Merge pull request #693 from SuperQ/https

Add HTTPS configuration

README.md

@@ -77,6 +77,7 @@ Flag     | Description | Default value
 `--collectors.enabled` | Comma-separated list of collectors to use. Use `[defaults]` as a placeholder for all the collectors enabled by default." | `[defaults]`
 `--collectors.print` | If true, print available collectors and exit. | 
 `--scrape.timeout-margin` | Seconds to subtract from the timeout allowed by the client. Tune to allow for overhead or high loads. | `0.5`
+`--web.config` | A [web config][web_config] for setting up TLS and Auth | None
 
 ## Installation
 The latest release can be downloaded from the [releases page](https://github.com/prometheus-community/windows_exporter/releases).
@@ -169,3 +170,5 @@ CLI flags enjoy a higher priority over values specified in the configuration fil
 ## License
 
 Under [MIT](LICENSE)
+
+[web_config]: https://github.com/prometheus/exporter-toolkit/blob/master/docs/web-configuration.md

collector/ad.go

@@ -6,8 +6,8 @@ import (
 	"errors"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/collector.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 
 	"github.com/leoluk/perflib_exporter/perflib"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"golang.org/x/sys/windows/registry"
 )
 

collector/container.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/Microsoft/hcsshim"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/cs.go

@@ -6,8 +6,8 @@ import (
 	"errors"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/dfsr.go

@@ -3,8 +3,8 @@
 package collector
 
 import (
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/dns.go

@@ -6,8 +6,8 @@ import (
 	"errors"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/exchange.go

@@ -7,8 +7,8 @@ import (
 	"os"
 	"strings"
 
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/fsrmquota.go

@@ -2,8 +2,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/hyperv.go

@@ -6,8 +6,8 @@ import (
 	"strings"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/iis.go

@@ -10,8 +10,8 @@ import (
 	"golang.org/x/sys/windows/registry"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/logical_disk.go

@@ -6,8 +6,8 @@ import (
 	"fmt"
 	"regexp"
 
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/logon.go

@@ -6,8 +6,8 @@ import (
 	"errors"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/memory.go

@@ -6,8 +6,8 @@
 package collector
 
 import (
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/msmq.go

@@ -6,8 +6,8 @@ import (
 	"strings"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/mssql.go

@@ -10,8 +10,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"golang.org/x/sys/windows/registry"
 	"gopkg.in/alecthomas/kingpin.v2"
 )

collector/net.go

@@ -6,8 +6,8 @@ import (
 	"fmt"
 	"regexp"
 
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/netframework_clrexceptions.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/netframework_clrinterop.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/netframework_clrjit.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/netframework_clrloading.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/netframework_clrlocksandthreads.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/netframework_clrmemory.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/netframework_clrremoting.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/netframework_clrsecurity.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/os.go

@@ -7,8 +7,8 @@ import (
 	"time"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/perflib.go

@@ -7,7 +7,7 @@ import (
 
 	perflibCollector "github.com/leoluk/perflib_exporter/collector"
 	"github.com/leoluk/perflib_exporter/perflib"
-	"github.com/prometheus/common/log"
+	"github.com/prometheus-community/windows_exporter/log"
 )
 
 var nametable = perflib.QueryNameTable("Counter 009") // Reads the names in English TODO: validate that the English names are always present

collector/process.go

@@ -9,8 +9,8 @@ import (
 	"strings"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/remote_fx.go

@@ -5,8 +5,8 @@ package collector
 import (
 	"strings"
 
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/service.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/smtp.go

@@ -4,8 +4,8 @@ package collector
 
 import (
 	"fmt"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 	"regexp"
 )

collector/system.go

@@ -3,8 +3,8 @@
 package collector
 
 import (
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/tcp.go

@@ -3,8 +3,8 @@
 package collector
 
 import (
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/terminal_services.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 const ConnectionBrokerFeatureID uint32 = 133

collector/textfile.go

@@ -26,10 +26,10 @@ import (
 	"time"
 
