build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/README.md

@@ -0,0 +1,3 @@
+# SDK Trace
+
+[![PkgGoDev](https://pkg.go.dev/badge/go.opentelemetry.io/otel/sdk/trace)](https://pkg.go.dev/go.opentelemetry.io/otel/sdk/trace)

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/batch_span_processor.go

@@ -0,0 +1,414 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/internal/global"
+	"go.opentelemetry.io/otel/sdk/internal/env"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// Defaults for BatchSpanProcessorOptions.
+const (
+	DefaultMaxQueueSize       = 2048
+	DefaultScheduleDelay      = 5000
+	DefaultExportTimeout      = 30000
+	DefaultMaxExportBatchSize = 512
+)
+
+// BatchSpanProcessorOption configures a BatchSpanProcessor.
+type BatchSpanProcessorOption func(o *BatchSpanProcessorOptions)
+
+// BatchSpanProcessorOptions is configuration settings for a
+// BatchSpanProcessor.
+type BatchSpanProcessorOptions struct {
+	// MaxQueueSize is the maximum queue size to buffer spans for delayed processing. If the
+	// queue gets full it drops the spans. Use BlockOnQueueFull to change this behavior.
+	// The default value of MaxQueueSize is 2048.
+	MaxQueueSize int
+
+	// BatchTimeout is the maximum duration for constructing a batch. Processor
+	// forcefully sends available spans when timeout is reached.
+	// The default value of BatchTimeout is 5000 msec.
+	BatchTimeout time.Duration
+
+	// ExportTimeout specifies the maximum duration for exporting spans. If the timeout
+	// is reached, the export will be cancelled.
+	// The default value of ExportTimeout is 30000 msec.
+	ExportTimeout time.Duration
+
+	// MaxExportBatchSize is the maximum number of spans to process in a single batch.
+	// If there are more than one batch worth of spans then it processes multiple batches
+	// of spans one batch after the other without any delay.
+	// The default value of MaxExportBatchSize is 512.
+	MaxExportBatchSize int
+
+	// BlockOnQueueFull blocks onEnd() and onStart() method if the queue is full
+	// AND if BlockOnQueueFull is set to true.
+	// Blocking option should be used carefully as it can severely affect the performance of an
+	// application.
+	BlockOnQueueFull bool
+}
+
+// batchSpanProcessor is a SpanProcessor that batches asynchronously-received
+// spans and sends them to a trace.Exporter when complete.
+type batchSpanProcessor struct {
+	e SpanExporter
+	o BatchSpanProcessorOptions
+
+	queue   chan ReadOnlySpan
+	dropped uint32
+
+	batch      []ReadOnlySpan
+	batchMutex sync.Mutex
+	timer      *time.Timer
+	stopWait   sync.WaitGroup
+	stopOnce   sync.Once
+	stopCh     chan struct{}
+	stopped    atomic.Bool
+}
+
+var _ SpanProcessor = (*batchSpanProcessor)(nil)
+
+// NewBatchSpanProcessor creates a new SpanProcessor that will send completed
+// span batches to the exporter with the supplied options.
+//
+// If the exporter is nil, the span processor will perform no action.
+func NewBatchSpanProcessor(exporter SpanExporter, options ...BatchSpanProcessorOption) SpanProcessor {
+	maxQueueSize := env.BatchSpanProcessorMaxQueueSize(DefaultMaxQueueSize)
+	maxExportBatchSize := env.BatchSpanProcessorMaxExportBatchSize(DefaultMaxExportBatchSize)
+
+	if maxExportBatchSize > maxQueueSize {
+		if DefaultMaxExportBatchSize > maxQueueSize {
+			maxExportBatchSize = maxQueueSize
+		} else {
+			maxExportBatchSize = DefaultMaxExportBatchSize
+		}
+	}
+
+	o := BatchSpanProcessorOptions{
+		BatchTimeout:       time.Duration(env.BatchSpanProcessorScheduleDelay(DefaultScheduleDelay)) * time.Millisecond,
+		ExportTimeout:      time.Duration(env.BatchSpanProcessorExportTimeout(DefaultExportTimeout)) * time.Millisecond,
+		MaxQueueSize:       maxQueueSize,
+		MaxExportBatchSize: maxExportBatchSize,
+	}
+	for _, opt := range options {
+		opt(&o)
+	}
+	bsp := &batchSpanProcessor{
+		e:      exporter,
+		o:      o,
+		batch:  make([]ReadOnlySpan, 0, o.MaxExportBatchSize),
+		timer:  time.NewTimer(o.BatchTimeout),
