[Spanmetrics] Add events_total metric to get the measurement for list…

… of configured event attributes for a span (open-telemetry#27811)

**Description:**
We have an events section for a span. The details for all the exceptions
like exception.type and exception.message are recorded as Events for a
span. Right now, we don't have a feature to add event attributes to span
metrics.

The idea of this PR is to develop a feature which adds a new metric
`events_total` with a default set of dimensions like `service_name,
span_name, span_kind, status_code`. We can configure to add additional
set of dimensions like `exception.type` and `exception.message` which
will be fetched from the Events section for a span

**Link to tracking Issue:**
[27451](open-telemetry#27451)

---------

Co-authored-by: Albert <[email protected]>

.chloggen/events-metric-to-span-metrics.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: spanmetricsconnector
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add Events metric to span metrics connector that adds list of event attributes as dimensions
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [27451]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

connector/spanmetricsconnector/README.md

@@ -102,6 +102,9 @@ The following settings can be optionally configured:
 - `metrics_flush_interval` (default: `15s`): Defines the flush interval of the generated metrics.
 - `exemplars`: Use to configure how to attach exemplars to histograms
  - `enabled` (default: `false`): enabling will add spans as Exemplars.
+- `events`: Use to configure the events metric.
+ - `enabled`: (default: `false`): enabling will add the events metric.
+ - `dimensions`: (mandatory if `enabled`) the list of the span's event attributes to add as dimensions to the events metric, which will be included _on top of_ the common and configured `dimensions` for span and resource attributes.
 
 ## Examples
 
@@ -132,7 +135,12 @@ connectors:
  exclude_dimensions: ['status.code']
  dimensions_cache_size: 1000
  aggregation_temporality: "AGGREGATION_TEMPORALITY_CUMULATIVE" 
- metrics_flush_interval: 15s 
+ metrics_flush_interval: 15s
+ events:
+ enabled: true
+ dimensions:
+ - name: exception.type
+ - name: exception.message
 
 service:
  pipelines:

connector/spanmetricsconnector/config.go

@@ -58,6 +58,9 @@ type Config struct {
 
  // Exemplars defines the configuration for exemplars.
  Exemplars ExemplarsConfig `mapstructure:"exemplars"`
+
+ // Events defines the configuration for events section of spans.
+ Events EventsConfig `mapstructure:"events"`
 }
 
 type HistogramConfig struct {
@@ -80,13 +83,22 @@ type ExplicitHistogramConfig struct {
  Buckets []time.Duration `mapstructure:"buckets"`
 }
 
+type EventsConfig struct {
+ // Enabled is a flag to enable events.
+ Enabled bool `mapstructure:"enabled"`
+ // Dimensions defines the list of dimensions to add to the events metric.
+ Dimensions []Dimension `mapstructure:"dimensions"`
+}
+
 var _ component.ConfigValidator = (*Config)(nil)
 
 // Validate checks if the processor configuration is valid
 func (c Config) Validate() error {
- err := validateDimensions(c.Dimensions)
- if err != nil {
- return err
+ if err := validateDimensions(c.Dimensions); err != nil {
+ return fmt.Errorf("failed validating dimensions: %w", err)
+ }
+ if err := validateEventDimensions(c.Events.Enabled, c.Events.Dimensions); err != nil {
+ return fmt.Errorf("failed validating event dimensions: %w", err)
  }
 
  if c.DimensionsCacheSize <= 0 {
@@ -99,6 +111,7 @@ func (c Config) Validate() error {
  if c.Histogram.Explicit != nil && c.Histogram.Exponential != nil {
  return errors.New("use either `explicit` or `exponential` buckets histogram")
  }
+
  return nil
 }
 