 	"github.com/dimchansky/utfbom"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
 	dto "github.com/prometheus/client_model/go"
 	"github.com/prometheus/common/expfmt"
-	"github.com/prometheus/common/log"
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 

collector/thermalzone.go

@@ -2,8 +2,8 @@ package collector
 
 import (
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/time.go

@@ -5,8 +5,8 @@ package collector
 import (
 	"errors"
 
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/vmware.go

@@ -6,8 +6,8 @@ import (
 	"errors"
 
 	"github.com/StackExchange/wmi"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/common/log"
 )
 
 func init() {

collector/wmi.go

@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"reflect"
 
-	"github.com/prometheus/common/log"
+	"github.com/prometheus-community/windows_exporter/log"
 )
 
 func className(src interface{}) string {

config/config.go

@@ -17,7 +17,7 @@ import (
 	"io/ioutil"
 	"os"
 
-	"github.com/prometheus/common/log"
+	"github.com/prometheus-community/windows_exporter/log"
 	"gopkg.in/alecthomas/kingpin.v2"
 	"gopkg.in/yaml.v2"
 )

exporter.go

@@ -19,10 +19,11 @@ import (
 	"github.com/StackExchange/wmi"
 	"github.com/prometheus-community/windows_exporter/collector"
 	"github.com/prometheus-community/windows_exporter/config"
+	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"github.com/prometheus/common/log"
 	"github.com/prometheus/common/version"
+	"github.com/prometheus/exporter-toolkit/https"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -258,6 +259,10 @@ func main() {
 			"config.file",
 			"YAML configuration file to use. Values set in this file will be overriden by CLI flags.",
 		).String()
+		httpsConfig = kingpin.Flag(
+			"web.config",
+			"[EXPERIMENTAL] Path to config yaml file that can enable TLS or authentication.",
+		).Default("").String()
 		listenAddress = kingpin.Flag(
 			"telemetry.addr",
 			"host:port for exporter.",
@@ -398,7 +403,10 @@ func main() {
 
 	go func() {
 		log.Infoln("Starting server on", *listenAddress)
-		log.Fatalf("cannot start windows_exporter: %s", http.ListenAndServe(*listenAddress, nil))
+		server := &http.Server{Addr: *listenAddress}
+		if err := https.Listen(server, *httpsConfig, log.NewToolkitAdapter()); err != nil {
+			log.Fatalf("cannot start windows_exporter: %s", err)
+		}
 	}()
 
 	for {

go.mod

@@ -7,14 +7,17 @@ require (
 	github.com/Microsoft/hcsshim v0.8.6
 	github.com/StackExchange/wmi v0.0.0-20180725035823-b12b22c5341f
 	github.com/dimchansky/utfbom v1.1.0
+	github.com/go-kit/kit v0.10.0
 	github.com/go-ole/go-ole v1.2.1 // indirect
 	github.com/google/go-cmp v0.5.1 // indirect
 	github.com/leoluk/perflib_exporter v0.1.0
 	github.com/prometheus/client_golang v1.8.0
 	github.com/prometheus/client_model v0.2.0
-	github.com/prometheus/common v0.14.0
+	github.com/prometheus/common v0.15.0
+	github.com/prometheus/exporter-toolkit v0.4.0
+	github.com/sirupsen/logrus v1.6.0
 	golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
-	gopkg.in/yaml.v2 v2.3.0
+	gopkg.in/yaml.v2 v2.4.0
 )

