silently ignore certain unsupported metric types

go/stats/export.go

@@ -149,50 +149,15 @@ func emitToBackend(emitPeriod *time.Duration) {
 	}
 }
 
-// Float is expvar.Float+Get+hook
-type Float struct {
-	mu sync.Mutex
-	f  float64
-}
-
-// NewFloat creates a new Float and exports it.
-func NewFloat(name string) *Float {
-	v := new(Float)
-	publish(name, v)
-	return v
-}
-
-// Add adds the provided value to the Float
-func (v *Float) Add(delta float64) {
-	v.mu.Lock()
-	v.f += delta
-	v.mu.Unlock()
-}
-
-// Set sets the value
-func (v *Float) Set(value float64) {
-	v.mu.Lock()
-	v.f = value
-	v.mu.Unlock()
-}
-
-// Get returns the value
-func (v *Float) Get() float64 {
-	v.mu.Lock()
-	f := v.f
-	v.mu.Unlock()
-	return f
-}
-
-// String is the implementation of expvar.var
-func (v *Float) String() string {
-	return strconv.FormatFloat(v.Get(), 'g', -1, 64)
-}
-
 // FloatFunc converts a function that returns
 // a float64 as an expvar.
 type FloatFunc func() float64
 
+// Help returns the help string (undefined currently)
+func (f FloatFunc) Help() string {
+	return "help"
+}
+
 // String is the implementation of expvar.var
 func (f FloatFunc) String() string {
 	return strconv.FormatFloat(f(), 'g', -1, 64)
@@ -255,41 +220,6 @@ func PublishJSONFunc(name string, f func() string) {
 	publish(name, JSONFunc(f))
 }
 
-// StringMap is a map of string -> string
-type StringMap struct {
-	mu     sync.Mutex
-	values map[string]string
-}
-
-// NewStringMap returns a new StringMap
-func NewStringMap(name string) *StringMap {
-	v := &StringMap{values: make(map[string]string)}
-	publish(name, v)
-	return v
-}
-
-// Set will set a value (existing or not)
-func (v *StringMap) Set(name, value string) {
-	v.mu.Lock()
-	v.values[name] = value
-	v.mu.Unlock()
-}
-
-// Get will return the value, or "" f not set.
-func (v *StringMap) Get(name string) string {
-	v.mu.Lock()
-	s := v.values[name]
-	v.mu.Unlock()
-	return s
-}
-
-// String is the implementation of expvar.Var
-func (v *StringMap) String() string {
-	v.mu.Lock()
-	defer v.mu.Unlock()
-	return stringMapToString(v.values)
-}
-
 // StringMapFunc is the function equivalent of StringMap
 type StringMapFunc func() map[string]string
 

go/stats/export_test.go

@@ -35,41 +35,6 @@ func TestNoHook(t *testing.T) {
 	}
 }
 
-func TestFloat(t *testing.T) {
-	var gotname string
-	var gotv *Float
-	clear()
-	Register(func(name string, v expvar.Var) {
-		gotname = name
-		gotv = v.(*Float)
-	})
-	v := NewFloat("Float")
-	if gotname != "Float" {
-		t.Errorf("want Float, got %s", gotname)
-	}
-	if gotv != v {
-		t.Errorf("want %#v, got %#v", v, gotv)
-	}
-	v.Set(5.1)
-	if v.Get() != 5.1 {
-		t.Errorf("want 5.1, got %v", v.Get())
-	}
-	v.Add(1.0)
-	if v.Get() != 6.1 {
-		t.Errorf("want 6.1, got %v", v.Get())
-	}
-	if v.String() != "6.1" {
-		t.Errorf("want 6.1, got %v", v.Get())
-	}
-
-	f := FloatFunc(func() float64 {
-		return 1.234
-	})
-	if f.String() != "1.234" {
-		t.Errorf("want 1.234, got %v", f.String())
-	}
-}
-
 func TestString(t *testing.T) {
 	var gotname string
 	var gotv *String
@@ -129,42 +94,25 @@ func f() string {
 	return "abcd"
 }
 
+type expvarFunc func() string
+
+func (f expvarFunc) String() string {
+	return f()
+}
+
 func TestPublishFunc(t *testing.T) {
 	var gotname string
-	var gotv JSONFunc
+	var gotv expvarFunc
 	clear()
 	Register(func(name string, v expvar.Var) {
 		gotname = name
-		gotv = v.(JSONFunc)
+		gotv = v.(expvarFunc)
 	})
-	PublishJSONFunc("Myfunc", f)
+	publish("Myfunc", expvarFunc(f))
 	if gotname != "Myfunc" {
 		t.Errorf("want Myfunc, got %s", gotname)
 	}
 	if gotv.String() != f() {
 		t.Errorf("want %v, got %#v", f(), gotv())
 	}
 }
-
-func TestStringMap(t *testing.T) {
-	clear()
-	c := NewStringMap("stringmap1")
-	c.Set("c1", "val1")
-	c.Set("c2", "val2")
-	c.Set("c2", "val3")
-	want1 := `{"c1": "val1", "c2": "val3"}`
-	want2 := `{"c2": "val3", "c1": "val1"}`
-	if s := c.String(); s != want1 && s != want2 {
-		t.Errorf("want %s or %s, got %s", want1, want2, s)
-	}
-
-	f := StringMapFunc(func() map[string]string {
-		return map[string]string{
-			"c1": "val1",
-			"c2": "val3",
-		}
-	})
-	if s := f.String(); s != want1 && s != want2 {
-		t.Errorf("want %s or %s, got %s", want1, want2, s)
-	}
-}