@@ -127,3 +140,14 @@ func validateDimensions(dimensions []Dimension) error {
 
  return nil
 }
+
+// validateEventDimensions checks for empty and duplicates for the dimensions configured.
+func validateEventDimensions(enabled bool, dimensions []Dimension) error {
+ if !enabled {
+ return nil
+ }
+ if len(dimensions) == 0 {
+ return fmt.Errorf("no dimensions configured for events")
+ }
+ return validateDimensions(dimensions)
+}

connector/spanmetricsconnector/config_test.go

@@ -171,3 +171,47 @@ func TestValidateDimensions(t *testing.T) {
  })
  }
 }
+
+func TestValidateEventDimensions(t *testing.T) {
+ for _, tc := range []struct {
+ enabled bool
+ name string
+ dimensions []Dimension
+ expectedErr string
+ }{
+ {
+ enabled: false,
+ name: "disabled - no additional dimensions",
+ dimensions: []Dimension{},
+ },
+ {
+ enabled: true,
+ name: "enabled - no additional dimensions",
+ dimensions: []Dimension{},
+ expectedErr: "no dimensions configured for events",
+ },
+ {
+ enabled: true,
+ name: "enabled - no duplicate dimensions",
+ dimensions: []Dimension{{Name: "exception_type"}},
+ },
+ {
+ enabled: true,
+ name: "enabled - duplicate dimensions",
+ dimensions: []Dimension{
+ {Name: "exception_type"},
+ {Name: "exception_type"},
+ },
+ expectedErr: "duplicate dimension name exception_type",
+ },
+ } {
+ t.Run(tc.name, func(t *testing.T) {
+ err := validateEventDimensions(tc.enabled, tc.dimensions)
+ if tc.expectedErr != "" {
+ assert.EqualError(t, err, tc.expectedErr)
+ } else {
+ assert.NoError(t, err)
+ }
+ })
+ }
+}

connector/spanmetricsconnector/connector.go

@@ -36,6 +36,7 @@ const (
 
  metricNameDuration = "duration"
  metricNameCalls = "calls"
+ metricNameEvents = "events"
 
  defaultUnit = metrics.Milliseconds
 )
@@ -66,11 +67,17 @@ type connectorImp struct {
  started bool
 
  shutdownOnce sync.Once
+
+ // Event dimensions to add to the events metric.
+ eDimensions []dimension
+
+ events EventsConfig
 }
 
 type resourceMetrics struct {
  histograms metrics.HistogramMetrics
  sums metrics.SumMetrics
+ events metrics.SumMetrics
  attributes pcommon.Map
 }
 
@@ -113,6 +120,8 @@ func newConnector(logger *zap.Logger, config component.Config, ticker *clock.Tic
  metricKeyToDimensions: metricKeyToDimensionsCache,
  ticker: ticker,
  done: make(chan struct{}),
+ eDimensions: newDimensions(cfg.Events.Dimensions),
+ events: cfg.Events,
  }, nil
 }
 
@@ -245,6 +254,13 @@ func (p *connectorImp) buildMetrics() pmetric.Metrics {
  metric.SetUnit(p.config.Histogram.Unit.String())
  histograms.BuildMetrics(metric, p.startTimestamp, p.config.GetAggregationTemporality())
  }
+
+ events := rawMetrics.events
+ if p.events.Enabled {
+ metric = sm.Metrics().AppendEmpty()
+ metric.SetName(buildMetricName(p.config.Namespace, metricNameEvents))
+ events.BuildMetrics(metric, p.startTimestamp, p.config.GetAggregationTemporality())
+ }
  }
 
  return m
@@ -288,6 +304,7 @@ func (p *connectorImp) aggregateMetrics(traces ptrace.Traces) {
  rm := p.getOrCreateResourceMetrics(resourceAttr)
  sums := rm.sums
  histograms := rm.histograms
+ events := rm.events
 
  unitDivider := unitDivider(p.config.Histogram.Unit)
  serviceName := serviceAttr.Str()
@@ -308,7 +325,7 @@ func (p *connectorImp) aggregateMetrics(traces ptrace.Traces) {
 
