Remove support for expvar-backed metrics

cmd/agent/main.go

@@ -62,7 +62,7 @@ func main() {
  Namespace(metrics.NSOptions{Name: "jaeger"}).
  Namespace(metrics.NSOptions{Name: "agent"})
  mFactory := fork.New("internal",
- expvar.NewFactory(10), // backend for internal opts
+ expvar.NewFactory(), // expvar backend to report settings
  baseFactory)
  version.NewInfoMetrics(mFactory)
 

cmd/all-in-one/main.go

@@ -97,7 +97,7 @@ by default uses only in-memory database.`,
  }
  logger := svc.Logger // shortcut
  baseFactory := fork.New("internal",
- expvar.NewFactory(10), // backend for internal opts
+ expvar.NewFactory(), // expvar backend to report settings
  svc.MetricsFactory.Namespace(metrics.NSOptions{Name: "jaeger"}))
  version.NewInfoMetrics(baseFactory)
  agentMetricsFactory := baseFactory.Namespace(metrics.NSOptions{Name: "agent"})

cmd/collector/main.go

@@ -74,7 +74,7 @@ func main() {
  logger := svc.Logger // shortcut
  baseFactory := svc.MetricsFactory.Namespace(metrics.NSOptions{Name: "jaeger"})
  metricsFactory := fork.New("internal",
- expvar.NewFactory(10), // backend for internal opts
+ expvar.NewFactory(), // expvar backend to report settings
  baseFactory.Namespace(metrics.NSOptions{Name: "collector"}))
  version.NewInfoMetrics(metricsFactory)
 

examples/hotrod/cmd/flags.go

@@ -21,9 +21,8 @@ import (
 )
 
 var (
- metricsBackend string
- otelExporter string // otlp, stdout
- verbose bool
+ otelExporter string // otlp, stdout
+ verbose bool
 
  fixDBConnDelay time.Duration
  fixDBConnDisableMutex bool
@@ -38,11 +37,8 @@ var (
  jaegerUI string
 )
 
-const expvarDepr = "(deprecated, will be removed after 2024-01-01 or in release v1.53.0, whichever is later) "
-
 // used by root command
 func addFlags(cmd *cobra.Command) {
- cmd.PersistentFlags().StringVarP(&metricsBackend, "metrics", "m", "prometheus", expvarDepr+"Metrics backend (expvar|prometheus). ")
  cmd.PersistentFlags().StringVarP(&otelExporter, "otel-exporter", "x", "otlp", "OpenTelemetry exporter (otlp|stdout)")
 
  cmd.PersistentFlags().DurationVarP(&fixDBConnDelay, "fix-db-query-delay", "D", 300*time.Millisecond, "Average latency of MySQL DB query")

examples/hotrod/cmd/root.go

@@ -24,7 +24,6 @@ import (
 
  "github.com/jaegertracing/jaeger/examples/hotrod/services/config"
  "github.com/jaegertracing/jaeger/internal/jaegerclientenv2otel"
- "github.com/jaegertracing/jaeger/internal/metrics/expvar"
  "github.com/jaegertracing/jaeger/internal/metrics/prometheus"
  "github.com/jaegertracing/jaeger/pkg/metrics"
 )
@@ -57,6 +56,8 @@ func init() {
 
 // onInitialize is called before the command is executed.
 func onInitialize() {
+ jaegerclientenv2otel.MapJaegerToOtelEnvVars(logger)
+
  zapOptions := []zap.Option{
  zap.AddStacktrace(zapcore.FatalLevel),
  zap.AddCallerSkip(1),
@@ -67,19 +68,8 @@ func onInitialize() {
  )
  }
  logger, _ = zap.NewDevelopment(zapOptions...)
+ metricsFactory = prometheus.New().Namespace(metrics.NSOptions{Name: "hotrod", Tags: nil})
 
