[processor/tailsampling]: Enable inverse filtering for boolean attrib…

…ute filter (open-telemetry#34730)

**Description:** This PR adds the `invert_match` option for
`boolean_attribute` filters, as discussed in
open-telemetry#34296 (comment)

**Link to tracking Issue:** open-telemetry#34296

**Testing:** Added unit tests

**Documentation:** The existing documentation already covered the
semantics of the `invert_match` option

---------

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

.chloggen/tail_sampling_processor_inverted_bool_sampling.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: tailsamplingprocessor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix the behavior for numeric tag filters with `inverse_match` set to `true`.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34296]
+
+# (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/tailsamplingprocessor/README.md

@@ -58,7 +58,7 @@ Each policy will result in a decision, and the processor will evaluate them to m
 - When there's a "inverted sample" decision and no "not sample" decisions, the trace is sampled;
 - In all other cases, the trace is NOT sampled
 
-An "inverted" decision is the one made based on the "invert_match" attribute, such as the one from the string tag policy.
+An "inverted" decision is the one made based on the "invert_match" attribute, such as the one from the string, numeric or boolean tag policy.
 
 Examples:
 
@@ -223,6 +223,8 @@ Imagine that you wish to configure the processor to implement the following rule
 
 1. **Rule 6:** Add an escape hatch. If there is an attribute called `app.force_sample` in the span, then sample the trace at 100 percent.
 
+1. **Rule 7:** Force spans with `app.do_not_sample` set to `true` to not be sampled, even if the result of the other rules yield a sampling decision.
+
 Here is what the configuration would look like:
 
 ```yaml
@@ -407,6 +409,13 @@ tail_sampling:
         type: boolean_attribute,
         boolean_attribute: { key: app.force_sample, value: true },
       },
+    {
+      # Rule 7:
+      # never sample if the do_not_sample attribute is set to true
+      name: team_a-do-not-sample,
+      type: boolean_attribute,
+      boolean_attribute: { key: app.do_not_sample, value: true, invert_match: true },
+    },
       # END: policies for team_a
     ]
 ```

processor/tailsamplingprocessor/config.go

@@ -210,6 +210,10 @@ type BooleanAttributeCfg struct {
 	// Value indicate the bool value, either true or false to use when matching against attribute values.
 	// BooleanAttribute Policy will apply exact value match on Value
 	Value bool `mapstructure:"value"`
+	// InvertMatch indicates that values must not match against attribute values.
+	// If InvertMatch is true and Values is equal to 'true', all other values will be sampled except 'true'.
+	// Also, if the specified Key does not match any resource or span attributes, data will be sampled.
+	InvertMatch bool `mapstructure:"invert_match"`
 }
 
 // OTTLConditionCfg holds the configurable setting to create a OTTL condition filter

processor/tailsamplingprocessor/internal/sampling/boolean_tag_filter.go

@@ -13,20 +13,22 @@ import (
 )
 
 type booleanAttributeFilter struct {
-	key    string
-	value  bool
-	logger *zap.Logger
+	key         string
+	value       bool
+	logger      *zap.Logger
+	invertMatch bool
 }
 
 var _ PolicyEvaluator = (*booleanAttributeFilter)(nil)
 
 // NewBooleanAttributeFilter creates a policy evaluator that samples all traces with
 // the given attribute that match the supplied boolean value.
-func NewBooleanAttributeFilter(settings component.TelemetrySettings, key string, value bool) PolicyEvaluator {
+func NewBooleanAttributeFilter(settings component.TelemetrySettings, key string, value bool, invertMatch bool) PolicyEvaluator {
 	return &booleanAttributeFilter{
-		key:    key,
-		value:  value,
-		logger: settings.Logger,
+		key:         key,
+		value:       value,
+		logger:      settings.Logger,
+		invertMatch: invertMatch,
 	}
 }
 
