add build info metric (operator-framework#67)

Co-authored-by: Joe Lanford <joe.lanford@gmail.com>

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/onsi/ginkgo v1.14.1
 	github.com/onsi/gomega v1.10.2
 	github.com/operator-framework/operator-lib v0.3.0
+	github.com/prometheus/client_golang v1.7.1
 	github.com/sirupsen/logrus v1.7.0
 	github.com/spf13/afero v1.2.2
 	github.com/spf13/cobra v1.1.1

internal/cmd/run/cmd.go

@@ -29,7 +29,9 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/healthz"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 	zapl "sigs.k8s.io/controller-runtime/pkg/log/zap"
+	crmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
 
+	"github.com/joelanford/helm-operator/internal/metrics"
 	"github.com/joelanford/helm-operator/internal/version"
 	"github.com/joelanford/helm-operator/pkg/annotation"
 	"github.com/joelanford/helm-operator/pkg/manager"
@@ -96,6 +98,8 @@ func printVersion() {
 func (r *run) run(cmd *cobra.Command) {
 	printVersion()
 
+	metrics.RegisterBuildInfo(crmetrics.Registry)
+
 	// Deprecated: OPERATOR_NAME environment variable is an artifact of the legacy operator-sdk project scaffolding.
 	//   Flag `--leader-election-id` should be used instead.
 	if operatorName, found := os.LookupEnv("OPERATOR_NAME"); found {

internal/metrics/metrics.go

@@ -0,0 +1,45 @@
+// Copyright 2021 The Operator-SDK 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 metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	helmVersion "github.com/joelanford/helm-operator/internal/version"
+)
+
+const (
+	subsystem = "helm_operator"
+)
+
+var (
+	buildInfo = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Subsystem: subsystem,
+			Name:      "build_info",
+			Help:      "Build information for the helm-operator binary",
+			ConstLabels: map[string]string{
+				"commit":  helmVersion.GitCommit,
+				"version": helmVersion.GitVersion,
+			},
+		},
+	)
+)
+
+//RegisterBuildInfo registers buildInfo Collector to be included in metrics collection
+func RegisterBuildInfo(r prometheus.Registerer) {
+	buildInfo.Set(1)
+	r.MustRegister(buildInfo)
+}