- jaegerclientenv2otel.MapJaegerToOtelEnvVars(logger)
-
- switch metricsBackend {
- case "expvar":
- metricsFactory = expvar.NewFactory(10) // 10 buckets for histograms
- logger.Info("*** Using expvar as metrics backend " + expvarDepr)
- case "prometheus":
- metricsFactory = prometheus.New().Namespace(metrics.NSOptions{Name: "hotrod", Tags: nil})
- logger.Info("Using Prometheus as metrics backend")
- default:
- logger.Fatal("unsupported metrics backend " + metricsBackend)
- }
  if config.MySQLGetDelay != fixDBConnDelay {
  logger.Info("fix: overriding MySQL query delay", zap.Duration("old", config.MySQLGetDelay), zap.Duration("new", fixDBConnDelay))
  config.MySQLGetDelay = fixDBConnDelay

go.mod

@@ -14,7 +14,6 @@ require (
  github.com/dgraph-io/badger/v3 v3.2103.5
  github.com/elastic/go-elasticsearch/v8 v8.13.1
  github.com/fsnotify/fsnotify v1.7.0
- github.com/go-kit/kit v0.13.0
  github.com/go-logr/zapr v1.3.0
  github.com/gocql/gocql v1.3.2
  github.com/gogo/googleapis v1.4.1
@@ -84,7 +83,6 @@ require (
 
 require (
  github.com/IBM/sarama v1.43.2 // indirect
- github.com/VividCortex/gohistogram v1.0.0 // indirect
  github.com/aws/aws-sdk-go v1.53.2 // indirect
  github.com/beorn7/perks v1.0.1 // indirect
  github.com/cenkalti/backoff/v4 v4.3.0 // indirect

go.sum

@@ -12,8 +12,6 @@ github.com/Shopify/sarama v1.33.0 h1:2K4mB9M4fo46sAM7t6QTsmSO8dLX1OqznLM7vn3OjZ8
 github.com/Shopify/sarama v1.33.0/go.mod h1:lYO7LwEBkE0iAeTl94UfPSrDaavFzSFlmn+5isARATQ=
 github.com/Shopify/toxiproxy/v2 v2.3.0 h1:62YkpiP4bzdhKMH+6uC5E95y608k3zDwdzuBMsnn3uQ=
 github.com/Shopify/toxiproxy/v2 v2.3.0/go.mod h1:KvQTtB6RjCJY4zqNJn7C7JDFgsG5uoHYDirfUfpIm0c=
-github.com/VividCortex/gohistogram v1.0.0 h1:6+hBz+qvs0JOrrNhhmR7lFxo5sINxBCGXrdtl/UvroE=
-github.com/VividCortex/gohistogram v1.0.0/go.mod h1:Pf5mBqqDxYaXu3hDrrU+w6nw50o/4+TcAqDqk/vUH7g=
 github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af/go.mod h1:K08gAheRH3/J6wwsYMMT4xOr94bZjxIelGM0+d/wbFw=
 github.com/apache/thrift v0.20.0 h1:631+KvYbsBZxmuJjYwhezVsrfc/TbqtZV4QcxOX1fOI=
 github.com/apache/thrift v0.20.0/go.mod h1:hOk1BQqcp2OLzGsyVXdfMk7YFlMxK3aoEVhjD06QhB8=
@@ -93,8 +91,6 @@ github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4
 github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
 github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
-github.com/go-kit/kit v0.13.0 h1:OoneCcHKHQ03LfBpoQCUfCluwd2Vt3ohz+kvbJneZAU=
-github.com/go-kit/kit v0.13.0/go.mod h1:phqEHMMUbyrCFCTgH48JueqrM3md2HcAZ8N3XE4FKDg=
 github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=

internal/metrics/expvar/factory.go

@@ -18,17 +18,16 @@ package expvar
 import (
  "sort"
 
- kexpvar "github.com/go-kit/kit/metrics/expvar"
-
  "github.com/jaegertracing/jaeger/pkg/metrics"
 )
 
-// NewFactory creates a new metrics factory using go-kit expvar package.
-// buckets is the number of buckets to be used in histograms.
-// Custom buckets passed via options are not supported.
-func NewFactory(buckets int) metrics.Factory {
+// NewFactory creates a new metrics factory backed by expvar variables.
+// Histograms are not supported, only act as gauges.
+// This package is primarily used to expose config parameters / settings
+// via expvar variables for manual inspection, not for remove monitoring,
+// since they are usually emitted only once.
+func NewFactory() metrics.Factory {
  return &factory{
- buckets: buckets,
  scope: "",
  scopeSep: ".",
  tagsSep: ".",
@@ -38,8 +37,6 @@ func NewFactory(buckets int) metrics.Factory {
 }
 
 type factory struct {
- buckets int
-
  scope string
  tags map[string]string
  scopeSep string
@@ -96,34 +93,33 @@ func makeKey(name string, tags map[string]string, tagsSep string, tagKVSep strin
 func (f *factory) Counter(options metrics.Options) metrics.Counter {
  key := f.getKey(options.Name, options.Tags)
  return f.cache.getOrSetCounter(key, func() metrics.Counter {
- return NewCounter(kexpvar.NewCounter(key))
+ return NewCounter(key)
  })
 }
 