go/stats/influxdbbackend/influxdb_backend.go

@@ -94,8 +94,6 @@ func (backend *InfluxDBBackend) PushAll() error {
 // for arbitrary dict values (as tags).
 func statToValue(v expvar.Var) interface{} {
 	switch v := v.(type) {
-	case *stats.Float:
-		return v.Get()
 	case *stats.Counter:
 		return v.Get()
 	case stats.FloatFunc:

go/stats/opentsdb/opentsdb.go

@@ -181,8 +181,6 @@ func (dc *dataCollector) addFloat(metric string, val float64, tags map[string]st
 func (dc *dataCollector) addExpVar(kv expvar.KeyValue) {
 	k := kv.Key
 	switch v := kv.Value.(type) {
-	case *stats.Float:
-		dc.addFloat(k, v.Get(), nil)
 	case stats.FloatFunc:
 		dc.addFloat(k, v(), nil)
 	case *stats.Counter:

go/stats/prometheusbackend/prometheusbackend.go

@@ -4,12 +4,11 @@ import (
 	"expvar"
 	"net/http"
 	"strings"
-	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"vitess.io/vitess/go/stats"
-	"vitess.io/vitess/go/vt/logutil"
+	"vitess.io/vitess/go/vt/log"
 )
 
 // PromBackend implements PullBackend using Prometheus as the backing metrics storage.
@@ -18,15 +17,13 @@ type PromBackend struct {
 }
 
 var (
-	be             PromBackend
-	logUnsupported *logutil.ThrottledLogger
+	be PromBackend
 )
 
 // Init initializes the Prometheus be with the given namespace.
 func Init(namespace string) {
 	http.Handle("/metrics", promhttp.Handler())
 	be.namespace = namespace
-	logUnsupported = logutil.NewThrottledLogger("PrometheusUnsupportedMetricType", 1*time.Minute)
 	stats.Register(be.publishPrometheusMetric)
 }
 
@@ -41,6 +38,8 @@ func (be PromBackend) publishPrometheusMetric(name string, v expvar.Var) {
 		newMetricFuncCollector(st, be.buildPromName(name), prometheus.GaugeValue, func() float64 { return float64(st.Get()) })
 	case *stats.GaugeFunc:
 		newMetricFuncCollector(st, be.buildPromName(name), prometheus.GaugeValue, func() float64 { return float64(st.F()) })
+	case stats.FloatFunc:
+		newMetricFuncCollector(st, be.buildPromName(name), prometheus.GaugeValue, func() float64 { return (st)() })
 	case *stats.CountersWithSingleLabel:
 		newCountersWithSingleLabelCollector(st, be.buildPromName(name), st.Label(), prometheus.CounterValue)
 	case *stats.CountersWithMultiLabels:
@@ -67,8 +66,11 @@ func (be PromBackend) publishPrometheusMetric(name string, v expvar.Var) {
 		newMultiTimingsCollector(st, be.buildPromName(name))
 	case *stats.Histogram:
 		newHistogramCollector(st, be.buildPromName(name))
+	case *stats.String, stats.StringFunc, stats.StringMapFunc, *stats.Rates:
+		// Silently ignore these types since they don't make sense to
+		// export to Prometheus' data model.
 	default:
-		logUnsupported.Infof("Not exporting to Prometheus an unsupported metric type of %T: %s", st, name)
+		log.Fatalf("prometheus: Metric type %T (seen for variable: %s) is not covered by type switch. Add it there and to all other plugins which register a NewVarHook.", st, name)
 	}
 }
 

go/stats/prometheusbackend/prometheusbackend_test.go

@@ -59,6 +59,13 @@ func TestPrometheusGaugeFunc(t *testing.T) {
 	checkHandlerForMetrics(t, name, -3)
 }
 
+func TestPrometheusFloatFunc(t *testing.T) {
+	name := "blah_floatfunc"
+
+	stats.Publish(name, stats.FloatFunc(func() float64 { return -4 }))
+	checkHandlerForMetrics(t, name, -4)
+}
+
 func TestPrometheusCounterDuration(t *testing.T) {
 	name := "blah_counterduration"