Merge pull request #241 from szook/protect-against-empty-result-set

protect against empty wmi query result sets

README.md

@@ -9,14 +9,16 @@ Prometheus exporter for Windows machines, using the WMI (Windows Management Inst
 
 Name     | Description | Enabled by default
 ---------|-------------|--------------------
-ad | [Win32_PerfRawData_DirectoryServices_DirectoryServices](https://msdn.microsoft.com/en-us/library/ms803980.aspx) Active Directory | 
+ad | [Win32_PerfRawData_DirectoryServices_DirectoryServices](https://msdn.microsoft.com/en-us/library/ms803980.aspx) Active Directory |
 cpu | [Win32_PerfRawData_PerfOS_Processor](https://msdn.microsoft.com/en-us/library/aa394317(v=vs.90).aspx) metrics (cpu usage) | ✓
 cs | [Win32_ComputerSystem](https://msdn.microsoft.com/en-us/library/aa394102) metrics (system properties, num cpus/total memory) | ✓
 dns | [Win32_PerfRawData_DNS_DNS](https://technet.microsoft.com/en-us/library/cc977686.aspx) metrics (DNS Server) |
+hyperv | Performance counters for Hyper-V hosts |
 iis | [Win32_PerfRawData_W3SVC_WebService](https://msdn.microsoft.com/en-us/library/aa394345) IIS metrics |
 logical_disk | [Win32_PerfRawData_PerfDisk_LogicalDisk](https://msdn.microsoft.com/en-us/windows/hardware/aa394307(v=vs.71)) metrics (disk I/O) | ✓
 net | [Win32_PerfRawData_Tcpip_NetworkInterface](https://technet.microsoft.com/en-us/security/aa394340(v=vs.80)) metrics (network interface I/O) | ✓
-msmq | [Win32_PerfRawData_MSMQ_MSMQQueue](http://wutils.com/wmi/root/cimv2/win32_perfrawdata_msmq_msmqqueue/) metrics (MSMQ/journal count) | 
+msmq | [Win32_PerfRawData_MSMQ_MSMQQueue](http://wutils.com/wmi/root/cimv2/win32_perfrawdata_msmq_msmqqueue/) metrics (MSMQ/journal count) |
+mssql | various [SQL Server Performance Objects](https://docs.microsoft.com/en-us/sql/relational-databases/performance-monitor/use-sql-server-objects#SQLServerPOs) metrics  |
 os | [Win32_OperatingSystem](https://msdn.microsoft.com/en-us/library/aa394239) metrics (memory, processes, users) | ✓
 process | [Win32_PerfRawData_PerfProc_Process](https://msdn.microsoft.com/en-us/library/aa394323(v=vs.85).aspx) metrics (per-process stats) |
 service | [Win32_Service](https://msdn.microsoft.com/en-us/library/aa394418(v=vs.85).aspx) metrics (service states) | ✓

collector/ad.go

@@ -3,6 +3,8 @@
 package collector
 
 import (
+	"errors"
+
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -612,10 +614,13 @@ type Win32_PerfRawData_DirectoryServices_DirectoryServices struct {
 
 func (c *ADCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_DirectoryServices_DirectoryServices
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
 
 	ch <- prometheus.MustNewConstMetric(
 		c.AddressBookOperationsTotal,

collector/cpu.go

@@ -117,7 +117,7 @@ type Win32_PerfRawData_Counters_ProcessorInformation struct {
 
 func (c *CPUCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_PerfOS_Processor
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/cs.go

@@ -4,6 +4,8 @@
 package collector
 
 import (
+	"errors"
+
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -56,9 +58,13 @@ type Win32_ComputerSystem struct {
 
 func (c *CSCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_ComputerSystem
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
 
 	ch <- prometheus.MustNewConstMetric(
 		c.LogicalProcessors,

collector/dns.go

@@ -4,6 +4,8 @@
 package collector
 
 import (
+	"errors"
+
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -233,10 +235,13 @@ type Win32_PerfRawData_DNS_DNS struct {
 
 func (c *DNSCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_DNS_DNS
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
 
 	ch <- prometheus.MustNewConstMetric(
 		c.ZoneTransferRequestsReceived,

collector/iis.go

@@ -7,6 +7,7 @@
 package collector
 
 import (
+	"errors"
 	"fmt"
 	"regexp"
 