go.sum

@@ -72,13 +72,16 @@ github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMo
 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
 github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-kit/kit v0.9.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
+github.com/go-kit/kit v0.10.0 h1:dXFJfIHVvUcpSgDOV+Ne6t7jXri8Tfv2uOLHUZ2XNuo=
 github.com/go-kit/kit v0.10.0/go.mod h1:xUsJbQ/Fp4kEt7AFgCuvyX4a71u8h9jB8tj/ORgOZ7o=
 github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9GBnD5lWE=
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
+github.com/go-logfmt/logfmt v0.5.0 h1:TrB8swr/68K7m9CcGut2g3UOihhbcbiMAYiuTXdEih4=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-ole/go-ole v1.2.1 h1:2lOsA72HgjxAuMlKpFiCbHTvu44PIVkZ5hqm3RSdI/E=
 github.com/go-ole/go-ole v1.2.1/go.mod h1:7FAglXiTm7HKlQRDeOQ6ZNUHidzCWXuZWq/1dTyBNF8=
 github.com/go-sql-driver/mysql v1.4.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
+github.com/go-stack/stack v1.8.0 h1:5SgMzNM5HxrEjV0ww2lTmX6E2Izsfxas4+YHWRs3Lsk=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/gogo/googleapis v1.1.0/go.mod h1:gf4bu3Q80BeJ6H1S1vYPm8/ELATdvryBaNFGgqEef3s=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
@@ -146,6 +149,7 @@ github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANyt
 github.com/influxdata/influxdb1-client v0.0.0-20191209144304-8bf82d3c094d/go.mod h1:qj24IKcXYK6Iy9ceXlo3Tc+vtHo9lIhSX5JddghvEPo=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
 github.com/jonboulle/clockwork v0.1.0/go.mod h1:Ii8DK3G1RaLaWxj9trq07+26W01tbo22gdxWY5EU2bo=
+github.com/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.7/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
@@ -190,6 +194,7 @@ github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJ
 github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
 github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
+github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f h1:KUppIJq7/+SVif2QVs3tOP0zanoHgBEVAwHxUSIzRqU=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/nats-io/jwt v0.3.0/go.mod h1:fRYCDE99xlTsqUzISS1Bi75UBJ6ljOJQOAAu5VglpSg=
 github.com/nats-io/jwt v0.3.2/go.mod h1:/euKqTS1ZD+zzjYrY7pseZrTtWQSjujC7xjPc8wL6eU=
@@ -221,6 +226,7 @@ github.com/pierrec/lz4 v1.0.2-0.20190131084431-473cd7ce01a1/go.mod h1:3/3N9NVKO0
 github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/profile v1.2.1/go.mod h1:hJw3o1OdXxsrSjjVksARp5W95eeEaEfptyVZyv6JUPA=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -251,6 +257,10 @@ github.com/prometheus/common v0.7.0/go.mod h1:DjGbpBbp5NYNiECxcL/VnbXCCaQpKd3tt2
 github.com/prometheus/common v0.10.0/go.mod h1:Tlit/dnDKsSWFlCLTWaA1cyBgKHSMdTB80sz/V91rCo=
 github.com/prometheus/common v0.14.0 h1:RHRyE8UocrbjU+6UvRzwi6HjiDfxrrBU91TtbKzkGp4=
 github.com/prometheus/common v0.14.0/go.mod h1:U+gB1OBLb1lF3O42bTCL+FK18tX9Oar16Clt/msog/s=
+github.com/prometheus/common v0.15.0 h1:4fgOnadei3EZvgRwxJ7RMpG1k1pOZth5Pc13tyspaKM=
+github.com/prometheus/common v0.15.0/go.mod h1:U+gB1OBLb1lF3O42bTCL+FK18tX9Oar16Clt/msog/s=
+github.com/prometheus/exporter-toolkit v0.4.0 h1:O7Bw+ZKEMzW7vD10IuVF70b8EE4JIG7BvHFj9UKz49g=
+github.com/prometheus/exporter-toolkit v0.4.0/go.mod h1:OCkM4805mmisBhLmVFw858QYi3v0wKdY6/UxrT0pZVg=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/prometheus/procfs v0.0.0-20181204211112-1dc9a6cbc91a h1:9a8MnZMP0X2nLJdBg+pBmGgkJlSaKC2KaQmTCk1XDtE=
 github.com/prometheus/procfs v0.0.0-20181204211112-1dc9a6cbc91a/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
@@ -314,6 +324,8 @@ golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.0.0-20201208171446-5f87f3452ae9 h1:sYNJzB4J8toYPQTM6pAkcmBRgw9SnQKP9oXCHfgy604=
+golang.org/x/crypto v0.0.0-20201208171446-5f87f3452ae9/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
@@ -338,6 +350,7 @@ golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR
 golang.org/x/net v0.0.0-20190613194153-d28f0bde5980/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200625001655-4c5254603344 h1:vGXIOMxbNfDTk/aXCmfdLgkrSV+Z2tcbze+pEc3v5W4=
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -366,6 +379,7 @@ golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b h1:ag/x1USPSsqHud38I9BAC88qd
 golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190826190057-c7b8b68b1456/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191220142924-d4481acd189f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -373,7 +387,9 @@ golang.org/x/sys v0.0.0-20200615200032-f1bc736245b1/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211 h1:9UQO31fZ+0aKQOFldThf7BKPMJTiBfWycGh/u3UoO88=
 golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
@@ -442,6 +458,8 @@ gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.5/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