 func (f *factory) Gauge(options metrics.Options) metrics.Gauge {
  key := f.getKey(options.Name, options.Tags)
  return f.cache.getOrSetGauge(key, func() metrics.Gauge {
- return NewGauge(kexpvar.NewGauge(key))
+ return NewGauge(key)
  })
 }
 
 func (f *factory) Timer(options metrics.TimerOptions) metrics.Timer {
  key := f.getKey(options.Name, options.Tags)
  return f.cache.getOrSetTimer(key, func() metrics.Timer {
- return NewTimer(kexpvar.NewHistogram(key, f.buckets))
+ return NewTimer(key)
  })
 }
 
 func (f *factory) Histogram(options metrics.HistogramOptions) metrics.Histogram {
  key := f.getKey(options.Name, options.Tags)
  return f.cache.getOrSetHistogram(key, func() metrics.Histogram {
- return NewHistogram(kexpvar.NewHistogram(key, f.buckets))
+ return NewHistogram(key)
  })
 }
 
 func (f *factory) Namespace(options metrics.NSOptions) metrics.Factory {
  return &factory{
- buckets: f.buckets,
  scope: f.subScope(options.Name),
  tags: f.mergeTags(options.Tags),
  scopeSep: f.scopeSep,

internal/metrics/expvar/factory_test.go

@@ -40,29 +40,28 @@ var (
 )
 
 func TestFactory(t *testing.T) {
- buckets := []float64{10, 20, 30, 40, 50, 60}
  testCases := []struct {
  name string
  tags map[string]string
- buckets []float64
  durationBuckets []time.Duration
  namespace string
  nsTags map[string]string
  fullName string
  expectedCounter string
  }{
- {name: "x", fullName: "%sx", buckets: buckets},
- {tags: tagsX, fullName: "%s.x_y", buckets: buckets},
- {name: "x", tags: tagsA, fullName: "%sx.a_b", buckets: buckets},
- {namespace: "y", fullName: "y.%s", buckets: buckets},
- {nsTags: tagsA, fullName: "%s.a_b", buckets: buckets},
- {namespace: "y", nsTags: tagsX, fullName: "y.%s.x_y", buckets: buckets},
- {name: "x", namespace: "y", nsTags: tagsX, fullName: "y.%sx.x_y", buckets: buckets},
- {name: "x", tags: tagsX, namespace: "y", nsTags: tagsX, fullName: "y.%sx.x_y", expectedCounter: "84", buckets: buckets},
- {name: "x", tags: tagsA, namespace: "y", nsTags: tagsX, fullName: "y.%sx.a_b.x_y", buckets: buckets},
- {name: "x", tags: tagsX, namespace: "y", nsTags: tagsA, fullName: "y.%sx.a_b.x_y", expectedCounter: "84", buckets: buckets},
+ {name: "x", fullName: "%sx"},
+ {name: "x", fullName: "%sx", expectedCounter: "84"}, // same as above to validate that the same vars are ok to create
+ {tags: tagsX, fullName: "%s.x_y"},
+ {name: "x", tags: tagsA, fullName: "%sx.a_b"},
+ {namespace: "y", fullName: "y.%s"},
+ {nsTags: tagsA, fullName: "%s.a_b"},
+ {namespace: "y", nsTags: tagsX, fullName: "y.%s.x_y"},
+ {name: "x", namespace: "y", nsTags: tagsX, fullName: "y.%sx.x_y"},
+ {name: "x", tags: tagsX, namespace: "y", nsTags: tagsX, fullName: "y.%sx.x_y", expectedCounter: "84"},
+ {name: "x", tags: tagsA, namespace: "y", nsTags: tagsX, fullName: "y.%sx.a_b.x_y"},
+ {name: "x", tags: tagsX, namespace: "y", nsTags: tagsA, fullName: "y.%sx.a_b.x_y", expectedCounter: "84"},
  }
- f := NewFactory(2)
+ f := NewFactory()
  for _, testCase := range testCases {
  t.Run("", func(t *testing.T) {
  if testCase.expectedCounter == "" {
@@ -89,9 +88,8 @@ func TestFactory(t *testing.T) {
  Buckets: testCase.durationBuckets,
  })
  histogram := ff.Histogram(metrics.HistogramOptions{
- Name: histogramPrefix + testCase.name,
- Tags: testCase.tags,
- Buckets: testCase.buckets,
+ Name: histogramPrefix + testCase.name,
+ Tags: testCase.tags,
  })
 