@@ -20,7 +21,6 @@ import (
 
 func init() {
 	Factories["iis"] = NewIISCollector
-	iis_version = getIISVersion()
 }
 
 type simple_version struct {
@@ -60,8 +60,6 @@ var (
 	siteBlacklist = kingpin.Flag("collector.iis.site-blacklist", "Regexp of sites to blacklist. Site name must both match whitelist and not match blacklist to be included.").String()
 	appWhitelist  = kingpin.Flag("collector.iis.app-whitelist", "Regexp of apps to whitelist. App name must both match whitelist and not match blacklist to be included.").Default(".+").String()
 	appBlacklist  = kingpin.Flag("collector.iis.app-blacklist", "Regexp of apps to blacklist. App name must both match whitelist and not match blacklist to be included.").String()
-
-	iis_version = simple_version{}
 )
 
 type IISCollector struct {
@@ -188,13 +186,15 @@ type IISCollector struct {
 
 	appWhitelistPattern *regexp.Regexp
 	appBlacklistPattern *regexp.Regexp
+
+	iis_version simple_version
 }
 
 // NewIISCollector ...
 func NewIISCollector() (Collector, error) {
 	const subsystem = "iis"
 
-	return &IISCollector{
+	buildIIS := &IISCollector{
 		// Websites
 		// Gauges
 		CurrentAnonymousUsers: prometheus.NewDesc(
@@ -808,7 +808,11 @@ func NewIISCollector() (Collector, error) {
 
 		appWhitelistPattern: regexp.MustCompile(fmt.Sprintf("^(?:%s)$", *siteWhitelist)),
 		appBlacklistPattern: regexp.MustCompile(fmt.Sprintf("^(?:%s)$", *siteBlacklist)),
-	}, nil
+	}
+
+	buildIIS.iis_version = getIISVersion()
+
+	return buildIIS, nil
 }
 
 // Collect sends the metric values for each metric
@@ -995,7 +999,7 @@ var workerProcessNameExtractor = regexp.MustCompile(`^(\d+)_(.+)$`)
 
 func (c *IISCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_W3SVC_WebService
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
@@ -1248,7 +1252,7 @@ func (c *IISCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, e
 	}
 
 	var dst2 []Win32_PerfRawData_APPPOOLCountersProvider_APPPOOLWAS
-	q2 := wmi.CreateQuery(&dst2, "")
+	q2 := queryAll(&dst2)
 	if err := wmi.Query(q2, &dst2); err != nil {
 		return nil, err
 	}
@@ -1365,7 +1369,7 @@ func (c *IISCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, e
 	}
 
 	var dst_worker []Win32_PerfRawData_W3SVCW3WPCounterProvider_W3SVCW3WP
-	q = wmi.CreateQuery(&dst_worker, "")
+	q = queryAll(&dst_worker)
 	if err := wmi.Query(q, &dst_worker); err != nil {
 		return nil, err
 	}
@@ -1645,9 +1649,9 @@ func (c *IISCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, e
 		)
 	}
 
-	if iis_version.major >= 8 {
+	if c.iis_version.major >= 8 {
 		var dst_worker_iis8 []Win32_PerfRawData_W3SVCW3WPCounterProvider_W3SVCW3WP_IIS8
-		q = createQuery(&dst_worker_iis8, "Win32_PerfRawData_W3SVCW3WPCounterProvider_W3SVCW3WP", "")
+		q = queryAllForClass(&dst_worker_iis8, "Win32_PerfRawData_W3SVCW3WPCounterProvider_W3SVCW3WP")
 		if err := wmi.Query(q, &dst_worker_iis8); err != nil {
 			return nil, err
 		}
@@ -1730,11 +1734,15 @@ func (c *IISCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, e
 	}
 
 	var dst_cache []Win32_PerfRawData_W3SVC_WebServiceCache
-	q = wmi.CreateQuery(&dst_cache, "")
+	q = queryAll(&dst_cache)
 	if err := wmi.Query(q, &dst_cache); err != nil {
 		return nil, err
 	}
 