log/eventlog_formatter.go

@@ -0,0 +1,91 @@
+// Copyright 2015 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.
+//
+// Implementation forked from github.com/prometheus/common
+//
+// +build windows
+
+package log
+
+import (
+	"fmt"
+	"os"
+
+	"golang.org/x/sys/windows/svc/eventlog"
+
+	"github.com/sirupsen/logrus"
+)
+
+func init() {
+	setEventlogFormatter = func(l logger, name string, debugAsInfo bool) error {
+		if name == "" {
+			return fmt.Errorf("missing name parameter")
+		}
+
+		fmter, err := newEventlogger(name, debugAsInfo, l.entry.Logger.Formatter)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error creating eventlog formatter: %v\n", err)
+			l.Errorf("can't connect logger to eventlog: %v", err)
+			return err
+		}
+		l.entry.Logger.Formatter = fmter
+		return nil
+	}
+}
+
+type eventlogger struct {
+	log         *eventlog.Log
+	debugAsInfo bool
+	wrap        logrus.Formatter
+}
+
+func newEventlogger(name string, debugAsInfo bool, fmter logrus.Formatter) (*eventlogger, error) {
+	logHandle, err := eventlog.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return &eventlogger{log: logHandle, debugAsInfo: debugAsInfo, wrap: fmter}, nil
+}
+
+func (s *eventlogger) Format(e *logrus.Entry) ([]byte, error) {
+	data, err := s.wrap.Format(e)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "eventlogger: can't format entry: %v\n", err)
+		return data, err
+	}
+
+	switch e.Level {
+	case logrus.PanicLevel:
+		fallthrough
+	case logrus.FatalLevel:
+		fallthrough
+	case logrus.ErrorLevel:
+		err = s.log.Error(102, e.Message)
+	case logrus.WarnLevel:
+		err = s.log.Warning(101, e.Message)
+	case logrus.InfoLevel:
+		err = s.log.Info(100, e.Message)
+	case logrus.DebugLevel:
+		if s.debugAsInfo {
+			err = s.log.Info(100, e.Message)
+		}
+	default:
+		err = s.log.Info(100, e.Message)
+	}
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "eventlogger: can't send log to eventlog: %v\n", err)
+	}
+
+	return data, err
+}

log/gokit_adapter.go

@@ -0,0 +1,46 @@
+package log
+
+import (
+	"github.com/go-kit/kit/log/level"
+)
+
+// Returns an adapter implementing the go-kit/kit/log.Logger interface on our
+// logrus logger
+func NewToolkitAdapter() *logAdapter {
+	return &logAdapter{}
+}
+
+type logAdapter struct{}
+
+func (*logAdapter) Log(keyvals ...interface{}) error {
+	var lvl level.Value
+	var msg string
+	for i := 0; i < len(keyvals); i += 2 {
+		switch keyvals[i] {
+		case "level":
+			tlvl, ok := keyvals[i+1].(level.Value)
+			if !ok {
+				Warnf("Could not cast level of type %T", keyvals[i+1])
+			} else {
+				lvl = tlvl
+			}
+		case "msg":
+			msg = keyvals[i+1].(string)
+		}
+	}
+
+	switch lvl {
+	case level.ErrorValue():
+		Errorln(msg)
+	case level.WarnValue():
+		Warnln(msg)
+	case level.InfoValue():
+		Infoln(msg)
+	case level.DebugValue():
+		Debugln(msg)
+	default:
+		Warnf("Unmatched log level: '%v' for message %q", lvl, msg)
+	}
+
+	return nil
+}

