Add AppInfo metric & automatic build time app info population (#178)

.github/workflows/ci.yml

@@ -39,10 +39,18 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v3
 
-      - name: Prepare
-        id: prep
-        run: |
-          echo ::set-output name=version::${GITHUB_REF##*/}
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ghcr.io/${{ github.repository }}
+          flavor: |
+            latest=true
+            prefix=v
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
@@ -73,5 +81,9 @@ jobs:
           file: ./Dockerfile
           platforms: linux/amd64,linux/arm64
           push: true
-          tags: |
-            ghcr.io/${{ github.repository_owner }}/exportarr:${{ steps.prep.outputs.version }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            VERSION=${{ steps.meta.outputs.version }}
+            BUILDTIME=${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.created'] }}
+            REVISION=${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.revision'] }}

.goreleaser.yml

@@ -7,6 +7,10 @@ archives:
 builds:
   - main: "./cmd/exportarr"
     binary: "exportarr"
+
+    ldflags:
+      - -s -w -X main.version={{.Version}} -X main.revision={{.Commit}} -X main.buildTime={{.CommitTimestamp}}
+
     goarch:
       - "386"
       - "amd64"

Dockerfile

@@ -2,6 +2,11 @@ FROM golang:1.20.5-alpine as builder
 ARG TARGETOS
 ARG TARGETARCH
 ARG TARGETVARIANT=""
+
+ARG VERSION="development"
+ARG BUILDTIME=""
+ARG REVISION=""
+
 ENV GO111MODULE=on \
     CGO_ENABLED=0 \
     GOOS=${TARGETOS} \
@@ -11,7 +16,7 @@ RUN apk add --no-cache ca-certificates tini-static \
     && update-ca-certificates
 WORKDIR /build
 COPY . .
-RUN go build -a -tags netgo -ldflags '-w -extldflags "-static"' -o exportarr /build/cmd/exportarr/.
+RUN go build -a -tags netgo -ldflags "-w -extldflags '-static' -X main.version=${VERSION} -X main.buildTime=${BUILDTIME} -X main.revision=${REVISION}" -o exportarr /build/cmd/exportarr/.
 
 FROM gcr.io/distroless/static:nonroot
 ENV PORT="9707"

cmd/exportarr/main.go

@@ -2,6 +2,18 @@ package main
 
 import "github.com/onedr0p/exportarr/internal/commands"
 
+var (
+	appName   = "exportarr"
+	version   = "development"
+	buildTime = ""
+	revision  = ""
+)
+
 func main() {
-	commands.Execute()
+	commands.Execute(commands.AppInfo{
+		Name:      appName,
+		Version:   version,
+		BuildTime: buildTime,
+		Revision:  revision,
+	})
 }

internal/commands/arr.go

@@ -49,7 +49,7 @@ var radarrCmd = &cobra.Command{
 		c.ApiVersion = "v3"
 		UsageOnError(cmd, c.Validate())
 
-		serveHttp(func(r *prometheus.Registry) {
+		serveHttp(func(r prometheus.Registerer) {
 			r.MustRegister(
 				collector.NewRadarrCollector(c),
 				collector.NewQueueCollector(c),
@@ -76,7 +76,7 @@ var sonarrCmd = &cobra.Command{
 		c.ApiVersion = "v3"
 		UsageOnError(cmd, c.Validate())
 
-		serveHttp(func(r *prometheus.Registry) {
+		serveHttp(func(r prometheus.Registerer) {
 			r.MustRegister(
 				collector.NewSonarrCollector(c),
 				collector.NewQueueCollector(c),
@@ -102,7 +102,7 @@ var lidarrCmd = &cobra.Command{
 		c.ApiVersion = "v1"
 		UsageOnError(cmd, c.Validate())
 
-		serveHttp(func(r *prometheus.Registry) {
+		serveHttp(func(r prometheus.Registerer) {
 			r.MustRegister(
 				collector.NewLidarrCollector(c),
 				collector.NewQueueCollector(c),
@@ -129,7 +129,7 @@ var readarrCmd = &cobra.Command{
 		c.ApiVersion = "v1"
 		UsageOnError(cmd, c.Validate())
 
-		serveHttp(func(r *prometheus.Registry) {
+		serveHttp(func(r prometheus.Registerer) {
 			r.MustRegister(
 				collector.NewReadarrCollector(c),
 				collector.NewQueueCollector(c),
@@ -161,7 +161,7 @@ var prowlarrCmd = &cobra.Command{
 		UsageOnError(cmd, c.Validate())
 		UsageOnError(cmd, c.Prowlarr.Validate())
 
-		serveHttp(func(r *prometheus.Registry) {
+		serveHttp(func(r prometheus.Registerer) {
 			r.MustRegister(
 				collector.NewProwlarrCollector(c),
 				collector.NewHistoryCollector(c),

internal/commands/root.go

@@ -22,8 +22,8 @@ import (
 var GRACEFUL_TIMEOUT = 5 * time.Second
 
 var (
-	conf = &config.Config{}
-
+	conf    = &config.Config{}
+	appInfo = &AppInfo{}
 	rootCmd = &cobra.Command{
 		Use:   "exportarr",
 		Short: "exportarr is a AIO Prometheus exporter for *arr applications",
@@ -36,7 +36,15 @@ More information available at the Github Repo (https://github.com/onedr0p/export
 	}
 )
 
-func Execute() error {
+type AppInfo struct {
+	Name      string
+	Version   string
+	BuildTime string
+	Revision  string
+}
+
+func Execute(a AppInfo) error {
+	appInfo = &a
 	return rootCmd.Execute()
 }
 
@@ -83,7 +91,13 @@ func initLogger() {
 	}
 	atom.SetLevel(lvl)
 
-	zap.S().Debug("Logger initialized")
+	zap.S().Infow(
+		fmt.Sprintf("Starting %s", appInfo.Name),
+		"app_name", appInfo.Name,
+		"version", appInfo.Version,
+		"buildTime", appInfo.BuildTime,
+		"revision", appInfo.Revision,
+	)
 }
 
 func finalizeLogger() {
@@ -91,7 +105,7 @@ func finalizeLogger() {
 	zap.S().Sync()
 }
 
-type registerFunc func(registry *prometheus.Registry)
+type registerFunc func(registry prometheus.Registerer)
 
 func serveHttp(fn registerFunc) {
 	var srv http.Server
@@ -116,6 +130,7 @@ func serveHttp(fn registerFunc) {
 	}()
 
 	registry := prometheus.NewRegistry()
+	registerAppInfoMetric(registry)
 	fn(registry)
 
 	mux := http.NewServeMux()
@@ -140,3 +155,20 @@ func serveHttp(fn registerFunc) {
 	}
 	<-idleConnsClosed
 }
+
+func registerAppInfoMetric(registry prometheus.Registerer) {
+	registry.MustRegister(prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: appInfo.Name,
+			Name:      "app_info",
+			Help:      "A metric with a constant '1' value labeled by app name, version, build time, and revision.",
+			ConstLabels: prometheus.Labels{
+				"app_name":   appInfo.Name,
+				"version":    appInfo.Version,
+				"build_time": appInfo.BuildTime,
+				"revision":   appInfo.Revision,
+			},
+		},
+		func() float64 { return 1 },
+	))
+}

internal/commands/sabnzbd.go

@@ -29,7 +29,7 @@ var sabnzbdCmd = &cobra.Command{
 		if err != nil {
 			return err
 		}
-		serveHttp(func(r *prometheus.Registry) {
+		serveHttp(func(r prometheus.Registerer) {
 			r.MustRegister(collector)
 		})
 		return nil