Merge pull request #209 from martinlindhe/wmi-query-wildcard

* Refactor wmi query generator to use wildcard selector

collector/ad.go

@@ -612,7 +612,7 @@ 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
 	}

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

@@ -56,7 +56,8 @@ 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
 	}
 

collector/dns.go

@@ -233,7 +233,7 @@ 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
 	}

collector/hyperv.go

@@ -95,7 +95,7 @@ type HyperVCollector struct {
 
 	// Win32_PerfRawData_Counters_HyperVVirtualStorageDevice
 	VMStorageErrorCount      *prometheus.Desc
-	VMStorageQueueLength  	 *prometheus.Desc
+	VMStorageQueueLength     *prometheus.Desc
 	VMStorageReadBytes       *prometheus.Desc
 	VMStorageReadOperations  *prometheus.Desc
 	VMStorageWriteBytes      *prometheus.Desc
@@ -657,7 +657,8 @@ type Win32_PerfRawData_VmmsVirtualMachineStats_HyperVVirtualMachineHealthSummary
 
 func (c *HyperVCollector) collectVmHealth(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_VmmsVirtualMachineStats_HyperVVirtualMachineHealthSummary
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -689,7 +690,8 @@ type Win32_PerfRawData_VidPerfProvider_HyperVVMVidPartition struct {
 
 func (c *HyperVCollector) collectVmVid(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_VidPerfProvider_HyperVVMVidPartition
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -752,7 +754,8 @@ type Win32_PerfRawData_HvStats_HyperVHypervisorRootPartition struct {
 
 func (c *HyperVCollector) collectVmHv(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_HvStats_HyperVHypervisorRootPartition
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -889,7 +892,8 @@ type Win32_PerfRawData_HvStats_HyperVHypervisor struct {
 
 func (c *HyperVCollector) collectVmProcessor(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_HvStats_HyperVHypervisor
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -923,7 +927,8 @@ type Win32_PerfRawData_HvStats_HyperVHypervisorRootVirtualProcessor struct {
 
 func (c *HyperVCollector) collectHostCpuUsage(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_HvStats_HyperVHypervisorRootVirtualProcessor
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -983,7 +988,8 @@ type Win32_PerfRawData_HvStats_HyperVHypervisorVirtualProcessor struct {
 
 func (c *HyperVCollector) collectVmCpuUsage(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_HvStats_HyperVHypervisorVirtualProcessor
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -1060,7 +1066,8 @@ type Win32_PerfRawData_NvspSwitchStats_HyperVVirtualSwitch struct {
 
 func (c *HyperVCollector) collectVmSwitch(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NvspSwitchStats_HyperVVirtualSwitch
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -1218,7 +1225,8 @@ type Win32_PerfRawData_EthernetPerfProvider_HyperVLegacyNetworkAdapter struct {
 
 func (c *HyperVCollector) collectVmEthernet(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_EthernetPerfProvider_HyperVLegacyNetworkAdapter
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -1287,7 +1295,8 @@ type Win32_PerfRawData_Counters_HyperVVirtualStorageDevice struct {
 
 func (c *HyperVCollector) collectVmStorage(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_Counters_HyperVVirtualStorageDevice
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 
@@ -1355,7 +1364,8 @@ type Win32_PerfRawData_NvspNicStats_HyperVVirtualNetworkAdapter struct {
 
 func (c *HyperVCollector) collectVmNetwork(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_PerfRawData_NvspNicStats_HyperVVirtualNetworkAdapter
-	if err := wmi.Query(wmi.CreateQuery(&dst, ""), &dst); err != nil {
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}
 

collector/iis.go

@@ -995,7 +995,7 @@ 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 +1248,7 @@ 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 +1365,7 @@ 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
 	}
@@ -1647,7 +1647,7 @@ func (c *IISCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, e
 
 	if 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
 		}
@@ -1730,7 +1730,7 @@ 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
 	}

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

@@ -137,7 +137,8 @@ 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
 	}
 

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
 }
 
@@ -184,7 +179,7 @@ type Win32_PerfRawData_PerfProc_Process struct {
 
 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
 	}

collector/service.go

@@ -3,7 +3,6 @@
 package collector
 
 import (
-	"bytes"
 	"strings"
 
 	"github.com/StackExchange/wmi"
@@ -36,11 +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!")
 	}
 
@@ -63,7 +58,7 @@ func NewserviceCollector() (Collector, error) {
 			[]string{"name", "status"},
 			nil,
 		),
-		queryWhereClause: wc.String(),
+		queryWhereClause: *serviceWhereClause,
 	}, nil
 }
 
@@ -120,7 +115,7 @@ var (
 
 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
 	}

collector/system.go

@@ -90,7 +90,8 @@ 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
 	}
 

collector/tcp.go

@@ -114,7 +114,7 @@ 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
 	}

collector/vmware.go

@@ -197,7 +197,7 @@ 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
 	}
@@ -283,7 +283,7 @@ 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
 	}

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

@@ -47,7 +47,7 @@ var (
 
 	// 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())
+	startTime     = float64(time.Now().Unix())
 	startTimeDesc = prometheus.NewDesc(
 		"process_start_time_seconds",
 		"Start time of the process since unix epoch in seconds.",
@@ -169,6 +169,7 @@ func initWbem() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	wmi.DefaultClient.AllowMissingFields = true
 	wmi.DefaultClient.SWbemServicesClient = s
 }
 

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
     }