log/log.go

@@ -0,0 +1,367 @@
+// Copyright 2015 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.
+
+// Package log implements logging via logrus.
+// Implementation forked from github.com/prometheus/common
+
+package log
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/url"
+	"os"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+// setSyslogFormatter is nil if the target architecture does not support syslog.
+var setSyslogFormatter func(logger, string, string) error
+
+// setEventlogFormatter is nil if the target OS does not support Eventlog (i.e., is not Windows).
+var setEventlogFormatter func(logger, string, bool) error
+
+func setJSONFormatter() {
+	origLogger.Formatter = &logrus.JSONFormatter{}
+}
+
+type loggerSettings struct {
+	level  string
+	format string
+}
+
+func (s *loggerSettings) apply(ctx *kingpin.ParseContext) error {
+	err := baseLogger.SetLevel(s.level)
+	if err != nil {
+		return err
+	}
+	err = baseLogger.SetFormat(s.format)
+	return err
+}
+
+// AddFlags adds the flags used by this package to the Kingpin application.
+// To use the default Kingpin application, call AddFlags(kingpin.CommandLine)
+func AddFlags(a *kingpin.Application) {
+	s := loggerSettings{}
+	a.Flag("log.level", "Only log messages with the given severity or above. Valid levels: [debug, info, warn, error, fatal]").
+		Default(origLogger.Level.String()).
+		StringVar(&s.level)
+	defaultFormat := url.URL{Scheme: "logger", Opaque: "stderr"}
+	a.Flag("log.format", `Set the log target and format. Example: "logger:syslog?appname=bob&local=7" or "logger:stdout?json=true"`).
+		Default(defaultFormat.String()).
+		StringVar(&s.format)
+	a.Action(s.apply)
+}
+
+// Logger is the interface for loggers used in the Prometheus components.
+type Logger interface {
+	Debug(...interface{})
+	Debugln(...interface{})
+	Debugf(string, ...interface{})
+
+	Info(...interface{})
+	Infoln(...interface{})
+	Infof(string, ...interface{})
+
+	Warn(...interface{})
+	Warnln(...interface{})
+	Warnf(string, ...interface{})
+
+	Error(...interface{})
+	Errorln(...interface{})
+	Errorf(string, ...interface{})
+
+	Fatal(...interface{})
+	Fatalln(...interface{})
+	Fatalf(string, ...interface{})
+
+	With(key string, value interface{}) Logger
+
+	SetFormat(string) error
+	SetLevel(string) error
+}
+
+type logger struct {
+	entry *logrus.Entry
+}
+
+func (l logger) With(key string, value interface{}) Logger {
+	return logger{l.entry.WithField(key, value)}
+}
+
+// Debug logs a message at level Debug on the standard logger.
+func (l logger) Debug(args ...interface{}) {
+	l.sourced().Debug(args...)
+}
+
+// Debug logs a message at level Debug on the standard logger.
+func (l logger) Debugln(args ...interface{}) {
+	l.sourced().Debugln(args...)
+}
+
+// Debugf logs a message at level Debug on the standard logger.
+func (l logger) Debugf(format string, args ...interface{}) {
+	l.sourced().Debugf(format, args...)
+}
+
+// Info logs a message at level Info on the standard logger.
+func (l logger) Info(args ...interface{}) {
+	l.sourced().Info(args...)
+}
+
+// Info logs a message at level Info on the standard logger.
+func (l logger) Infoln(args ...interface{}) {
+	l.sourced().Infoln(args...)
+}
+
+// Infof logs a message at level Info on the standard logger.
