Added flag to filter services (like the one for processes). Added example for said flag in README.md (#109)

Implement IIS worker process and server cache classes

Makefile

@@ -1,2 +1,5 @@
 fmt:
 	gofmt -l -w -s .
+
+build:
+	promu build -v .

README.md

@@ -52,13 +52,22 @@ See [open issues](https://github.com/martinlindhe/wmi_exporter/issues)
 ## Usage
 
     go get -u github.com/kardianos/govendor
+    go get -u github.com/prometheus/promu
     go get -u github.com/martinlindhe/wmi_exporter
     cd $env:GOPATH/src/github.com/martinlindhe/wmi_exporter
-    govendor build +local
+    promu build -v .
     .\wmi_exporter.exe
 
 The prometheus metrics will be exposed on [localhost:9182](http://localhost:9182)
 
+## Examples
+
+Please note: The quotes in the parameter names are required because of how Powershell parses command line arguments.
+
+### Enable only service collector and specify a custom query
+
+    .\wmi_exporter.exe "-collectors.enabled" "service" "-collector.service.services-where" "Name='wmi_exporter'"
+
 
 ## License
 

collector/ad.go

@@ -3,9 +3,10 @@
 package collector
 
 import (
+	"log"
+
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {
@@ -454,7 +455,7 @@ func NewADCollector() (Collector, error) {
 // to the provided prometheus Metric channel.
 func (c *ADCollector) Collect(ch chan<- prometheus.Metric) error {
 	if desc, err := c.collect(ch); err != nil {
-		log.Errorf("[ERROR] failed collecting ad metrics:", desc, err)
+		log.Println("[ERROR] failed collecting ad metrics:", desc, err)
 		return err
 	}
 	return nil

collector/process.go

@@ -5,12 +5,12 @@ package collector
 import (
 	"bytes"
 	"flag"
+	"log"
 	"strconv"
 	"strings"
 
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {
@@ -49,7 +49,7 @@ func NewProcessCollector() (Collector, error) {
 		wc.WriteString("WHERE ")
 		wc.WriteString(*processWhereClause)
 	} else {
-		log.Warn("No where-clause specified for process collector. This will generate a very large number of metrics!")
+		log.Println("warning: No where-clause specified for process collector. This will generate a very large number of metrics!")
 	}
 
 	return &ProcessCollector{
@@ -139,7 +139,7 @@ func NewProcessCollector() (Collector, error) {
 // to the provided prometheus Metric channel.
 func (c *ProcessCollector) Collect(ch chan<- prometheus.Metric) error {
 	if desc, err := c.collect(ch); err != nil {
-		log.Errorln("[ERROR] failed collecting process metrics:", desc, err)
+		log.Println("[ERROR] failed collecting process metrics:", desc, err)
 		return err
 	}
 	return nil

collector/service.go

@@ -3,6 +3,8 @@
 package collector
 
 import (
+	"bytes"
+	"flag"
 	"log"
 	"strings"
 
@@ -14,15 +16,30 @@ func init() {
 	Factories["service"] = NewserviceCollector
 }
 
+var (
+	serviceWhereClause = flag.String("collector.service.services-where", "", "WQL 'where' clause to use in WMI metrics query. Limits the response to the services you specify and reduces the size of the response.")
+)
+
 // A serviceCollector is a Prometheus collector for WMI Win32_Service metrics
 type serviceCollector struct {
 	State     *prometheus.Desc
 	StartMode *prometheus.Desc
+
+	queryWhereClause string
 }
 
 // NewserviceCollector ...
 func NewserviceCollector() (Collector, error) {
 	const subsystem = "service"
+
+	var wc bytes.Buffer
+	if *serviceWhereClause != "" {
+		wc.WriteString("WHERE ")
+		wc.WriteString(*serviceWhereClause)
+	} else {
+		log.Println("warning: No where-clause specified for process collector. This will generate a very large number of metrics!")
+	}
+
 	return &serviceCollector{
 		State: prometheus.NewDesc(
 			prometheus.BuildFQName(Namespace, subsystem, "state"),
@@ -36,6 +53,7 @@ func NewserviceCollector() (Collector, error) {
 			[]string{"name", "start_mode"},
 			nil,
 		),
+		queryWhereClause: wc.String(),
 	}, nil
 }
 
@@ -77,7 +95,7 @@ var (
 
 func (c *serviceCollector) collect(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
 	var dst []Win32_Service
-	q := wmi.CreateQuery(&dst, "")
+	q := wmi.CreateQuery(&dst, c.queryWhereClause)
 	if err := wmi.Query(q, &dst); err != nil {
 		return nil, err
 	}

collector/wmi.go

@@ -1,6 +1,12 @@
 package collector
 
-import "github.com/prometheus/client_golang/prometheus"
+import (
+	"bytes"
+	"reflect"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
 
 // ...
 const (
@@ -18,3 +24,30 @@ type Collector interface {
 	// Get new metrics and expose them via prometheus registry.
 	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 ")
+	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 b.String()
+}

exporter.go

@@ -157,6 +157,13 @@ func initWbem() {
 	wmi.DefaultClient.SWbemServicesClient = s
 }
 
+func usage() {
+	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
+	flag.PrintDefaults()
+	fmt.Fprintf(os.Stderr, "\nNote: If executing from Powershell, the flags need to quoted. For example:\n%s\n",
+		"\twmi_exporter \"-collectors.enabled\" iis")
+}
+
 func main() {
 	var (
 		showVersion       = flag.Bool("version", false, "Print version information.")
@@ -165,6 +172,7 @@ func main() {
 		enabledCollectors = flag.String("collectors.enabled", filterAvailableCollectors(defaultCollectors), "Comma-separated list of collectors to use. Use '[default]' as a placeholder for all the collectors enabled by default")
 		printCollectors   = flag.Bool("collectors.print", false, "If true, print available collectors and exit.")
 	)
+	flag.Usage = usage
 	flag.Parse()
 
 	if *showVersion {

installer/wmi_exporter.wxs

@@ -36,7 +36,7 @@
         <File Id="wmi_exporter.exe" Name="wmi_exporter.exe" Source="Work\wmi_exporter.exe" KeyPath="yes">
           <fw:FirewallException Id="MetricsEndpoint" Name="WMI Exporter (HTTP [LISTEN_PORT])" Description="WMI Exporter HTTP endpoint" Port="[LISTEN_PORT]" Protocol="tcp" Scope="any" IgnoreFailure="yes" />
         </File>
-        <ServiceInstall Id="InstallExporterService" Name="wmi_exporter" ErrorControl="normal" Start="auto" Type="ownProcess" Arguments="-log.format logger:eventlog?name=wmi_exporter [CollectorsFlag] [ListenFlag] [MetricsPathFlag]" />
+        <ServiceInstall Id="InstallExporterService" Name="wmi_exporter" DisplayName="WMI exporter" Description="Exports Prometheus metrics from WMI queries" ErrorControl="normal" Start="auto" Type="ownProcess" Arguments="-log.format logger:eventlog?name=wmi_exporter [CollectorsFlag] [ListenFlag] [MetricsPathFlag]" />
         <ServiceControl Id="ServiceStateControl" Name="wmi_exporter" Remove="uninstall" Start="install" Stop="both" />
       </Component>
     </ComponentGroup>