kvprober: add metrics to the registry & catalog

This commit adds the kvprober metrics to the registry so they are
exported at the prometheus endpoint and tracked in CRDB's time-series
DB. This commit also adds the kvprober metrics to the catalog since
that is required by a unit test.

Release justification: Auxiliary system that is off by default.
Release note: None.

pkg/kv/kvprober/kvprober.go

@@ -39,10 +39,9 @@ type Prober struct {
 	settings   *cluster.Settings
 	// planner is an interface for selecting a range to probe.
 	planner planner
-
-	// Metrics wraps up the set of prometheus metrics that the prober sets. The
+	// metrics wraps up the set of prometheus metrics that the prober sets; the
 	// goal of the prober IS to populate these metrics.
-	Metrics Metrics
+	metrics Metrics
 }
 
 // Opts provides knobs to control kvprober.Prober.
@@ -113,7 +112,7 @@ func NewProber(opts Opts) *Prober {
 		settings:   opts.Settings,
 
 		planner: newMeta2Planner(opts.DB, opts.Settings),
-		Metrics: Metrics{
+		metrics: Metrics{
 			ReadProbeAttempts: metric.NewCounter(metaReadProbeAttempts),
 			ReadProbeFailures: metric.NewCounter(metaReadProbeFailures),
 			ReadProbeLatency:  metric.NewLatency(metaReadProbeLatency, opts.HistogramWindowInterval),
@@ -123,6 +122,11 @@ func NewProber(opts Opts) *Prober {
 	}
 }
 
+// Metrics returns a struct which contains the kvprober metrics.
+func (p *Prober) Metrics() Metrics {
+	return p.metrics
+}
+
 // Start causes kvprober to start probing KV. Start returns immediately. Start
 // returns an error only if stopper.RunAsyncTask returns an error.
 func (p *Prober) Start(ctx context.Context, stopper *stop.Stopper) error {
@@ -170,12 +174,12 @@ func (p *Prober) probe(ctx context.Context, db dbGet) {
 		return
 	}
 
-	p.Metrics.ProbePlanAttempts.Inc(1)
+	p.metrics.ProbePlanAttempts.Inc(1)
 
 	step, err := p.planner.next(ctx)
 	if err != nil {
 		log.Health.Errorf(ctx, "can't make a plan: %v", err)
-		p.Metrics.ProbePlanFailures.Inc(1)
+		p.metrics.ProbePlanFailures.Inc(1)
 		return
 	}
 
@@ -186,7 +190,7 @@ func (p *Prober) probe(ctx context.Context, db dbGet) {
 	// ProbePlanFailures. This would probably be a ticket alerting as
 	// the impact is more low visibility into possible failures than a high
 	// impact production issue.
-	p.Metrics.ReadProbeAttempts.Inc(1)
+	p.metrics.ReadProbeAttempts.Inc(1)
 
 	start := timeutil.Now()
 
@@ -204,15 +208,15 @@ func (p *Prober) probe(ctx context.Context, db dbGet) {
 	if err != nil {
 		// TODO(josh): Write structured events with log.Structured.
 		log.Health.Errorf(ctx, "kv.Get(%s), r=%v failed with: %v", step.StartKey, step.RangeID, err)
-		p.Metrics.ReadProbeFailures.Inc(1)
+		p.metrics.ReadProbeFailures.Inc(1)
 		return
 	}
 
 	d := timeutil.Since(start)
 	log.Health.Infof(ctx, "kv.Get(%s), r=%v returned success in %v", step.StartKey, step.RangeID, d)
 
 	// Latency of failures is not recorded. They are counted as failures tho.
-	p.Metrics.ReadProbeLatency.RecordValue(d.Nanoseconds())
+	p.metrics.ReadProbeLatency.RecordValue(d.Nanoseconds())
 }
 
 // Returns a random duration pulled from the uniform distribution given below:

pkg/kv/kvprober/kvprober_integration_test.go

@@ -53,8 +53,8 @@ func TestProberDoesReads(t *testing.T) {
 
 		time.Sleep(100 * time.Millisecond)
 