+func (l logger) Infof(format string, args ...interface{}) {
+	l.sourced().Infof(format, args...)
+}
+
+// Warn logs a message at level Warn on the standard logger.
+func (l logger) Warn(args ...interface{}) {
+	l.sourced().Warn(args...)
+}
+
+// Warn logs a message at level Warn on the standard logger.
+func (l logger) Warnln(args ...interface{}) {
+	l.sourced().Warnln(args...)
+}
+
+// Warnf logs a message at level Warn on the standard logger.
+func (l logger) Warnf(format string, args ...interface{}) {
+	l.sourced().Warnf(format, args...)
+}
+
+// Error logs a message at level Error on the standard logger.
+func (l logger) Error(args ...interface{}) {
+	l.sourced().Error(args...)
+}
+
+// Error logs a message at level Error on the standard logger.
+func (l logger) Errorln(args ...interface{}) {
+	l.sourced().Errorln(args...)
+}
+
+// Errorf logs a message at level Error on the standard logger.
+func (l logger) Errorf(format string, args ...interface{}) {
+	l.sourced().Errorf(format, args...)
+}
+
+// Fatal logs a message at level Fatal on the standard logger.
+func (l logger) Fatal(args ...interface{}) {
+	l.sourced().Fatal(args...)
+}
+
+// Fatal logs a message at level Fatal on the standard logger.
+func (l logger) Fatalln(args ...interface{}) {
+	l.sourced().Fatalln(args...)
+}
+
+// Fatalf logs a message at level Fatal on the standard logger.
+func (l logger) Fatalf(format string, args ...interface{}) {
+	l.sourced().Fatalf(format, args...)
+}
+
+func (l logger) SetLevel(level string) error {
+	lvl, err := logrus.ParseLevel(level)
+	if err != nil {
+		return err
+	}
+
+	l.entry.Logger.Level = lvl
+	return nil
+}
+
+func (l logger) SetFormat(format string) error {
+	u, err := url.Parse(format)
+	if err != nil {
+		return err
+	}
+	if u.Scheme != "logger" {
+		return fmt.Errorf("invalid scheme %s", u.Scheme)
+	}
+	jsonq := u.Query().Get("json")
+	if jsonq == "true" {
+		setJSONFormatter()
+	}
+
+	switch u.Opaque {
+	case "syslog":
+		if setSyslogFormatter == nil {
+			return fmt.Errorf("system does not support syslog")
+		}
+		appname := u.Query().Get("appname")
+		facility := u.Query().Get("local")
+		return setSyslogFormatter(l, appname, facility)
+	case "eventlog":
+		if setEventlogFormatter == nil {
+			return fmt.Errorf("system does not support eventlog")
+		}
+		name := u.Query().Get("name")
+		debugAsInfo := false
+		debugAsInfoRaw := u.Query().Get("debugAsInfo")
+		if parsedDebugAsInfo, err := strconv.ParseBool(debugAsInfoRaw); err == nil {
+			debugAsInfo = parsedDebugAsInfo
+		}
+		return setEventlogFormatter(l, name, debugAsInfo)
+	case "stdout":
+		l.entry.Logger.Out = os.Stdout
+	case "stderr":
+		l.entry.Logger.Out = os.Stderr
+	default:
+		return fmt.Errorf("unsupported logger %q", u.Opaque)
+	}
+	return nil
+}
+
+// sourced adds a source field to the logger that contains
+// the file name and line where the logging happened.
+func (l logger) sourced() *logrus.Entry {
+	_, file, line, ok := runtime.Caller(2)
+	if !ok {
+		file = "<???>"
+		line = 1
+	} else {
+		slash := strings.LastIndex(file, "/")
+		file = file[slash+1:]
+	}
+	return l.entry.WithField("source", fmt.Sprintf("%s:%d", file, line))
+}
+
+var origLogger = logrus.New()
+var baseLogger = logger{entry: logrus.NewEntry(origLogger)}
+
+// Base returns the default Logger logging to