+		queue:  make(chan ReadOnlySpan, o.MaxQueueSize),
+		stopCh: make(chan struct{}),
+	}
+
+	bsp.stopWait.Add(1)
+	go func() {
+		defer bsp.stopWait.Done()
+		bsp.processQueue()
+		bsp.drainQueue()
+	}()
+
+	return bsp
+}
+
+// OnStart method does nothing.
+func (bsp *batchSpanProcessor) OnStart(parent context.Context, s ReadWriteSpan) {}
+
+// OnEnd method enqueues a ReadOnlySpan for later processing.
+func (bsp *batchSpanProcessor) OnEnd(s ReadOnlySpan) {
+	// Do not enqueue spans after Shutdown.
+	if bsp.stopped.Load() {
+		return
+	}
+
+	// Do not enqueue spans if we are just going to drop them.
+	if bsp.e == nil {
+		return
+	}
+	bsp.enqueue(s)
+}
+
+// Shutdown flushes the queue and waits until all spans are processed.
+// It only executes once. Subsequent call does nothing.
+func (bsp *batchSpanProcessor) Shutdown(ctx context.Context) error {
+	var err error
+	bsp.stopOnce.Do(func() {
+		bsp.stopped.Store(true)
+		wait := make(chan struct{})
+		go func() {
+			close(bsp.stopCh)
+			bsp.stopWait.Wait()
+			if bsp.e != nil {
+				if err := bsp.e.Shutdown(ctx); err != nil {
+					otel.Handle(err)
+				}
+			}
+			close(wait)
+		}()
+		// Wait until the wait group is done or the context is cancelled
+		select {
+		case <-wait:
+		case <-ctx.Done():
+			err = ctx.Err()
+		}
+	})
+	return err
+}
+
+type forceFlushSpan struct {
+	ReadOnlySpan
+	flushed chan struct{}
+}
+
+func (f forceFlushSpan) SpanContext() trace.SpanContext {
+	return trace.NewSpanContext(trace.SpanContextConfig{TraceFlags: trace.FlagsSampled})
+}
+
+// ForceFlush exports all ended spans that have not yet been exported.
+func (bsp *batchSpanProcessor) ForceFlush(ctx context.Context) error {
+	// Interrupt if context is already canceled.
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	// Do nothing after Shutdown.
+	if bsp.stopped.Load() {
+		return nil
+	}
+
+	var err error
+	if bsp.e != nil {
+		flushCh := make(chan struct{})
+		if bsp.enqueueBlockOnQueueFull(ctx, forceFlushSpan{flushed: flushCh}) {
+			select {
+			case <-bsp.stopCh:
+				// The batchSpanProcessor is Shutdown.
+				return nil
+			case <-flushCh:
+				// Processed any items in queue prior to ForceFlush being called
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+		}
+
+		wait := make(chan error)
+		go func() {
+			wait <- bsp.exportSpans(ctx)
+			close(wait)
+		}()
+		// Wait until the export is finished or the context is cancelled/timed out
+		select {
+		case err = <-wait:
+		case <-ctx.Done():
+			err = ctx.Err()
+		}
+	}
+	return err
+}
+
+// WithMaxQueueSize returns a BatchSpanProcessorOption that configures the
+// maximum queue size allowed for a BatchSpanProcessor.
+func WithMaxQueueSize(size int) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.MaxQueueSize = size
+	}
+}
+
+// WithMaxExportBatchSize returns a BatchSpanProcessorOption that configures
+// the maximum export batch size allowed for a BatchSpanProcessor.
+func WithMaxExportBatchSize(size int) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.MaxExportBatchSize = size
+	}
+}
+
+// WithBatchTimeout returns a BatchSpanProcessorOption that configures the
+// maximum delay allowed for a BatchSpanProcessor before it will export any
+// held span (whether the queue is full or not).
+func WithBatchTimeout(delay time.Duration) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.BatchTimeout = delay
+	}
+}
+
+// WithExportTimeout returns a BatchSpanProcessorOption that configures the
+// amount of time a BatchSpanProcessor waits for an exporter to export before
+// abandoning the export.
+func WithExportTimeout(timeout time.Duration) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.ExportTimeout = timeout
+	}
+}
+
+// WithBlocking returns a BatchSpanProcessorOption that configures a
+// BatchSpanProcessor to wait for enqueue operations to succeed instead of
+// dropping data when the queue is full.
+func WithBlocking() BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.BlockOnQueueFull = true
+	}
+}
+
