[tailsamplingprocessor] Support external decision cache implementations

.chloggen/tsp-external-cache.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: Add support for external caches when using the Tailsampling Processor in code.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [37035]
+
+# (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: [api]

processor/tailsamplingprocessor/internal/cache/lru_cache.go → processor/tailsamplingprocessor/cache/lru_cache.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package cache // import "github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/cache"
+package cache // import "github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/cache"
 
 import (
 	"encoding/binary"

processor/tailsamplingprocessor/internal/cache/nop_cache.go → processor/tailsamplingprocessor/cache/nop_cache.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package cache // import "github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/cache"
+package cache // import "github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/cache"
 
 import "go.opentelemetry.io/collector/pdata/pcommon"
 

processor/tailsamplingprocessor/internal/cache/types.go → processor/tailsamplingprocessor/cache/types.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package cache // import "github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/cache"
+package cache // import "github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/cache"
 
 import "go.opentelemetry.io/collector/pdata/pcommon"
 

processor/tailsamplingprocessor/config.go

@@ -253,4 +253,6 @@ type Config struct {
 	PolicyCfgs []PolicyCfg `mapstructure:"policies"`
 	// DecisionCache holds configuration for the decision cache(s)
 	DecisionCache DecisionCacheConfig `mapstructure:"decision_cache"`
+	// Options allows for additional configuration of the tail-based sampling processor in code.
+	Options []Option `mapstructure:"-"`
 }

processor/tailsamplingprocessor/processor.go

@@ -22,7 +22,7 @@ import (
 	"go.uber.org/zap"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal/timeutils"
-	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/cache"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/cache"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/idbatcher"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/metadata"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/sampling"
@@ -88,7 +88,7 @@ type Option func(*tailSamplingSpanProcessor)
 
 // newTracesProcessor returns a processor.TracesProcessor that will perform tail sampling according to the given
 // configuration.
-func newTracesProcessor(ctx context.Context, set processor.Settings, nextConsumer consumer.Traces, cfg Config, opts ...Option) (processor.Traces, error) {
+func newTracesProcessor(ctx context.Context, set processor.Settings, nextConsumer consumer.Traces, cfg Config) (processor.Traces, error) {
 	telemetrySettings := set.TelemetrySettings
 	telemetry, err := metadata.NewTelemetryBuilder(telemetrySettings)
 	if err != nil {
@@ -124,7 +124,7 @@ func newTracesProcessor(ctx context.Context, set processor.Settings, nextConsume
 	}
 	tsp.policyTicker = &timeutils.PolicyTicker{OnTickFunc: tsp.samplingPolicyOnTick}
 
-	for _, opt := range opts {
+	for _, opt := range cfg.Options {
 		opt(tsp)
 	}
 
@@ -174,15 +174,15 @@ func withTickerFrequency(frequency time.Duration) Option {
 	}
 }
 
-// withSampledDecisionCache sets the cache which the processor uses to store recently sampled trace IDs.
-func withSampledDecisionCache(c cache.Cache[bool]) Option {
+// WithSampledDecisionCache sets the cache which the processor uses to store recently sampled trace IDs.
+func WithSampledDecisionCache(c cache.Cache[bool]) Option {
 	return func(tsp *tailSamplingSpanProcessor) {
 		tsp.sampledIDCache = c
 	}
 }
 
-// withSampledDecisionCache sets the cache which the processor uses to store recently sampled trace IDs.
-func withNonSampledDecisionCache(c cache.Cache[bool]) Option {
+// WithNonSampledDecisionCache sets the cache which the processor uses to store recently non-sampled trace IDs.
+func WithNonSampledDecisionCache(c cache.Cache[bool]) Option {
 	return func(tsp *tailSamplingSpanProcessor) {
 		tsp.nonSampledIDCache = c
 	}

processor/tailsamplingprocessor/processor_decisions_test.go

@@ -14,16 +14,12 @@ import (
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
 
-	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/cache"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/cache"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/metadatatest"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor/internal/sampling"
 )
 
 func TestSamplingPolicyTypicalPath(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	tel := metadatatest.SetupTelemetry()
 	idb := newSyncIDBatcher()
@@ -34,7 +30,15 @@ func TestSamplingPolicyTypicalPath(t *testing.T) {
 		{name: "mock-policy-1", evaluator: mpe1, attribute: metric.WithAttributes(attribute.String("policy", "mock-policy-1"))},
 	}
 
-	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies))
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))
@@ -65,10 +69,6 @@ func TestSamplingPolicyTypicalPath(t *testing.T) {
 }
 
 func TestSamplingPolicyInvertSampled(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	tel := metadatatest.SetupTelemetry()
 	idb := newSyncIDBatcher()
@@ -79,7 +79,15 @@ func TestSamplingPolicyInvertSampled(t *testing.T) {
 		{name: "mock-policy-1", evaluator: mpe1, attribute: metric.WithAttributes(attribute.String("policy", "mock-policy-1"))},
 	}
 