+func Base() Logger {
+	return baseLogger
+}
+
+// NewLogger returns a new Logger logging to out.
+func NewLogger(w io.Writer) Logger {
+	l := logrus.New()
+	l.Out = w
+	return logger{entry: logrus.NewEntry(l)}
+}
+
+// NewNopLogger returns a logger that discards all log messages.
+func NewNopLogger() Logger {
+	l := logrus.New()
+	l.Out = ioutil.Discard
+	return logger{entry: logrus.NewEntry(l)}
+}
+
+// With adds a field to the logger.
+func With(key string, value interface{}) Logger {
+	return baseLogger.With(key, value)
+}
+
+// Debug logs a message at level Debug on the standard logger.
+func Debug(args ...interface{}) {
+	baseLogger.sourced().Debug(args...)
+}
+
+// Debugln logs a message at level Debug on the standard logger.
+func Debugln(args ...interface{}) {
+	baseLogger.sourced().Debugln(args...)
+}
+
+// Debugf logs a message at level Debug on the standard logger.
+func Debugf(format string, args ...interface{}) {
+	baseLogger.sourced().Debugf(format, args...)
+}
+
+// Info logs a message at level Info on the standard logger.
+func Info(args ...interface{}) {
+	baseLogger.sourced().Info(args...)
+}
+
+// Infoln logs a message at level Info on the standard logger.
+func Infoln(args ...interface{}) {
+	baseLogger.sourced().Infoln(args...)
+}
+
+// Infof logs a message at level Info on the standard logger.
+func Infof(format string, args ...interface{}) {
+	baseLogger.sourced().Infof(format, args...)
+}
+
+// Warn logs a message at level Warn on the standard logger.
+func Warn(args ...interface{}) {
+	baseLogger.sourced().Warn(args...)
+}
+
+// Warnln logs a message at level Warn on the standard logger.
+func Warnln(args ...interface{}) {
+	baseLogger.sourced().Warnln(args...)
+}
+
+// Warnf logs a message at level Warn on the standard logger.
+func Warnf(format string, args ...interface{}) {
+	baseLogger.sourced().Warnf(format, args...)
+}
+
+// Error logs a message at level Error on the standard logger.
+func Error(args ...interface{}) {
+	baseLogger.sourced().Error(args...)
+}
+
+// Errorln logs a message at level Error on the standard logger.
+func Errorln(args ...interface{}) {
+	baseLogger.sourced().Errorln(args...)
+}
+
+// Errorf logs a message at level Error on the standard logger.
+func Errorf(format string, args ...interface{}) {
+	baseLogger.sourced().Errorf(format, args...)
+}
+
+// Fatal logs a message at level Fatal on the standard logger.
+func Fatal(args ...interface{}) {
+	baseLogger.sourced().Fatal(args...)
+}
+
+// Fatalln logs a message at level Fatal on the standard logger.
+func Fatalln(args ...interface{}) {
+	baseLogger.sourced().Fatalln(args...)
+}
+
+// Fatalf logs a message at level Fatal on the standard logger.
+func Fatalf(format string, args ...interface{}) {
+	baseLogger.sourced().Fatalf(format, args...)
+}
+
+// AddHook adds hook to Prometheus' original logger.
+func AddHook(hook logrus.Hook) {
+	origLogger.Hooks.Add(hook)
+}
+
+type errorLogWriter struct{}
+
+func (errorLogWriter) Write(b []byte) (int, error) {
+	baseLogger.sourced().Error(string(b))
+	return len(b), nil
+}
+
+// NewErrorLogger returns a log.Logger that is meant to be used
+// in the ErrorLog field of an http.Server to log HTTP server errors.
+func NewErrorLogger() *log.Logger {
+	return log.New(&errorLogWriter{}, "", 0)
+}