-		require.Zero(t, p.Metrics.ProbePlanAttempts.Count())
-		require.Zero(t, p.Metrics.ReadProbeAttempts.Count())
+		require.Zero(t, p.Metrics().ProbePlanAttempts.Count())
+		require.Zero(t, p.Metrics().ReadProbeAttempts.Count())
 	})
 
 	t.Run("happy path", func(t *testing.T) {
@@ -67,13 +67,13 @@ func TestProberDoesReads(t *testing.T) {
 		require.NoError(t, p.Start(ctx, s.Stopper()))
 
 		testutils.SucceedsSoon(t, func() error {
-			if p.Metrics.ReadProbeAttempts.Count() < int64(50) {
-				return errors.Newf("probe count too low: %v", p.Metrics.ReadProbeAttempts.Count())
+			if p.Metrics().ReadProbeAttempts.Count() < int64(50) {
+				return errors.Newf("probe count too low: %v", p.Metrics().ReadProbeAttempts.Count())
 			}
 			return nil
 		})
-		require.Zero(t, p.Metrics.ReadProbeFailures.Count())
-		require.Zero(t, p.Metrics.ProbePlanFailures.Count())
+		require.Zero(t, p.Metrics().ReadProbeFailures.Count())
+		require.Zero(t, p.Metrics().ProbePlanFailures.Count())
 	})
 
 	t.Run("a single range is unavailable", func(t *testing.T) {
@@ -101,12 +101,12 @@ func TestProberDoesReads(t *testing.T) {
 		// TODO(josh): Once structured logging is in, can check that failures
 		// involved only the time-series range.
 		testutils.SucceedsSoon(t, func() error {
-			if p.Metrics.ReadProbeFailures.Count() < int64(2) {
-				return errors.Newf("error count too low: %v", p.Metrics.ReadProbeFailures.Count())
+			if p.Metrics().ReadProbeFailures.Count() < int64(2) {
+				return errors.Newf("error count too low: %v", p.Metrics().ReadProbeFailures.Count())
 			}
 			return nil
 		})
-		require.Zero(t, p.Metrics.ProbePlanFailures.Count())
+		require.Zero(t, p.Metrics().ProbePlanFailures.Count())
 	})
 
 	t.Run("all ranges are unavailable for Gets", func(t *testing.T) {
@@ -148,9 +148,9 @@ func TestProberDoesReads(t *testing.T) {
 		}
 
 		// Expect all probes to fail but planning to succeed.
-		require.Equal(t, int64(10), p.Metrics.ReadProbeAttempts.Count())
-		require.Equal(t, int64(10), p.Metrics.ReadProbeFailures.Count())
-		require.Zero(t, p.Metrics.ProbePlanFailures.Count())
+		require.Equal(t, int64(10), p.Metrics().ReadProbeAttempts.Count())
+		require.Equal(t, int64(10), p.Metrics().ReadProbeFailures.Count())
+		require.Zero(t, p.Metrics().ProbePlanFailures.Count())
 	})
 }
 

pkg/kv/kvprober/kvprober_test.go

@@ -40,10 +40,10 @@ func TestProbe(t *testing.T) {
 
 		p.probe(ctx, m)
 
-		require.Zero(t, p.Metrics.ProbePlanAttempts.Count())
-		require.Zero(t, p.Metrics.ReadProbeAttempts.Count())
-		require.Zero(t, p.Metrics.ProbePlanFailures.Count())
-		require.Zero(t, p.Metrics.ReadProbeFailures.Count())
+		require.Zero(t, p.Metrics().ProbePlanAttempts.Count())
+		require.Zero(t, p.Metrics().ReadProbeAttempts.Count())
+		require.Zero(t, p.Metrics().ProbePlanFailures.Count())
+		require.Zero(t, p.Metrics().ReadProbeFailures.Count())
 	})
 
 	t.Run("happy path", func(t *testing.T) {
@@ -53,10 +53,10 @@ func TestProbe(t *testing.T) {
 
 		p.probe(ctx, m)
 
