[processor/cumulativetodelta] Add metric type filter (open-telemetry#34407)

**Description:** Add metric type filter for cumulativetodelta processor

**Link to tracking Issue:** open-telemetry#33673

**Testing:** Added unit tests

**Documentation:** Extended the readme of this component to describe
this new filter

---------

Signed-off-by: Florian Bacher <[email protected]>

Author: bacherfl

.chloggen/cumulative-to-delta-processor-metric-type-filter.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: cumulativetodeltaprocessor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add metric type filter for cumulativetodelta processor
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33673]
+
+# (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: []

processor/cumulativetodeltaprocessor/README.md

@@ -23,8 +23,8 @@ Configuration is specified through a list of metrics. The processor uses metric
 
 The following settings can be optionally configured:
 
-- `include`: List of metrics names or patterns to convert to delta.
-- `exclude`: List of metrics names or patterns to not convert to delta.  **If a metric name matches both include and exclude, exclude takes precedence.**
+- `include`: List of metrics names (case-insensitive), patterns or metric types to convert to delta. Valid values are: `sum`, `histogram`.
+- `exclude`: List of metrics names (case-insensitive), patterns or metric types to not convert to delta.  **If a metric name matches both include and exclude, exclude takes precedence.** Valid values are: `sum`, `histogram`.
 - `max_staleness`: The total time a state entry will live past the time it was last seen. Set to 0 to retain state indefinitely. Default: 0
 - `initial_value`: Handling of the first observed point for a given metric identity.
   When the collector (re)starts, there's no record of how much of a given cumulative counter has already been converted to delta values.
@@ -56,6 +56,17 @@ processors:
             match_type: strict
 ```
 
+```yaml
+processors:
+    # processor name: cumulativetodelta
+    cumulativetodelta:
+
+        # Convert all sum metrics
+        include:
+            metric_types:
+              - sum
+```
+
 ```yaml
 processors:
     # processor name: cumulativetodelta
@@ -69,6 +80,21 @@ processors:
             match_type: regexp
 ```
 
+```yaml
+processors:
+    # processor name: cumulativetodelta
+    cumulativetodelta:
+
+        # Convert cumulative sum metrics to delta
+        # if and only if 'metric' is in the name
+        include:
+            metrics:
+                - ".*metric.*"
+            match_type: regexp
+            metric_types:
+              - sum
+```
+
 ```yaml
 processors:
     # processor name: cumulativetodelta
@@ -82,6 +108,22 @@ processors:
             match_type: regexp
 ```
 
+```yaml
+processors:
+    # processor name: cumulativetodelta
+    cumulativetodelta:
+
+        # Convert cumulative sum metrics with 'metric' in their name,
+        # but exclude histogram metrics
+        include:
+            metrics:
+                - ".*metric.*"
+            match_type: regexp
+        exclude:
+          metric_types:
+            - histogram
+```
+
 ```yaml
 processors:
     # processor name: cumulativetodelta

processor/cumulativetodeltaprocessor/config.go

@@ -5,14 +5,24 @@ package cumulativetodeltaprocessor // import "github.com/open-telemetry/opentele
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/pdata/pmetric"
+	"golang.org/x/exp/maps"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/filter/filterset"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/cumulativetodeltaprocessor/internal/tracking"
 )
 
+var validMetricTypes = map[string]bool{
+	strings.ToLower(pmetric.MetricTypeSum.String()):       true,
+	strings.ToLower(pmetric.MetricTypeHistogram.String()): true,
+}
+
+var validMetricTypeList = maps.Keys(validMetricTypes)
+
 // Config defines the configuration for the processor.
 type Config struct {
 	// MaxStaleness is the total time a state entry will live past the time it was last seen. Set to 0 to retain state indefinitely.
@@ -37,6 +47,8 @@ type MatchMetrics struct {
 	filterset.Config `mapstructure:",squash"`
 
 	Metrics []string `mapstructure:"metrics"`
+
+	MetricTypes []string `mapstructure:"metric_types"`
 }
 
 var _ component.Config = (*Config)(nil)
@@ -52,5 +64,24 @@ func (config *Config) Validate() error {
 		(len(config.Exclude.MatchType) > 0 && len(config.Exclude.Metrics) == 0) {
 		return fmt.Errorf("metrics must be supplied if match_type is set")
 	}
+
+	for _, metricType := range config.Exclude.MetricTypes {
+		if valid := validMetricTypes[strings.ToLower(metricType)]; !valid {
+			return fmt.Errorf(
+				"found invalid metric type in exclude.metric_types: %s. Valid values are %s",
+				metricType,
+				validMetricTypeList,
+			)
+		}
+	}
+	for _, metricType := range config.Include.MetricTypes {
+		if valid := validMetricTypes[strings.ToLower(metricType)]; !valid {
+			return fmt.Errorf(
+				"found invalid metric type in include.metric_types: %s. Valid values are %s",
+				metricType,
+				validMetricTypeList,
+			)
+		}
+	}
 	return nil
 }