+	if len(dst_cache) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
+
 	ch <- prometheus.MustNewConstMetric(
 		c.ServiceCache_ActiveFlushedEntries,
 		prometheus.GaugeValue,

collector/logical_disk.go

@@ -161,7 +161,7 @@ type Win32_PerfRawData_PerfDisk_LogicalDisk struct {
 
 func (c *LogicalDiskCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_PerfDisk_LogicalDisk
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/msmq.go

@@ -3,7 +3,6 @@
 package collector
 
 import (
-	"bytes"
 	"strings"
 
 	"github.com/StackExchange/wmi"
@@ -34,10 +33,7 @@ type Win32_PerfRawData_MSMQ_MSMQQueueCollector struct {
 func NewMSMQCollector() (Collector, error) {
 	const subsystem = "msmq"
 
-	var wc bytes.Buffer
 	if *msmqWhereClause != "" {
-		wc.WriteString("WHERE ")
-		wc.WriteString(*msmqWhereClause)
 		log.Warn("No where-clause specified for msmq collector. This will generate a very large number of metrics!")
 	}
 
@@ -66,7 +62,7 @@ func NewMSMQCollector() (Collector, error) {
 			[]string{"name"},
 			nil,
 		),
-		queryWhereClause: wc.String(),
+		queryWhereClause: *msmqWhereClause,
 	}, nil
 }
 
@@ -91,7 +87,7 @@ type Win32_PerfRawData_MSMQ_MSMQQueue struct {
 
 func (c *Win32_PerfRawData_MSMQ_MSMQQueueCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_MSMQ_MSMQQueue
-	q := wmi.CreateQuery(&dst, c.queryWhereClause)
+	q := queryAllWhere(&dst, c.queryWhereClause)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/net.go

@@ -169,7 +169,7 @@ type Win32_PerfRawData_Tcpip_NetworkInterface struct {
 func (c *NetworkCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_Tcpip_NetworkInterface
 
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrexceptions.go

@@ -73,7 +73,7 @@ type Win32_PerfRawData_NETFramework_NETCLRExceptions struct {
 
 func (c *NETFramework_NETCLRExceptionsCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRExceptions
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrinterop.go

@@ -66,7 +66,7 @@ type Win32_PerfRawData_NETFramework_NETCLRInterop struct {
 
 func (c *NETFramework_NETCLRInteropCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRInterop
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrjit.go

@@ -75,7 +75,7 @@ type Win32_PerfRawData_NETFramework_NETCLRJit struct {
 
 func (c *NETFramework_NETCLRJitCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRJit
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrloading.go

@@ -119,7 +119,7 @@ type Win32_PerfRawData_NETFramework_NETCLRLoading struct {
 
 func (c *NETFramework_NETCLRLoadingCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRLoading
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrlocksandthreads.go

@@ -99,7 +99,7 @@ type Win32_PerfRawData_NETFramework_NETCLRLocksAndThreads struct {
 
 func (c *NETFramework_NETCLRLocksAndThreadsCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRLocksAndThreads
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrmemory.go

@@ -151,7 +151,7 @@ type Win32_PerfRawData_NETFramework_NETCLRMemory struct {
 
 func (c *NETFramework_NETCLRMemoryCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRMemory
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrremoting.go

@@ -89,7 +89,7 @@ type Win32_PerfRawData_NETFramework_NETCLRRemoting struct {
 
 func (c *NETFramework_NETCLRRemotingCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRRemoting
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/netframework_clrsecurity.go

@@ -74,7 +74,7 @@ type Win32_PerfRawData_NETFramework_NETCLRSecurity struct {
 
 func (c *NETFramework_NETCLRSecurityCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NETFramework_NETCLRSecurity
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/os.go

@@ -4,6 +4,7 @@
 package collector
 
 import (
+	"errors"
 	"time"
 