-		require.Equal(t, int64(1), p.Metrics.ProbePlanAttempts.Count())
-		require.Equal(t, int64(1), p.Metrics.ReadProbeAttempts.Count())
-		require.Zero(t, p.Metrics.ProbePlanFailures.Count())
-		require.Zero(t, p.Metrics.ReadProbeFailures.Count())
+		require.Equal(t, int64(1), p.Metrics().ProbePlanAttempts.Count())
+		require.Equal(t, int64(1), p.Metrics().ReadProbeAttempts.Count())
+		require.Zero(t, p.Metrics().ProbePlanFailures.Count())
+		require.Zero(t, p.Metrics().ReadProbeFailures.Count())
 	})
 
 	t.Run("planning fails", func(t *testing.T) {
@@ -70,10 +70,10 @@ func TestProbe(t *testing.T) {
 
 		p.probe(ctx, m)
 
-		require.Equal(t, int64(1), p.Metrics.ProbePlanAttempts.Count())
-		require.Zero(t, p.Metrics.ReadProbeAttempts.Count())
-		require.Equal(t, int64(1), p.Metrics.ProbePlanFailures.Count())
-		require.Zero(t, p.Metrics.ReadProbeFailures.Count())
+		require.Equal(t, int64(1), p.Metrics().ProbePlanAttempts.Count())
+		require.Zero(t, p.Metrics().ReadProbeAttempts.Count())
+		require.Equal(t, int64(1), p.Metrics().ProbePlanFailures.Count())
+		require.Zero(t, p.Metrics().ReadProbeFailures.Count())
 	})
 
 	t.Run("get fails", func(t *testing.T) {
@@ -86,10 +86,10 @@ func TestProbe(t *testing.T) {
 
 		p.probe(ctx, m)
 
-		require.Equal(t, int64(1), p.Metrics.ProbePlanAttempts.Count())
-		require.Equal(t, int64(1), p.Metrics.ReadProbeAttempts.Count())
-		require.Zero(t, p.Metrics.ProbePlanFailures.Count())
-		require.Equal(t, int64(1), p.Metrics.ReadProbeFailures.Count())
+		require.Equal(t, int64(1), p.Metrics().ProbePlanAttempts.Count())
+		require.Equal(t, int64(1), p.Metrics().ReadProbeAttempts.Count())
+		require.Zero(t, p.Metrics().ProbePlanFailures.Count())
+		require.Equal(t, int64(1), p.Metrics().ReadProbeFailures.Count())
 	})
 }
 

pkg/server/server.go

@@ -652,6 +652,7 @@ func NewServer(cfg Config, stopper *stop.Stopper) (*Server, error) {
 		Settings:                st,
 		HistogramWindowInterval: cfg.HistogramWindowInterval(),
 	})
+	registry.AddMetricStruct(kvProber.Metrics())
 
 	sqlServer, err := newSQLServer(ctx, sqlServerArgs{
 		sqlServerOptionalKVArgs: sqlServerOptionalKVArgs{

pkg/ts/catalog/chart_catalog.go

@@ -575,6 +575,26 @@ var charts = []sectionDescription{
 			},
 		},
 	},
+	{
+		Organization: [][]string{{KVTransactionLayer, "Prober"}}, Charts: []chartDescription{
+			{
+				Title: "Availability",
+				Metrics: []string{
+					"kv.prober.planning_attempts",
+					"kv.prober.planning_failures",
+					"kv.prober.read.attempts",
+					"kv.prober.read.failures",
+				},
+				AxisLabel: "Probes",
+			},
+			{
+				Title: "Latency",
+				Metrics: []string{
+					"kv.prober.read.latency",
+				},
+			},
+		},
+	},
 	{
 		Organization: [][]string{
 			{KVTransactionLayer, "Clocks"},