  attributes, ok := p.metricKeyToDimensions.Get(key)
  if !ok {
- attributes = p.buildAttributes(serviceName, span, resourceAttr)
+ attributes = p.buildAttributes(serviceName, span, resourceAttr, p.dimensions)
  p.metricKeyToDimensions.Add(key, attributes)
  }
  if !p.config.Histogram.Disable {
@@ -321,6 +338,29 @@ func (p *connectorImp) aggregateMetrics(traces ptrace.Traces) {
  // aggregate sums metrics
  s := sums.GetOrCreate(key, attributes)
  s.Add(1)
+
+ // aggregate events metrics
+ if p.events.Enabled {
+ for l := 0; l < span.Events().Len(); l++ {
+ event := span.Events().At(l)
+ eDimensions := p.dimensions
+ eDimensions = append(eDimensions, p.eDimensions...)
+
+ rscAndEventAttrs := pcommon.NewMap()
+ rscAndEventAttrs.EnsureCapacity(resourceAttr.Len() + event.Attributes().Len())
+ resourceAttr.CopyTo(rscAndEventAttrs)
+ event.Attributes().CopyTo(rscAndEventAttrs)
+
+ eKey := p.buildKey(serviceName, span, eDimensions, rscAndEventAttrs)
+ eAttributes, ok := p.metricKeyToDimensions.Get(eKey)
+ if !ok {
+ eAttributes = p.buildAttributes(serviceName, span, rscAndEventAttrs, eDimensions)
+ p.metricKeyToDimensions.Add(eKey, eAttributes)
+ }
+ e := events.GetOrCreate(eKey, eAttributes)
+ e.Add(1)
+ }
+ }
  }
  }
  }
@@ -346,6 +386,7 @@ func (p *connectorImp) getOrCreateResourceMetrics(attr pcommon.Map) *resourceMet
  v = &resourceMetrics{
  histograms: initHistogramMetrics(p.config),
  sums: metrics.NewSumMetrics(),
+ events: metrics.NewSumMetrics(),
  attributes: attr,
  }
  p.resourceMetrics[key] = v
@@ -363,9 +404,9 @@ func contains(elements []string, value string) bool {
  return false
 }
 
-func (p *connectorImp) buildAttributes(serviceName string, span ptrace.Span, resourceAttrs pcommon.Map) pcommon.Map {
+func (p *connectorImp) buildAttributes(serviceName string, span ptrace.Span, resourceAttrs pcommon.Map, dimensions []dimension) pcommon.Map {
  attr := pcommon.NewMap()
- attr.EnsureCapacity(4 + len(p.dimensions))
+ attr.EnsureCapacity(4 + len(dimensions))
  if !contains(p.config.ExcludeDimensions, serviceNameKey) {
  attr.PutStr(serviceNameKey, serviceName)
  }
@@ -378,7 +419,7 @@ func (p *connectorImp) buildAttributes(serviceName string, span ptrace.Span, res
  if !contains(p.config.ExcludeDimensions, statusCodeKey) {
  attr.PutStr(statusCodeKey, traceutil.StatusCodeStr(span.Status().Code()))
  }
- for _, d := range p.dimensions {
+ for _, d := range dimensions {
  if v, ok := getDimensionValue(d, span.Attributes(), resourceAttrs); ok {
  v.CopyTo(attr.PutEmpty(d.name))
  }
@@ -395,10 +436,10 @@ func concatDimensionValue(dest *bytes.Buffer, value string, prefixSep bool) {
 
 // buildKey builds the metric key from the service name and span metadata such as name, kind, status_code and
 // will attempt to add any additional dimensions the user has configured that match the span's attributes
-// or resource attributes. If the dimension exists in both, the span's attributes, being the most specific, takes precedence.
+// or resource/event attributes. If the dimension exists in both, the span's attributes, being the most specific, takes precedence.
 //
 // The metric key is a simple concatenation of dimension values, delimited by a null character.
-func (p *connectorImp) buildKey(serviceName string, span ptrace.Span, optionalDims []dimension, resourceAttrs pcommon.Map) metrics.Key {
+func (p *connectorImp) buildKey(serviceName string, span ptrace.Span, optionalDims []dimension, resourceOrEventAttrs pcommon.Map) metrics.Key {
  p.keyBuf.Reset()
  if !contains(p.config.ExcludeDimensions, serviceNameKey) {
  concatDimensionValue(p.keyBuf, serviceName, false)
@@ -414,7 +455,7 @@ func (p *connectorImp) buildKey(serviceName string, span ptrace.Span, optionalDi
  }
 