@@ -36,6 +38,25 @@ func (baf *booleanAttributeFilter) Evaluate(_ context.Context, _ pcommon.TraceID
 	defer trace.Unlock()
 	batches := trace.ReceivedBatches
 
+	if baf.invertMatch {
+		return invertHasResourceOrSpanWithCondition(
+			batches,
+			func(resource pcommon.Resource) bool {
+				if v, ok := resource.Attributes().Get(baf.key); ok {
+					value := v.Bool()
+					return value != baf.value
+				}
+				return true
+			},
+			func(span ptrace.Span) bool {
+				if v, ok := span.Attributes().Get(baf.key); ok {
+					value := v.Bool()
+					return value != baf.value
+				}
+				return true
+			},
+		), nil
+	}
 	return hasResourceOrSpanWithCondition(
 		batches,
 		func(resource pcommon.Resource) bool {

processor/tailsamplingprocessor/internal/sampling/boolean_tag_filter_test.go

@@ -17,7 +17,7 @@ import (
 func TestBooleanTagFilter(t *testing.T) {
 
 	var empty = map[string]any{}
-	filter := NewBooleanAttributeFilter(componenttest.NewNopTelemetrySettings(), "example", true)
+	filter := NewBooleanAttributeFilter(componenttest.NewNopTelemetrySettings(), "example", true, false)
 
 	resAttr := map[string]any{}
 	resAttr["example"] = 8
@@ -54,6 +54,46 @@ func TestBooleanTagFilter(t *testing.T) {
 	}
 }
 
+func TestBooleanTagFilterInverted(t *testing.T) {
+
+	var empty = map[string]any{}
+	filter := NewBooleanAttributeFilter(componenttest.NewNopTelemetrySettings(), "example", true, true)
+
+	resAttr := map[string]any{}
+	resAttr["example"] = 8
+
+	cases := []struct {
+		Desc     string
+		Trace    *TraceData
+		Decision Decision
+	}{
+		{
+			Desc:     "non-matching span attribute",
+			Trace:    newTraceBoolAttrs(empty, "non_matching", true),
+			Decision: InvertSampled,
+		},
+		{
+			Desc:     "span attribute with non matching boolean value",
+			Trace:    newTraceBoolAttrs(empty, "example", false),
+			Decision: InvertSampled,
+		},
+		{
+			Desc:     "span attribute with matching boolean value",
+			Trace:    newTraceBoolAttrs(empty, "example", true),
+			Decision: InvertNotSampled,
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.Desc, func(t *testing.T) {
+			u, _ := uuid.NewRandom()
+			decision, err := filter.Evaluate(context.Background(), pcommon.TraceID(u), c.Trace)
+			assert.NoError(t, err)
+			assert.Equal(t, decision, c.Decision)
+		})
+	}
+}
+
 func newTraceBoolAttrs(nodeAttrs map[string]any, spanAttrKey string, spanAttrValue bool) *TraceData {
 	traces := ptrace.NewTraces()
 	rs := traces.ResourceSpans().AppendEmpty()

processor/tailsamplingprocessor/processor.go

@@ -231,7 +231,7 @@ func getSharedPolicyEvaluator(settings component.TelemetrySettings, cfg *sharedP
 		return sampling.NewTraceStateFilter(settings, tsfCfg.Key, tsfCfg.Values), nil
 	case BooleanAttribute:
 		bafCfg := cfg.BooleanAttributeCfg
-		return sampling.NewBooleanAttributeFilter(settings, bafCfg.Key, bafCfg.Value), nil
+		return sampling.NewBooleanAttributeFilter(settings, bafCfg.Key, bafCfg.Value, bafCfg.InvertMatch), nil
 	case OTTLCondition:
 		ottlfCfg := cfg.OTTLConditionCfg
 		return sampling.NewOTTLConditionFilter(settings, ottlfCfg.SpanConditions, ottlfCfg.SpanEventConditions, ottlfCfg.ErrorMode)