Add a build info metric (prometheus-community#323)

* Add a build info metric

Add a standard Prometheus build info metric to make monitoring rollouts
easier.

* Update prometheus vendoring.

* Fix build error

Fix missing bool in builtinMetricMaps.

Signed-off-by: Ben Kochie <[email protected]>
(cherry picked from commit aeec47e)

Author: SuperQ

cmd/postgres_exporter/postgres_exporter.go

@@ -31,6 +31,52 @@ import (
 	"github.com/go-kit/log/level"
 	"github.com/lib/pq"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/prometheus/common/log"
+	"github.com/prometheus/common/version"
+	"gopkg.in/alecthomas/kingpin.v2"
+	"gopkg.in/yaml.v2"
+)
+
+// Branch is set during build to the git branch.
+var Branch string
+
+// BuildDate is set during build to the ISO-8601 date and time.
+var BuildDate string
+
+// Revision is set during build to the git commit revision.
+var Revision string
+
+// Version is set during build to the git describe version
+// (semantic version)-(commitish) form.
+var Version = "0.0.1-rev"
+
+// VersionShort is set during build to the semantic version.
+var VersionShort = "0.0.1"
+
+var (
+	listenAddress          = kingpin.Flag("web.listen-address", "Address to listen on for web interface and telemetry.").Default(":9187").Envar("PG_EXPORTER_WEB_LISTEN_ADDRESS").String()
+	metricPath             = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").Envar("PG_EXPORTER_WEB_TELEMETRY_PATH").String()
+	disableDefaultMetrics  = kingpin.Flag("disable-default-metrics", "Do not include default metrics.").Default("false").Envar("PG_EXPORTER_DISABLE_DEFAULT_METRICS").Bool()
+	disableSettingsMetrics = kingpin.Flag("disable-settings-metrics", "Do not include pg_settings metrics.").Default("false").Envar("PG_EXPORTER_DISABLE_SETTINGS_METRICS").Bool()
+	autoDiscoverDatabases  = kingpin.Flag("auto-discover-databases", "Whether to discover the databases on a server dynamically.").Default("false").Envar("PG_EXPORTER_AUTO_DISCOVER_DATABASES").Bool()
+	queriesPath            = kingpin.Flag("extend.query-path", "Path to custom queries to run.").Default("").Envar("PG_EXPORTER_EXTEND_QUERY_PATH").String()
+	onlyDumpMaps           = kingpin.Flag("dumpmaps", "Do not run, simply dump the maps.").Bool()
+	constantLabelsList     = kingpin.Flag("constantLabels", "A list of label=value separated by comma(,).").Default("").Envar("PG_EXPORTER_CONSTANT_LABELS").String()
+	excludeDatabases       = kingpin.Flag("exclude-databases", "A list of databases to remove when autoDiscoverDatabases is enabled").Default("").Envar("PG_EXPORTER_EXCLUDE_DATABASES").String()
+)
+
+// Metric name parts.
+const (
+	// Namespace for all metrics.
+	namespace = "pg"
+	// Subsystems.
+	exporter = "exporter"
+	// Metric label used for static string data thats handy to send to Prometheus
+	// e.g. version
+	staticLabelName = "static"
+	// Metric label used for server identification.
+	serverLabelName = "server"
 )
 
 // ColumnUsage should be one of several enum values which describe how a
@@ -896,6 +942,13 @@ func main() {
 		exporter.servers.Close()
 	}()
 
+	// Setup build info metric.
+	version.Branch = Branch
+	version.BuildDate = BuildDate
+	version.Revision = Revision
+	version.Version = VersionShort
+	prometheus.MustRegister(version.NewCollector("postgres_exporter"))
+
 	prometheus.MustRegister(exporter)
 
 	http.Handle(*metricPath, promhttp.Handler())