 	"github.com/StackExchange/wmi"
@@ -137,10 +138,15 @@ type Win32_OperatingSystem struct {
 
 func (c *OSCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_OperatingSystem
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
+
 	ch <- prometheus.MustNewConstMetric(
 		c.PhysicalMemoryFreeBytes,
 		prometheus.GaugeValue,

collector/process.go

@@ -3,7 +3,6 @@
 package collector
 
 import (
-	"bytes"
 	"strconv"
 	"strings"
 
@@ -47,11 +46,7 @@ type ProcessCollector struct {
 func NewProcessCollector() (Collector, error) {
 	const subsystem = "process"
 
-	var wc bytes.Buffer
-	if *processWhereClause != "" {
-		wc.WriteString("WHERE ")
-		wc.WriteString(*processWhereClause)
-	} else {
+	if *processWhereClause == "" {
 		log.Warn("No where-clause specified for process collector. This will generate a very large number of metrics!")
 	}
 
@@ -134,7 +129,7 @@ func NewProcessCollector() (Collector, error) {
 			[]string{"process", "process_id", "creating_process_id"},
 			nil,
 		),
-		queryWhereClause: wc.String(),
+		queryWhereClause: *processWhereClause,
 	}, nil
 }
 
@@ -182,13 +177,22 @@ type Win32_PerfRawData_PerfProc_Process struct {
 	WorkingSetPrivate       uint64
 }
 
+type WorkerProcess struct {
+	AppPoolName string
+	ProcessId   uint32
+}
+
 func (c *ProcessCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_PerfProc_Process
-	q := wmi.CreateQuery(&dst, c.queryWhereClause)
+	q := queryAllWhere(&dst, c.queryWhereClause)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
+	var dst_wp []WorkerProcess
+	q_wp := queryAll(&dst_wp)
+	wmi.QueryNamespace(q_wp, &dst_wp, "root\\WebAdministration")
+
 	for _, process := range dst {
 
 		if process.Name == "_Total" {
@@ -199,6 +203,13 @@ func (c *ProcessCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Des
 		pid := strconv.FormatUint(uint64(process.IDProcess), 10)
 		cpid := strconv.FormatUint(uint64(process.CreatingProcessID), 10)
 
+		for _, wp := range dst_wp {
+			if wp.ProcessId == process.IDProcess {
+				processName = strings.Join([]string{processName, wp.AppPoolName}, "_")
+				break
+			}
+		}
+
 		ch <- prometheus.MustNewConstMetric(
 			c.StartTime,
 			prometheus.GaugeValue,

collector/service.go

@@ -3,7 +3,6 @@
 package collector
 
 import (
-	"bytes"
 	"strings"
 
 	"github.com/StackExchange/wmi"
@@ -27,6 +26,7 @@ var (
 type serviceCollector struct {
 	State     *prometheus.Desc
 	StartMode *prometheus.Desc
+	Status    *prometheus.Desc
 
 	queryWhereClause string
 }
@@ -35,11 +35,7 @@ type serviceCollector struct {
 func NewserviceCollector() (Collector, error) {
 	const subsystem = "service"
 
-	var wc bytes.Buffer
-	if *serviceWhereClause != "" {
-		wc.WriteString("WHERE ")
-		wc.WriteString(*serviceWhereClause)
-	} else {
+	if *serviceWhereClause == "" {
 		log.Warn("No where-clause specified for service collector. This will generate a very large number of metrics!")
 	}
 
@@ -56,7 +52,13 @@ func NewserviceCollector() (Collector, error) {
 			[]string{"name", "start_mode"},
 			nil,
 		),
-		queryWhereClause: wc.String(),
+		Status: prometheus.NewDesc(
+			prometheus.BuildFQName(Namespace, subsystem, "status"),
+			"The status of the service (Status)",
+			[]string{"name", "status"},
+			nil,
+		),
+		queryWhereClause: *serviceWhereClause,
 	}, nil
 }
 
@@ -73,6 +75,7 @@ func (c *serviceCollector) Collect(ch chan<- prometheus.Metric) error {
 type Win32_Service struct {
 	Name      string
 	State     string
+	Status    string
 	StartMode string
 }
 