  for _, d := range optionalDims {
- if v, ok := getDimensionValue(d, span.Attributes(), resourceAttrs); ok {
+ if v, ok := getDimensionValue(d, span.Attributes(), resourceOrEventAttrs); ok {
  concatDimensionValue(p.keyBuf, v.AsString(), true)
  }
  }

connector/spanmetricsconnector/connector_test.go

@@ -42,6 +42,7 @@ const (
  notInSpanAttrName0 = "shouldBeInMetric"
  notInSpanAttrName1 = "shouldNotBeInMetric"
  regionResourceAttrName = "region"
+ exceptionTypeAttrName = "exception.type"
  DimensionsCacheSize = 2
 
  sampleRegion = "us-east-1"
@@ -394,6 +395,10 @@ func initSpan(span span, s ptrace.Span) {
  s.Attributes().PutEmptySlice(arrayAttrName)
  s.SetTraceID(pcommon.TraceID(span.traceID))
  s.SetSpanID(pcommon.SpanID(span.spanID))
+
+ e := s.Events().AppendEmpty()
+ e.SetName("exception")
+ e.Attributes().PutStr(exceptionTypeAttrName, "NullPointerException")
 }
 
 func disabledExemplarsConfig() ExemplarsConfig {
@@ -1259,3 +1264,57 @@ func TestConnector_initHistogramMetrics(t *testing.T) {
  })
  }
 }
+
+func TestSpanMetrics_Events(t *testing.T) {
+ tests := []struct {
+ name string
+ eventsConfig EventsConfig
+ shouldEventsMetricExist bool
+ }{
+ {
+ name: "events disabled",
+ eventsConfig: EventsConfig{Enabled: false, Dimensions: []Dimension{{Name: "exception.type", Default: stringp("NullPointerException")}}},
+ shouldEventsMetricExist: false,
+ },
+ {
+ name: "events enabled",
+ eventsConfig: EventsConfig{Enabled: true, Dimensions: []Dimension{{Name: "exception.type", Default: stringp("NullPointerException")}}},
+ shouldEventsMetricExist: true,
+ },
+ }
+ for _, tt := range tests {
+ t.Run(tt.name, func(t *testing.T) {
+ factory := NewFactory()
+ cfg := factory.CreateDefaultConfig().(*Config)
+ cfg.Events = tt.eventsConfig
+ c, err := newConnector(zaptest.NewLogger(t), cfg, nil)
+ require.NoError(t, err)
+ err = c.ConsumeTraces(context.Background(), buildSampleTrace())
+ require.NoError(t, err)
+ metrics := c.buildMetrics()
+ for i := 0; i < metrics.ResourceMetrics().Len(); i++ {
+ rm := metrics.ResourceMetrics().At(i)
+ ism := rm.ScopeMetrics()
+ for ilmC := 0; ilmC < ism.Len(); ilmC++ {
+ m := ism.At(ilmC).Metrics()
+ if !tt.shouldEventsMetricExist {
+ assert.Equal(t, 2, m.Len())
+ continue
+ }
+ assert.Equal(t, 3, m.Len())
+ for mC := 0; mC < m.Len(); mC++ {
+ metric := m.At(mC)
+ if metric.Name() != "events" {
+ continue
+ }
+ assert.Equal(t, pmetric.MetricTypeSum, metric.Type())
+ for idp := 0; idp < metric.Sum().DataPoints().Len(); idp++ {
+ attrs := metric.Sum().DataPoints().At(idp).Attributes()
+ assert.Contains(t, attrs.AsRaw(), exceptionTypeAttrName)
+ }
+ }
+ }
+ }
+ })
+ }
+}