	"fmt"
+	"log/slog"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Interface guard.
+var _ prometheus.Collector = (*Handler)(nil)
+
+// Handler implements [prometheus.Collector] for a set of Windows Collection.
+type Handler struct {
+	maxScrapeDuration time.Duration
+	logger            *slog.Logger
+	collection        *Collection
+}
+
+// NewHandler returns a new Handler that implements a [prometheus.Collector] for the given metrics Collection.
+func (c *Collection) NewHandler(maxScrapeDuration time.Duration, logger *slog.Logger, collectors []string) (*Handler, error) {
+	collection := c
+
+	if len(collectors) != 0 {
+		var err error
+
+		collection, err = c.WithCollectors(collectors)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create handler with collectors: %w", err)
+		}
+	}
+
+	return &Handler{
+		maxScrapeDuration: maxScrapeDuration,
+		collection:        collection,
+		logger:            logger,
+	}, nil
+}
+
+func (p *Handler) Describe(_ chan<- *prometheus.Desc) {}
+
+// Collect sends the collected metrics from each of the Collection to
+// prometheus.
+func (p *Handler) Collect(ch chan<- prometheus.Metric) {
+	p.collection.collectAll(ch, p.logger, p.maxScrapeDuration)
+}

pkg/collector/types.go

@@ -17,6 +17,7 @@ package collector
 
 import (
 	"log/slog"
+	"time"
 
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/prometheus-community/windows_exporter/internal/mi"
@@ -25,10 +26,16 @@ import (
 
 const DefaultCollectors = "cpu,cs,memory,logical_disk,physical_disk,net,os,service,system"
 
-type MetricCollectors struct {
-	Collectors       Map
-	MISession        *mi.Session
-	PerfCounterQuery string
+type Collection struct {
+	collectors    Map
+	miSession     *mi.Session
+	startTime     time.Time
+	concurrencyCh chan struct{}
+
+	scrapeDurationDesc          *prometheus.Desc
+	collectorScrapeDurationDesc *prometheus.Desc
+	collectorScrapeSuccessDesc  *prometheus.Desc
+	collectorScrapeTimeoutDesc  *prometheus.Desc
 }
 
 type (