Limit node-exporter scope, deprecated collectors

collector/collector.go

@@ -16,20 +16,19 @@ package collector
 
 import (
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/log"
 )
 
 const Namespace = "node"
 
 var Factories = make(map[string]func() (Collector, error))
 
+func warnDeprecated(collector string) {
+	log.Warnf("The %s collector is deprecated and will be removed in the future!", collector)
+}
+
 // Interface a collector has to implement.
 type Collector interface {
 	// Get new metrics and expose them via prometheus registry.
 	Update(ch chan<- prometheus.Metric) (err error)
 }
-
-// TODO: Instead of periodically call Update, a Collector could be implemented
-// as a real prometheus.Collector that only gathers metrics when
-// scraped. (However, for metric gathering that takes very long, it might
-// actually be better to do them proactively before scraping to minimize scrape
-// time.)

collector/gmond.go

@@ -48,6 +48,7 @@ var illegalCharsRE = regexp.MustCompile(`[^a-zA-Z0-9_]`)
 
 // Takes a prometheus registry and returns a new Collector scraping ganglia.
 func NewGmondCollector() (Collector, error) {
+	warnDeprecated("gmond")
 	c := gmondCollector{
 		metrics: map[string]*prometheus.GaugeVec{},
 	}

collector/megacli.go

@@ -50,6 +50,7 @@ func init() {
 // Takes a prometheus registry and returns a new Collector exposing
 // RAID status through megacli.
 func NewMegaCliCollector() (Collector, error) {
+	warnDeprecated("megacli")
 	return &megaCliCollector{
 		cli: *megacliCommand,
 		driveTemperature: prometheus.NewGaugeVec(prometheus.GaugeOpts{

collector/ntp.go

@@ -41,6 +41,7 @@ func init() {
 // Takes a prometheus registry and returns a new Collector exposing
 // the offset between ntp and the current system time.
 func NewNtpCollector() (Collector, error) {
+	warnDeprecated("ntp")
 	if *ntpServer == "" {
 		return nil, fmt.Errorf("no NTP server specified, see -collector.ntp.server")
 	}