-	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies))
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))
@@ -110,10 +118,6 @@ func TestSamplingPolicyInvertSampled(t *testing.T) {
 }
 
 func TestSamplingMultiplePolicies(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	tel := metadatatest.SetupTelemetry()
 	idb := newSyncIDBatcher()
@@ -126,7 +130,15 @@ func TestSamplingMultiplePolicies(t *testing.T) {
 		{name: "mock-policy-2", evaluator: mpe2, attribute: metric.WithAttributes(attribute.String("policy", "mock-policy-2"))},
 	}
 
-	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies))
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))
@@ -161,10 +173,6 @@ func TestSamplingMultiplePolicies(t *testing.T) {
 }
 
 func TestSamplingPolicyDecisionNotSampled(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	tel := metadatatest.SetupTelemetry()
 	idb := newSyncIDBatcher()
@@ -175,7 +183,15 @@ func TestSamplingPolicyDecisionNotSampled(t *testing.T) {
 		{name: "mock-policy-1", evaluator: mpe1, attribute: metric.WithAttributes(attribute.String("policy", "mock-policy-1"))},
 	}
 
-	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies))
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))
@@ -207,10 +223,6 @@ func TestSamplingPolicyDecisionNotSampled(t *testing.T) {
 }
 
 func TestSamplingPolicyDecisionInvertNotSampled(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	tel := metadatatest.SetupTelemetry()
 	idb := newSyncIDBatcher()
@@ -223,7 +235,15 @@ func TestSamplingPolicyDecisionInvertNotSampled(t *testing.T) {
 		{name: "mock-policy-2", evaluator: mpe2, attribute: metric.WithAttributes(attribute.String("policy", "mock-policy-2"))},
 	}
 
-	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies))
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))
@@ -258,10 +278,6 @@ func TestSamplingPolicyDecisionInvertNotSampled(t *testing.T) {
 }
 
 func TestLateArrivingSpansAssignedOriginalDecision(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	tel := metadatatest.SetupTelemetry()
 	idb := newSyncIDBatcher()
@@ -274,7 +290,15 @@ func TestLateArrivingSpansAssignedOriginalDecision(t *testing.T) {
 		{name: "mock-policy-2", evaluator: mpe2, attribute: metric.WithAttributes(attribute.String("policy", "mock-policy-2"))},
 	}
 
-	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies))
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))
@@ -328,10 +352,6 @@ func TestLateArrivingSpansAssignedOriginalDecision(t *testing.T) {
 }
 
 func TestLateArrivingSpanUsesDecisionCache(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait * 10,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	tel := metadatatest.SetupTelemetry()
 	idb := newSyncIDBatcher()
@@ -344,7 +364,17 @@ func TestLateArrivingSpanUsesDecisionCache(t *testing.T) {
 	// Use this instead of the default no-op cache
 	c, err := cache.NewLRUDecisionCache[bool](200)
 	require.NoError(t, err)
-	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies), withSampledDecisionCache(c))
+
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait * 10,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+			WithSampledDecisionCache(c),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), tel.NewSettings(), nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))
@@ -401,10 +431,6 @@ func TestLateArrivingSpanUsesDecisionCache(t *testing.T) {
 }
 
 func TestLateSpanUsesNonSampledDecisionCache(t *testing.T) {
-	cfg := Config{
-		DecisionWait: defaultTestDecisionWait * 10,
-		NumTraces:    defaultNumTraces,
-	}
 	nextConsumer := new(consumertest.TracesSink)
 	s := metadatatest.SetupTelemetry()
 	ct := s.NewSettings()
@@ -418,7 +444,17 @@ func TestLateSpanUsesNonSampledDecisionCache(t *testing.T) {
 	// Use this instead of the default no-op cache
 	c, err := cache.NewLRUDecisionCache[bool](200)
 	require.NoError(t, err)
-	p, err := newTracesProcessor(context.Background(), ct, nextConsumer, cfg, withDecisionBatcher(idb), withPolicies(policies), withNonSampledDecisionCache(c))
+
+	cfg := Config{
+		DecisionWait: defaultTestDecisionWait * 10,
+		NumTraces:    defaultNumTraces,
+		Options: []Option{
+			withDecisionBatcher(idb),
+			withPolicies(policies),
+			WithNonSampledDecisionCache(c),
+		},
+	}
+	p, err := newTracesProcessor(context.Background(), ct, nextConsumer, cfg)
 	require.NoError(t, err)
 
 	require.NoError(t, p.Start(context.Background(), componenttest.NewNopHost()))