@@ -94,11 +97,25 @@ var (
 		"manual",
 		"disabled",
 	}
+	allStatuses = []string{
+		"ok",
+		"error",
+		"degraded",
+		"unknown",
+		"pred fail",
+		"starting",
+		"stopping",
+		"service",
+		"stressed",
+		"nonrecover",
+		"no contact",
+		"lost comm",
+	}
 )
 
 func (c *serviceCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_Service
-	q := wmi.CreateQuery(&dst, c.queryWhereClause)
+	q := queryAllWhere(&dst, c.queryWhereClause)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
@@ -131,6 +148,20 @@ func (c *serviceCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Des
 				startMode,
 			)
 		}
+
+		for _, status := range allStatuses {
+			isCurrentStatus := 0.0
+			if status == strings.ToLower(service.Status) {
+				isCurrentStatus = 1.0
+			}
+			ch <- prometheus.MustNewConstMetric(
+				c.Status,
+				prometheus.GaugeValue,
+				isCurrentStatus,
+				strings.ToLower(service.Name),
+				status,
+			)
+		}
 	}
 	return nil, nil
 }

collector/system.go

@@ -4,6 +4,7 @@
 package collector
 
 import (
+	"errors"
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -30,37 +31,37 @@ func NewSystemCollector() (Collector, error) {
 	return &SystemCollector{
 		ContextSwitchesTotal: prometheus.NewDesc(
 			prometheus.BuildFQName(Namespace, subsystem, "context_switches_total"),
-			"PerfOS_System.ContextSwitchesPersec",
+			"Total number of context switches (WMI source: PerfOS_System.ContextSwitchesPersec)",
 			nil,
 			nil,
 		),
 		ExceptionDispatchesTotal: prometheus.NewDesc(
 			prometheus.BuildFQName(Namespace, subsystem, "exception_dispatches_total"),
-			"PerfOS_System.ExceptionDispatchesPersec",
+			"Total number of exceptions dispatched (WMI source: PerfOS_System.ExceptionDispatchesPersec)",
 			nil,
 			nil,
 		),
 		ProcessorQueueLength: prometheus.NewDesc(
 			prometheus.BuildFQName(Namespace, subsystem, "processor_queue_length"),
-			"PerfOS_System.ProcessorQueueLength",
+			"Length of processor queue (WMI source: PerfOS_System.ProcessorQueueLength)",
 			nil,
 			nil,
 		),
 		SystemCallsTotal: prometheus.NewDesc(
 			prometheus.BuildFQName(Namespace, subsystem, "system_calls_total"),
-			"PerfOS_System.SystemCallsPersec",
+			"Total number of system calls (WMI source: PerfOS_System.SystemCallsPersec)",
 			nil,
 			nil,
 		),
 		SystemUpTime: prometheus.NewDesc(
 			prometheus.BuildFQName(Namespace, subsystem, "system_up_time"),
-			"SystemUpTime/Frequency_Object",
+			"System boot time (WMI source: PerfOS_System.SystemUpTime)",
 			nil,
 			nil,
 		),
 		Threads: prometheus.NewDesc(
 			prometheus.BuildFQName(Namespace, subsystem, "threads"),
-			"PerfOS_System.Threads",
+			"Current number of threads (WMI source: PerfOS_System.Threads)",
 			nil,
 			nil,
 		),
@@ -90,18 +91,22 @@ type Win32_PerfRawData_PerfOS_System struct {
 
 func (c *SystemCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_PerfOS_System
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
 
 	ch <- prometheus.MustNewConstMetric(
 		c.ContextSwitchesTotal,
-		prometheus.GaugeValue,
+		prometheus.CounterValue,
 		float64(dst[0].ContextSwitchesPersec),
 	)
 	ch <- prometheus.MustNewConstMetric(
 		c.ExceptionDispatchesTotal,
-		prometheus.GaugeValue,
+		prometheus.CounterValue,
 		float64(dst[0].ExceptionDispatchesPersec),
 	)
 	ch <- prometheus.MustNewConstMetric(
@@ -111,7 +116,7 @@ func (c *SystemCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc
 	)
 	ch <- prometheus.MustNewConstMetric(
 		c.SystemCallsTotal,
-		prometheus.GaugeValue,
+		prometheus.CounterValue,
 		float64(dst[0].SystemCallsPersec),
 	)
 	ch <- prometheus.MustNewConstMetric(

