Add information about build to Prometheus publisher

.goreleaser.yml

@@ -25,6 +25,11 @@ builds:
       - goos: windows
         goarch: arm64
     main: ./cmd/smartmeter
+    ldflags:
+      - -s -w
+      - -X github.com/koesie10/smartmeter/version.Version={{.Version}}
+      - -X github.com/koesie10/smartmeter/version.Commit={{.Commit}}
+      - -X github.com/koesie10/smartmeter/version.BuildDate={{.Date}}
 checksum:
   name_template: 'checksums.txt'
 snapshot:

cmd/smartmeter/main.go

@@ -5,12 +5,6 @@ import (
 	"os"
 )
 
-var (
-	version = "dev"
-	commit  = "none"
-	date    = "unknown"
-)
-
 func main() {
 	if err := rootCmd.Execute(); err != nil {
 		fmt.Println(err)

cmd/smartmeter/root.go

@@ -8,6 +8,7 @@ import (
 	"github.com/jacobsa/go-serial/serial"
 	"github.com/koesie10/pflagenv"
 	"github.com/koesie10/smartmeter/serialinput"
+	"github.com/koesie10/smartmeter/version"
 	"github.com/spf13/cobra"
 	"go.uber.org/zap"
 )
@@ -44,9 +45,9 @@ var logger, _ = zap.NewDevelopment()
 var rootCmd = &cobra.Command{
 	Use: "smartmeter",
 	Version: fmt.Sprintf("%s (%s at %s)",
-		version,
-		commit,
-		date,
+		version.Version,
+		version.Commit,
+		version.BuildDate,
 	),
 	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
 		if err := pflagenv.Parse(&config); err != nil {

prometheus/publisher.go

@@ -2,13 +2,16 @@ package prometheus
 
 import (
 	"fmt"
-	"github.com/koesie10/smartmeter/smartmeter"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"log"
 	"net"
 	"net/http"
 	"strconv"
+
+	"github.com/koesie10/smartmeter/smartmeter"
+	"github.com/koesie10/smartmeter/version"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/collectors"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 var _ smartmeter.Publisher = (*publisher)(nil)
@@ -146,6 +149,25 @@ func NewPublisher(options PublisherOptions) (smartmeter.Publisher, error) {
 
 	registry.MustRegister(p.gasConsumed)
 
+	if !options.DisableGoCollector {
+		registry.MustRegister(collectors.NewGoCollector())
+		registry.MustRegister(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}))
+	}
+
+	buildInfo := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name:      "info",
+		Help:      "Information about the smartmeter build",
+		Namespace: "smartmeter",
+		ConstLabels: map[string]string{
+			"version":    version.Version,
+			"commit":     version.Commit,
+			"build_date": version.BuildDate,
+		},
+	})
+	buildInfo.Set(1)
+
+	registry.MustRegister(buildInfo)
+
 	mux := http.NewServeMux()
 	mux.Handle("/metrics", promhttp.HandlerFor(registry, promhttp.HandlerOpts{}))
 
@@ -170,6 +192,8 @@ func NewPublisher(options PublisherOptions) (smartmeter.Publisher, error) {
 
 type PublisherOptions struct {
 	Addr string `env:"PROMETHEUS_ADDR" flag:"addr" desc:"Prometheus HTTP server address, set empty to disable"`
+
+	DisableGoCollector bool `env:"DISABLE_GO_COLLECTOR" flag:"disable-go-collector" desc:"Disable Go collector"`
 }
 
 func (p *publisher) Publish(packet *smartmeter.P1Packet) error {

version/version.go

@@ -0,0 +1,33 @@
+package version
+
+import (
+	"fmt"
+	"time"
+)
+
+var (
+	// Version is the version of this build
+	Version string
+	// Commit is the commit of this build
+	Commit string
+	// BuildDate is the build date of this build in RFC3339 format
+	BuildDate string
+	// BuildTime is the build date of this build as a Go time.Time
+	BuildTime time.Time
+)
+
+func init() {
+	if Version == "" {
+		Version = "SNAPSHOT"
+	}
+
+	if BuildDate == "" {
+		BuildDate = time.Time{}.Format(time.RFC3339)
+	}
+
+	var err error
+	BuildTime, err = time.ParseInLocation(time.RFC3339, BuildDate, time.UTC)
+	if err != nil {
+		panic(fmt.Sprintf("failed to parse build time: %v", err))
+	}
+}