processor/cumulativetodeltaprocessor/config_test.go

@@ -4,6 +4,7 @@
 package cumulativetodeltaprocessor
 
 import (
+	"fmt"
 	"path/filepath"
 	"testing"
 	"time"
@@ -82,6 +83,45 @@ func TestLoadConfig(t *testing.T) {
 				InitialValue: tracking.InitialValueAuto,
 			},
 		},
+		{
+			id: component.NewIDWithName(metadata.Type, "metric_type_filter"),
+			expected: &Config{
+				Include: MatchMetrics{
+					Metrics: []string{
+						"a*",
+					},
+					Config: filterset.Config{
+						MatchType:    "regexp",
+						RegexpConfig: nil,
+					},
+					MetricTypes: []string{
+						"sum",
+					},
+				},
+				Exclude: MatchMetrics{
+					Metrics: []string{
+						"b*",
+					},
+					Config: filterset.Config{
+						MatchType:    "regexp",
+						RegexpConfig: nil,
+					},
+					MetricTypes: []string{
+						"histogram",
+					},
+				},
+				MaxStaleness: 10 * time.Second,
+				InitialValue: tracking.InitialValueAuto,
+			},
+		},
+		{
+			id:           component.NewIDWithName(metadata.Type, "invalid_include_metric_type_filter"),
+			errorMessage: fmt.Sprintf("found invalid metric type in include.metric_types: gauge. Valid values are %s", validMetricTypeList),
+		},
+		{
+			id:           component.NewIDWithName(metadata.Type, "invalid_exclude_metric_type_filter"),
+			errorMessage: fmt.Sprintf("found invalid metric type in exclude.metric_types: Invalid. Valid values are %s", validMetricTypeList),
+		},
 		{
 			id:           component.NewIDWithName(metadata.Type, "missing_match_type"),
 			errorMessage: "match_type must be set if metrics are supplied",

processor/cumulativetodeltaprocessor/factory.go

@@ -40,7 +40,10 @@ func createMetricsProcessor(
 		return nil, fmt.Errorf("configuration parsing error")
 	}
 
-	metricsProcessor := newCumulativeToDeltaProcessor(processorConfig, set.Logger)
+	metricsProcessor, err := newCumulativeToDeltaProcessor(processorConfig, set.Logger)
+	if err != nil {
+		return nil, err
+	}
 
 	return processorhelper.NewMetrics(
 		ctx,

processor/cumulativetodeltaprocessor/factory_test.go

@@ -6,6 +6,7 @@ package cumulativetodeltaprocessor
 import (
 	"context"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -61,6 +62,12 @@ func TestCreateProcessors(t *testing.T) {
 				processortest.NewNopSettings(),
 				cfg,
 				consumertest.NewNop())
+
+			if strings.Contains(k, "invalid") {
+				assert.Error(t, mErr)
+				assert.Nil(t, mp)
+				return
+			}
 			assert.NotNil(t, mp)
 			assert.NoError(t, mErr)
 			assert.NoError(t, mp.Shutdown(context.Background()))

processor/cumulativetodeltaprocessor/go.mod

@@ -16,6 +16,7 @@ require (
 	go.opentelemetry.io/collector/processor/processortest v0.118.1-0.20250121185328-fbefb22cc2b3
 	go.uber.org/goleak v1.3.0
 	go.uber.org/zap v1.27.0
+	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842
 )
 
 require (

processor/cumulativetodeltaprocessor/go.sum

@@ -5,7 +5,9 @@ package cumulativetodeltaprocessor // import "github.com/open-telemetry/opentele
 
 import (
 	"context"
+	"fmt"
 	"math"
+	"strings"
 
 	"go.opentelemetry.io/collector/pdata/pmetric"
 	"go.uber.org/zap"
@@ -15,35 +17,71 @@ import (
 )
 
 type cumulativeToDeltaProcessor struct {
-	includeFS       filterset.FilterSet
-	excludeFS       filterset.FilterSet
-	logger          *zap.Logger
-	deltaCalculator *tracking.MetricTracker
-	cancelFunc      context.CancelFunc
+	includeFS          filterset.FilterSet
+	excludeFS          filterset.FilterSet
+	includeMetricTypes map[pmetric.MetricType]bool
+	excludeMetricTypes map[pmetric.MetricType]bool
+	logger             *zap.Logger
+	deltaCalculator    *tracking.MetricTracker
+	cancelFunc         context.CancelFunc
 }
 