+// exportSpans is a subroutine of processing and draining the queue.
+func (bsp *batchSpanProcessor) exportSpans(ctx context.Context) error {
+	bsp.timer.Reset(bsp.o.BatchTimeout)
+
+	bsp.batchMutex.Lock()
+	defer bsp.batchMutex.Unlock()
+
+	if bsp.o.ExportTimeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, bsp.o.ExportTimeout)
+		defer cancel()
+	}
+
+	if l := len(bsp.batch); l > 0 {
+		global.Debug("exporting spans", "count", len(bsp.batch), "total_dropped", atomic.LoadUint32(&bsp.dropped))
+		err := bsp.e.ExportSpans(ctx, bsp.batch)
+
+		// A new batch is always created after exporting, even if the batch failed to be exported.
+		//
+		// It is up to the exporter to implement any type of retry logic if a batch is failing
+		// to be exported, since it is specific to the protocol and backend being sent to.
+		clear(bsp.batch) // Erase elements to let GC collect objects
+		bsp.batch = bsp.batch[:0]
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// processQueue removes spans from the `queue` channel until processor
+// is shut down. It calls the exporter in batches of up to MaxExportBatchSize
+// waiting up to BatchTimeout to form a batch.
+func (bsp *batchSpanProcessor) processQueue() {
+	defer bsp.timer.Stop()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	for {
+		select {
+		case <-bsp.stopCh:
+			return
+		case <-bsp.timer.C:
+			if err := bsp.exportSpans(ctx); err != nil {
+				otel.Handle(err)
+			}
+		case sd := <-bsp.queue:
+			if ffs, ok := sd.(forceFlushSpan); ok {
+				close(ffs.flushed)
+				continue
+			}
+			bsp.batchMutex.Lock()
+			bsp.batch = append(bsp.batch, sd)
+			shouldExport := len(bsp.batch) >= bsp.o.MaxExportBatchSize
+			bsp.batchMutex.Unlock()
+			if shouldExport {
+				if !bsp.timer.Stop() {
+					// Handle both GODEBUG=asynctimerchan=[0|1] properly.
+					select {
+					case <-bsp.timer.C:
+					default:
+					}
+				}
+				if err := bsp.exportSpans(ctx); err != nil {
+					otel.Handle(err)
+				}
+			}
+		}
+	}
+}
+
+// drainQueue awaits the any caller that had added to bsp.stopWait
+// to finish the enqueue, then exports the final batch.
+func (bsp *batchSpanProcessor) drainQueue() {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	for {
+		select {
+		case sd := <-bsp.queue:
+			if _, ok := sd.(forceFlushSpan); ok {
+				// Ignore flush requests as they are not valid spans.
+				continue
+			}
+
+			bsp.batchMutex.Lock()
+			bsp.batch = append(bsp.batch, sd)
+			shouldExport := len(bsp.batch) == bsp.o.MaxExportBatchSize
+			bsp.batchMutex.Unlock()
+
+			if shouldExport {
+				if err := bsp.exportSpans(ctx); err != nil {
+					otel.Handle(err)
+				}
+			}
+		default:
+			// There are no more enqueued spans. Make final export.
+			if err := bsp.exportSpans(ctx); err != nil {
+				otel.Handle(err)
+			}
+			return
+		}
+	}
+}
+
+func (bsp *batchSpanProcessor) enqueue(sd ReadOnlySpan) {
+	ctx := context.TODO()
+	if bsp.o.BlockOnQueueFull {
+		bsp.enqueueBlockOnQueueFull(ctx, sd)
+	} else {
+		bsp.enqueueDrop(ctx, sd)
+	}
+}
+
+func (bsp *batchSpanProcessor) enqueueBlockOnQueueFull(ctx context.Context, sd ReadOnlySpan) bool {
+	if !sd.SpanContext().IsSampled() {
+		return false
+	}
+
+	select {
+	case bsp.queue <- sd:
+		return true
+	case <-ctx.Done():
+		return false
+	}
+}
+
+func (bsp *batchSpanProcessor) enqueueDrop(_ context.Context, sd ReadOnlySpan) bool {
+	if !sd.SpanContext().IsSampled() {
+		return false
+	}
+
+	select {
+	case bsp.queue <- sd:
+		return true
+	default:
+		atomic.AddUint32(&bsp.dropped, 1)
+	}
+	return false
+}
+
+// MarshalLog is the marshaling function used by the logging system to represent this Span Processor.
+func (bsp *batchSpanProcessor) MarshalLog() interface{} {
+	return struct {
+		Type         string
+		SpanExporter SpanExporter
+		Config       BatchSpanProcessorOptions
+	}{
+		Type:         "BatchSpanProcessor",
+		SpanExporter: bsp.e,
+		Config:       bsp.o,
+	}
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/doc.go