collector/tcp.go

@@ -5,6 +5,7 @@
 package collector
 
 import (
+	"errors"
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -114,10 +115,13 @@ type Win32_PerfRawData_Tcpip_TCPv4 struct {
 func (c *TCPCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_Tcpip_TCPv4
 
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
 
 	// Counters
 	ch <- prometheus.MustNewConstMetric(

collector/textfile.go

@@ -17,6 +17,7 @@ package collector
 
 import (
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -185,6 +186,30 @@ func (c *textFileCollector) exportMTimes(mtimes map[string]time.Time, ch chan<-
 	}
 }
 
+type carriageReturnFilteringReader struct {
+	r io.Reader
+}
+
+// Read returns data from the underlying io.Reader, but with \r filtered out
+func (cr carriageReturnFilteringReader) Read(p []byte) (int, error) {
+	buf := make([]byte, len(p))
+	n, err := cr.r.Read(buf)
+
+	if err != nil && err != io.EOF {
+		return n, err
+	}
+
+	pi := 0
+	for i := 0; i < n; i++ {
+		if buf[i] != '\r' {
+			p[pi] = buf[i]
+			pi++
+		}
+	}
+
+	return pi, err
+}
+
 // Update implements the Collector interface.
 func (c *textFileCollector) Collect(ch chan<- prometheus.Metric) error {
 	error := 0.0
@@ -203,6 +228,7 @@ fileLoop:
 			continue
 		}
 		path := filepath.Join(c.path, f.Name())
+		log.Debugf("Processing file %q", path)
 		file, err := os.Open(path)
 		if err != nil {
 			log.Errorf("Error opening %q: %v", path, err)
@@ -210,7 +236,7 @@ fileLoop:
 			continue
 		}
 		var parser expfmt.TextParser
-		parsedFamilies, err := parser.TextToMetricFamilies(file)
+		parsedFamilies, err := parser.TextToMetricFamilies(carriageReturnFilteringReader{r: file})
 		file.Close()
 		if err != nil {
 			log.Errorf("Error parsing %q: %v", path, err)

collector/textfile_test.go

@@ -0,0 +1,20 @@
+package collector
+
+import (
+	"testing"
+	"strings"
+	"io/ioutil"
+)
+
+func TestCRFilter(t *testing.T) {
+	sr := strings.NewReader("line 1\r\nline 2")
+	cr := carriageReturnFilteringReader{ r: sr }
+	b, err := ioutil.ReadAll(cr)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if string(b) != "line 1\nline 2" {
+		t.Errorf("Unexpected output %q", b)
+	}
+}

collector/vmware.go

@@ -2,6 +2,8 @@
 package collector
 
 import (
+	"errors"
+
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -197,10 +199,13 @@ type Win32_PerfRawData_vmGuestLib_VCPU struct {
 
 func (c *VmwareCollector) collectMem(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_vmGuestLib_VMem
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
 
 	ch <- prometheus.MustNewConstMetric(
 		c.MemActive,
@@ -283,10 +288,13 @@ func mbToBytes(mb uint64) float64 {
 
 func (c *VmwareCollector) collectCpu(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_vmGuestLib_VCPU
-	q := wmi.CreateQuery(&dst, "")
+	q := queryAll(&dst)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
 
 	ch <- prometheus.MustNewConstMetric(
 		c.CpuLimitMHz,

collector/wmi.go

@@ -3,9 +3,9 @@ package collector
 import (
 	"bytes"
 	"reflect"
-	"strings"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/log"
 )
 
 // ...
@@ -25,29 +25,57 @@ type Collector interface {
 	Collect(ch chan<- prometheus.Metric) (err error)
 }
 
