Use prometheus/common/version for versioning and exposing metric

Makefile

@@ -3,9 +3,16 @@ GOTOOLS=github.com/mitchellh/gox/...
 NAME=cloudmonitor_exporter
 
 VERSION=0.1.5
-BUILD_TIME=`date '+%F-%T%z'`
-
-LDFLAGS=-ldflags "-X main.version=${VERSION} -X main.buildtime=${BUILD_TIME}"
+COMMIT=$(shell git rev-parse HEAD)
+BRANCH=$(shell git rev-parse --abbrev-ref HEAD)
+BUILDER=$(shell whoami)@$(shell hostname)
+BUILD_DATE=$(shell date '+%F-%T%z')
+VERSION_PATH=github.com/ExpressenAB/cloudmonitor_exporter/vendor/github.com/prometheus/common/version
+LDFLAGS=-ldflags "-X ${VERSION_PATH}.Version=${VERSION} \
+                  -X ${VERSION_PATH}.Revision=${COMMIT} \
+                  -X ${VERSION_PATH}.Branch=${BRANCH} \
+                  -X ${VERSION_PATH}.BuildUser=${BUILDER} \
+                  -X ${VERSION_PATH}.BuildDate=${BUILD_DATE}"
 
 all: tools build
 

cloudmonitor_exporter.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"github.com/avct/user-agent-surfer"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/version"
 	"log"
 	"net"
 	"net/http"
@@ -18,11 +19,6 @@ import (
 	"time"
 )
 
-var (
-	version   string
-	buildtime string
-)
-
 var (
 	listenAddress     = flag.String("exporter.address", ":9143", "The address on which to expose the web interface and generated Prometheus metrics.")
 	namespace         = flag.String("exporter.namespace", "cloudmonitor", "The prometheus namespace.")
@@ -540,7 +536,7 @@ func main() {
 
 	flag.Parse()
 
-	log.Printf("Cloudmonitor-exporter v%s\n", version+"("+buildtime+")")
+	log.Printf("Cloudmonitor-exporter %s\n", version.Print("cloudmonitor_exporter"))
 	if *showVersion {
 		return
 	}
@@ -552,6 +548,7 @@ func main() {
 		log.Printf("logging to %s", *accesslog)
 	}
 
+	prometheus.MustRegister(version.NewCollector("cloudmonitor_exporter"))
 	prometheus.MustRegister(exporter)
 
 	http.Handle(*metricsEndpoint, prometheus.Handler())

vendor/vendor.json

@@ -56,6 +56,12 @@
 			"revision": "49fee292b27bfff7f354ee0f64e1bc4850462edf",
 			"revisionTime": "2017-02-20T10:38:46Z"
 		},
+		{
+			"checksumSHA1": "91KYK0SpvkaMJJA2+BcxbVnyRO0=",
+			"path": "github.com/prometheus/common/version",
+			"revision": "bc8b88226a1210b016e9993b1d75f858c9c8f778",
+			"revisionTime": "2017-08-30T19:05:55Z"
+		},
 		{
 			"checksumSHA1": "cD4xn1qxbkiuXqUExpdnDroCTrY=",
 			"path": "github.com/prometheus/procfs",
@@ -69,5 +75,5 @@
 			"revisionTime": "2017-02-16T22:32:56Z"
 		}
 	],
-	"rootPath": "cloudmonitor_exporter"
+	"rootPath": "github.com/ExpressenAB/cloudmonitor_exporter"
 }