-func newCumulativeToDeltaProcessor(config *Config, logger *zap.Logger) *cumulativeToDeltaProcessor {
+func newCumulativeToDeltaProcessor(config *Config, logger *zap.Logger) (*cumulativeToDeltaProcessor, error) {
 	ctx, cancel := context.WithCancel(context.Background())
+
 	p := &cumulativeToDeltaProcessor{
-		logger:          logger,
-		deltaCalculator: tracking.NewMetricTracker(ctx, logger, config.MaxStaleness, config.InitialValue),
-		cancelFunc:      cancel,
+		logger:     logger,
+		cancelFunc: cancel,
 	}
 	if len(config.Include.Metrics) > 0 {
 		p.includeFS, _ = filterset.CreateFilterSet(config.Include.Metrics, &config.Include.Config)
 	}
 	if len(config.Exclude.Metrics) > 0 {
 		p.excludeFS, _ = filterset.CreateFilterSet(config.Exclude.Metrics, &config.Exclude.Config)
 	}
-	return p
+
+	if len(config.Include.MetricTypes) > 0 {
+		includeMetricTypeFilter, err := getMetricTypeFilter(config.Include.MetricTypes)
+		if err != nil {
+			return nil, err
+		}
+		p.includeMetricTypes = includeMetricTypeFilter
+	}
+
+	if len(config.Exclude.MetricTypes) > 0 {
+		excludeMetricTypeFilter, err := getMetricTypeFilter(config.Exclude.MetricTypes)
+		if err != nil {
+			return nil, err
+		}
+		p.excludeMetricTypes = excludeMetricTypeFilter
+	}
+
+	p.deltaCalculator = tracking.NewMetricTracker(ctx, logger, config.MaxStaleness, config.InitialValue)
+
+	return p, nil
+}
+
+func getMetricTypeFilter(types []string) (map[pmetric.MetricType]bool, error) {
+	res := map[pmetric.MetricType]bool{}
+	for _, t := range types {
+		switch strings.ToLower(t) {
+		case strings.ToLower(pmetric.MetricTypeSum.String()):
+			res[pmetric.MetricTypeSum] = true
+		case strings.ToLower(pmetric.MetricTypeHistogram.String()):
+			res[pmetric.MetricTypeHistogram] = true
+		default:
+			return nil, fmt.Errorf("unsupported metric type filter: %s", t)
+		}
+	}
+	return res, nil
 }
 
 // processMetrics implements the ProcessMetricsFunc type.
 func (ctdp *cumulativeToDeltaProcessor) processMetrics(_ context.Context, md pmetric.Metrics) (pmetric.Metrics, error) {
 	md.ResourceMetrics().RemoveIf(func(rm pmetric.ResourceMetrics) bool {
 		rm.ScopeMetrics().RemoveIf(func(ilm pmetric.ScopeMetrics) bool {
 			ilm.Metrics().RemoveIf(func(m pmetric.Metric) bool {
-				if !ctdp.shouldConvertMetric(m.Name()) {
+				if !ctdp.shouldConvertMetric(m) {
 					return false
 				}
 				switch m.Type() {
@@ -111,9 +149,11 @@ func (ctdp *cumulativeToDeltaProcessor) shutdown(context.Context) error {
 	return nil
 }
 
-func (ctdp *cumulativeToDeltaProcessor) shouldConvertMetric(metricName string) bool {
-	return (ctdp.includeFS == nil || ctdp.includeFS.Matches(metricName)) &&
-		(ctdp.excludeFS == nil || !ctdp.excludeFS.Matches(metricName))
+func (ctdp *cumulativeToDeltaProcessor) shouldConvertMetric(metric pmetric.Metric) bool {
+	return (ctdp.includeFS == nil || ctdp.includeFS.Matches(metric.Name())) &&
+		(len(ctdp.includeMetricTypes) == 0 || ctdp.includeMetricTypes[metric.Type()]) &&
+		(ctdp.excludeFS == nil || !ctdp.excludeFS.Matches(metric.Name())) &&
+		(len(ctdp.excludeMetricTypes) == 0 || !ctdp.excludeMetricTypes[metric.Type()])
 }
 
 func (ctdp *cumulativeToDeltaProcessor) convertNumberDataPoints(dps pmetric.NumberDataPointSlice, baseIdentity tracking.MetricIdentity) {