-// This is adapted from StackExchange/wmi/wmi.go, and lets us change the class
-// name being queried for:
-// CreateQuery returns a WQL query string that queries all columns of src. where
-// is an optional string that is appended to the query, to be used with WHERE
-// clauses. In such a case, the "WHERE" string should appear at the beginning.
-func createQuery(src interface{}, class, where string) string {
-	var b bytes.Buffer
-	b.WriteString("SELECT ")
+func className(src interface{}) string {
 	s := reflect.Indirect(reflect.ValueOf(src))
 	t := s.Type()
 	if s.Kind() == reflect.Slice {
 		t = t.Elem()
 	}
-	if t.Kind() != reflect.Struct {
-		return ""
-	}
-	var fields []string
-	for i := 0; i < t.NumField(); i++ {
-		fields = append(fields, t.Field(i).Name)
-	}
-	b.WriteString(strings.Join(fields, ", "))
-	b.WriteString(" FROM ")
-	b.WriteString(class)
-	b.WriteString(" " + where)
+	return t.Name()
+}
+
+func queryAll(src interface{}) string {
+	var b bytes.Buffer
+	b.WriteString("SELECT * FROM ")
+	b.WriteString(className(src))
+
+	log.Debugf("Generated WMI query %s", b.String())
+	return b.String()
+}
+
+func queryAllForClass(src interface{}, class string) string {
+	var b bytes.Buffer
+	b.WriteString("SELECT * FROM ")
+	b.WriteString(class)
+
+	log.Debugf("Generated WMI query %s", b.String())
+	return b.String()
+}
+
+func queryAllWhere(src interface{}, where string) string {
+	var b bytes.Buffer
+	b.WriteString("SELECT * FROM ")
+	b.WriteString(className(src))
+
+	if where != "" {
+		b.WriteString(" WHERE ")
+		b.WriteString(where)
+	}
+
+	log.Debugf("Generated WMI query %s", b.String())
+	return b.String()
+}
+
+func queryAllForClassWhere(src interface{}, class string, where string) string {
+	var b bytes.Buffer
+	b.WriteString("SELECT * FROM ")
+	b.WriteString(class)
+
+	if where != "" {
+		b.WriteString(" WHERE ")
+		b.WriteString(where)
+	}
+
+	log.Debugf("Generated WMI query %s", b.String())
 	return b.String()
 }