  // register second time, should not panic
@@ -109,20 +107,19 @@ func TestFactory(t *testing.T) {
  Buckets: testCase.durationBuckets,
  })
  ff.Histogram(metrics.HistogramOptions{
- Name: histogramPrefix + testCase.name,
- Tags: testCase.tags,
- Buckets: testCase.buckets,
+ Name: histogramPrefix + testCase.name,
+ Tags: testCase.tags,
  })
 
  counter.Inc(42)
  gauge.Update(42)
  timer.Record(42 * time.Millisecond)
- histogram.Record(42)
+ histogram.Record(42.42)
 
  assertExpvar(t, fmt.Sprintf(testCase.fullName, counterPrefix), testCase.expectedCounter)
  assertExpvar(t, fmt.Sprintf(testCase.fullName, gaugePrefix), "42")
- assertExpvar(t, fmt.Sprintf(testCase.fullName, timerPrefix)+".p99", "0.042")
- assertExpvar(t, fmt.Sprintf(testCase.fullName, histogramPrefix)+".p99", "42")
+ assertExpvar(t, fmt.Sprintf(testCase.fullName, timerPrefix)+"_ns", "42000000")
+ assertExpvar(t, fmt.Sprintf(testCase.fullName, histogramPrefix), "42.42")
  })
  }
 }

internal/metrics/expvar/metrics.go

@@ -16,67 +16,70 @@
 package expvar
 
 import (
+ "expvar"
+ "strings"
  "time"
-
- kit "github.com/go-kit/kit/metrics"
 )
 
 // Counter is an adapter from go-kit Counter to jaeger-lib Counter
 type Counter struct {
- counter kit.Counter
+ intVar *expvar.Int
 }
 
 // NewCounter creates a new Counter
-func NewCounter(counter kit.Counter) *Counter {
- return &Counter{counter: counter}
+func NewCounter(key string) *Counter {
+ return &Counter{intVar: expvar.NewInt(key)}
 }
 
 // Inc adds the given value to the counter.
 func (c *Counter) Inc(delta int64) {
- c.counter.Add(float64(delta))
+ c.intVar.Add(delta)
 }
 
 // Gauge is an adapter from go-kit Gauge to jaeger-lib Gauge
 type Gauge struct {
- gauge kit.Gauge
+ intVar *expvar.Int
 }
 
 // NewGauge creates a new Gauge
-func NewGauge(gauge kit.Gauge) *Gauge {
- return &Gauge{gauge: gauge}
+func NewGauge(key string) *Gauge {
+ return &Gauge{intVar: expvar.NewInt(key)}
 }
 
 // Update the gauge to the value passed in.
 func (g *Gauge) Update(value int64) {
- g.gauge.Set(float64(value))
+ g.intVar.Set(value)
 }
 
-// Timer is an adapter from go-kit Histogram to jaeger-lib Timer
+// Timer only records the latest value (like a Gauge).
 type Timer struct {
- hist kit.Histogram
+ intVar *expvar.Int
 }
 
-// NewTimer creates a new Timer
-func NewTimer(hist kit.Histogram) *Timer {
- return &Timer{hist: hist}
+// NewTimer creates a new Timer.
+func NewTimer(key string) *Timer {
+ if !strings.HasSuffix(key, "_ns") {
+ key += "_ns"
+ }
+ return &Timer{intVar: expvar.NewInt(key)}
 }
 
 // Record saves the time passed in.
 func (t *Timer) Record(delta time.Duration) {
- t.hist.Observe(delta.Seconds())
+ t.intVar.Set(delta.Nanoseconds())
 }
 
-// Histogram is an adapter from go-kit Histogram to jaeger-lib Histogram
+// Histogram only records the latest value (like a Gauge).
 type Histogram struct {
- hist kit.Histogram
+ floatVar *expvar.Float
 }
 
 // NewHistogram creates a new Histogram
-func NewHistogram(hist kit.Histogram) *Histogram {
- return &Histogram{hist: hist}
+func NewHistogram(key string) *Histogram {
+ return &Histogram{floatVar: expvar.NewFloat(key)}
 }
 
 // Record saves the value passed in.
 func (t *Histogram) Record(value float64) {
- t.hist.Observe(value)
+ t.floatVar.Set(value)
 }