feat(metrics): Allow disabling exporter metrics

Fixes #2
pdf · Sep 4, 2021 · 1ca8717 · 1ca8717
1 parent 066c7d2
commit 1ca8717
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Showing 2 changed files with 44 additions and 27 deletions.
diff --git a/collector/zfs.go b/collector/zfs.go
@@ -28,25 +28,30 @@ func (c regexpCollection) MatchString(input string) bool {
 
 // ZFSConfig configures a ZFS collector
 type ZFSConfig struct {
-	Deadline time.Duration
-	Pools    []string
-	Excludes []string
-	Logger   log.Logger
+	DisableMetrics bool
+	Deadline       time.Duration
+	Pools          []string
+	Excludes       []string
+	Logger         log.Logger
 }
 
 // ZFS collector
 type ZFS struct {
-	Pools      []string
-	Collectors map[string]State
-	deadline   time.Duration
-	cache      *metricCache
-	ready      chan struct{}
-	logger     log.Logger
-	excludes   regexpCollection
+	Pools          []string
+	Collectors     map[string]State
+	disableMetrics bool
+	deadline       time.Duration
+	cache          *metricCache
+	ready          chan struct{}
+	logger         log.Logger
+	excludes       regexpCollection
 }
 
 // Describe implements the prometheus.Collector interface.
 func (c *ZFS) Describe(ch chan<- *prometheus.Desc) {
+	if c.disableMetrics {
+		return
+	}
 	ch <- scrapeDurationDesc
 	ch <- scrapeSuccessDesc
 }
@@ -207,6 +212,10 @@ func (c *ZFS) execute(ctx context.Context, name string, collector Collector, ch
 			success = 1
 		}
 	}
+
+	if c.disableMetrics {
+		return
+	}
 	ch <- metric{
 		name:       scrapeDurationDescName,
 		prometheus: prometheus.MustNewConstMetric(scrapeDurationDesc, prometheus.GaugeValue, duration.Seconds(), name),
@@ -228,12 +237,13 @@ func NewZFS(config ZFSConfig) (*ZFS, error) {
 	ready := make(chan struct{}, 1)
 	ready <- struct{}{}
 	return &ZFS{
-		deadline:   config.Deadline,
-		Pools:      config.Pools,
-		Collectors: collectorStates,
-		excludes:   excludes,
-		cache:      newMetricCache(),
-		ready:      ready,
-		logger:     config.Logger,
+		disableMetrics: config.DisableMetrics,
+		deadline:       config.Deadline,
+		Pools:          config.Pools,
+		Collectors:     collectorStates,
+		excludes:       excludes,
+		cache:          newMetricCache(),
+		ready:          ready,
+		logger:         config.Logger,
 	}, nil
 }
diff --git a/zfs_exporter.go b/zfs_exporter.go
@@ -18,11 +18,12 @@ import (
 
 func main() {
 	var (
-		listenAddress = kingpin.Flag("web.listen-address", "Address on which to expose metrics and web interface.").Default(":9134").String()
-		metricsPath   = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").String()
-		deadline      = kingpin.Flag("deadline", "Maximum duration that a collection should run before returning cached data. Should be set to a value shorter than your scrape timeout duration. The current collection run will continue and update the cache when complete (default: 8s)").Default("8s").Duration()
-		pools         = kingpin.Flag("pool", "Name of the pool(s) to collect, repeat for multiple pools (default: all pools).").Strings()
-		excludes      = kingpin.Flag("exclude", "Exclude datasets/snapshots/volumes that match the provided regex (e.g. '^rpool/docker/'), may be specified multiple times.").Strings()
+		listenAddress           = kingpin.Flag("web.listen-address", "Address on which to expose metrics and web interface.").Default(":9134").String()
+		metricsPath             = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").String()
+		metricsExporterDisabled = kingpin.Flag(`web.disable-exporter-metrics`, `Exclude metrics about the exporter itself (promhttp_*, process_*, go_*).`).Default(`false`).Bool()
+		deadline                = kingpin.Flag("deadline", "Maximum duration that a collection should run before returning cached data. Should be set to a value shorter than your scrape timeout duration. The current collection run will continue and update the cache when complete (default: 8s)").Default("8s").Duration()
+		pools                   = kingpin.Flag("pool", "Name of the pool(s) to collect, repeat for multiple pools (default: all pools).").Strings()
+		excludes                = kingpin.Flag("exclude", "Exclude datasets/snapshots/volumes that match the provided regex (e.g. '^rpool/docker/'), may be specified multiple times.").Strings()
 	)
 
 	promlogConfig := &promlog.Config{}
@@ -36,16 +37,22 @@ func main() {
 	_ = level.Info(logger).Log("msg", "Build context", "context", version.BuildContext())
 
 	c, err := collector.NewZFS(collector.ZFSConfig{
-		Deadline: *deadline,
-		Pools:    *pools,
-		Excludes: *excludes,
-		Logger:   logger,
+		DisableMetrics: *metricsExporterDisabled,
+		Deadline:       *deadline,
+		Pools:          *pools,
+		Excludes:       *excludes,
+		Logger:         logger,
 	})
 	if err != nil {
 		_ = level.Error(logger).Log("msg", "Error creating an exporter", "err", err)
 		os.Exit(1)
 	}
 
+	if *metricsExporterDisabled {
+		r := prometheus.NewRegistry()
+		prometheus.DefaultRegisterer = r
+		prometheus.DefaultGatherer = r
+	}
 	prometheus.MustRegister(c)
 	prometheus.MustRegister(version.NewCollector("zfs_exporter"))