collector/wmi_test.go

@@ -0,0 +1,115 @@
+package collector
+
+import (
+	"testing"
+)
+
+type fakeWmiClass struct {
+	Name         string
+	SomeProperty int
+}
+
+var (
+	mapQueryAll = func(src interface{}, class string, where string) string {
+		return queryAll(src)
+	}
+	mapQueryAllWhere = func(src interface{}, class string, where string) string {
+		return queryAllWhere(src, where)
+	}
+	mapQueryAllForClass = func(src interface{}, class string, where string) string {
+		return queryAllForClass(src, class)
+	}
+	mapQueryAllForClassWhere = func(src interface{}, class string, where string) string {
+		return queryAllForClassWhere(src, class, where)
+	}
+)
+
+type queryFunc func(src interface{}, class string, where string) string
+
+func TestCreateQuery(t *testing.T) {
+	cases := []struct {
+		desc      string
+		dst       interface{}
+		class     string
+		where     string
+		queryFunc queryFunc
+		expected  string
+	}{
+		{
+			desc:      "queryAll on single instance",
+			dst:       fakeWmiClass{},
+			queryFunc: mapQueryAll,
+			expected:  "SELECT * FROM fakeWmiClass",
+		},
+		{
+			desc:      "queryAll on slice",
+			dst:       []fakeWmiClass{},
+			queryFunc: mapQueryAll,
+			expected:  "SELECT * FROM fakeWmiClass",
+		},
+		{
+			desc:      "queryAllWhere on single instance",
+			dst:       fakeWmiClass{},
+			where:     "foo = bar",
+			queryFunc: mapQueryAllWhere,
+			expected:  "SELECT * FROM fakeWmiClass WHERE foo = bar",
+		},
+		{
+			desc:      "queryAllWhere on slice",
+			dst:       []fakeWmiClass{},
+			where:     "foo = bar",
+			queryFunc: mapQueryAllWhere,
+			expected:  "SELECT * FROM fakeWmiClass WHERE foo = bar",
+		},
+		{
+			desc:      "queryAllWhere on single instance with empty where",
+			dst:       fakeWmiClass{},
+			queryFunc: mapQueryAllWhere,
+			expected:  "SELECT * FROM fakeWmiClass",
+		},
+		{
+			desc:      "queryAllForClass on single instance",
+			dst:       fakeWmiClass{},
+			class:     "someClass",
+			queryFunc: mapQueryAllForClass,
+			expected:  "SELECT * FROM someClass",
+		},
+		{
+			desc:      "queryAllForClass on slice",
+			dst:       []fakeWmiClass{},
+			class:     "someClass",
+			queryFunc: mapQueryAllForClass,
+			expected:  "SELECT * FROM someClass",
+		},
+		{
+			desc:      "queryAllForClassWhere on single instance",
+			dst:       fakeWmiClass{},
+			class:     "someClass",
+			where:     "foo = bar",
+			queryFunc: mapQueryAllForClassWhere,
+			expected:  "SELECT * FROM someClass WHERE foo = bar",
+		},
+		{
+			desc:      "queryAllForClassWhere on slice",
+			dst:       []fakeWmiClass{},
+			class:     "someClass",
+			where:     "foo = bar",
+			queryFunc: mapQueryAllForClassWhere,
+			expected:  "SELECT * FROM someClass WHERE foo = bar",
+		},
+		{
+			desc:      "queryAllForClassWhere on single instance with empty where",
+			dst:       fakeWmiClass{},
+			class:     "someClass",
+			queryFunc: mapQueryAllForClassWhere,
+			expected:  "SELECT * FROM someClass",
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.desc, func(t *testing.T) {
+			if q := c.queryFunc(c.dst, c.class, c.where); q != c.expected {
+				t.Errorf("Case %q failed: Expected %q, got %q", c.desc, c.expected, q)
+			}
+		})
+	}
+}

exporter.go

@@ -44,6 +44,16 @@ var (
 		[]string{"collector"},
 		nil,
 	)
+
+	// This can be removed when client_golang exposes this on Windows
+	// (See https://github.com/prometheus/client_golang/issues/376)
+	startTime     = float64(time.Now().Unix())
+	startTimeDesc = prometheus.NewDesc(
+		"process_start_time_seconds",
+		"Start time of the process since unix epoch in seconds.",
+		nil,
+		nil,
+	)
 )
 
 // Describe sends all the descriptors of the collectors included to
@@ -65,6 +75,12 @@ func (coll WmiCollector) Collect(ch chan<- prometheus.Metric) {
 			wg.Done()
 		}(name, c)
 	}
+
+	ch <- prometheus.MustNewConstMetric(
+		startTimeDesc,
+		prometheus.CounterValue,
+		startTime,
+	)
 	wg.Wait()
 }
 
@@ -153,6 +169,7 @@ func initWbem() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	wmi.DefaultClient.AllowMissingFields = true
 	wmi.DefaultClient.SWbemServicesClient = s
 }
 
@@ -168,7 +185,7 @@ func main() {
 		).Default("/metrics").String()
 		enabledCollectors = kingpin.Flag(
 			"collectors.enabled",
-			"Comma-separated list of collectors to use. Use '[default]' as a placeholder for all the collectors enabled by default.").
+			"Comma-separated list of collectors to use. Use '[defaults]' as a placeholder for all the collectors enabled by default.").
 			Default(filterAvailableCollectors(defaultCollectors)).String()
 		printCollectors = kingpin.Flag(
 			"collectors.print",

tools/collector-generator/collector.template

@@ -46,7 +46,7 @@ type {{ .Class }} struct {
 }
 func (c *{{ .CollectorName }}Collector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
     var dst []{{ .Class }}
-    q := wmi.CreateQuery(&dst, "")
+    q := queryAll(&dst)
     if err := wmi.Query(q, &dst); err != nil {
         return nil, err
     }