@@ -0,0 +1,10 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+/*
+Package trace contains support for OpenTelemetry distributed tracing.
+
+The following assumes a basic familiarity with OpenTelemetry concepts.
+See https://opentelemetry.io.
+*/
+package trace // import "go.opentelemetry.io/otel/sdk/trace"

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/event.go

@@ -0,0 +1,26 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+)
+
+// Event is a thing that happened during a Span's lifetime.
+type Event struct {
+	// Name is the name of this event
+	Name string
+
+	// Attributes describe the aspects of the event.
+	Attributes []attribute.KeyValue
+
+	// DroppedAttributeCount is the number of attributes that were not
+	// recorded due to configured limits being reached.
+	DroppedAttributeCount int
+
+	// Time at which this event was recorded.
+	Time time.Time
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/evictedqueue.go

@@ -0,0 +1,64 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"slices"
+	"sync"
+
+	"go.opentelemetry.io/otel/internal/global"
+)
+
+// evictedQueue is a FIFO queue with a configurable capacity.
+type evictedQueue[T any] struct {
+	queue          []T
+	capacity       int
+	droppedCount   int
+	logDroppedMsg  string
+	logDroppedOnce sync.Once
+}
+
+func newEvictedQueueEvent(capacity int) evictedQueue[Event] {
+	// Do not pre-allocate queue, do this lazily.
+	return evictedQueue[Event]{
+		capacity:      capacity,
+		logDroppedMsg: "limit reached: dropping trace trace.Event",
+	}
+}
+
+func newEvictedQueueLink(capacity int) evictedQueue[Link] {
+	// Do not pre-allocate queue, do this lazily.
+	return evictedQueue[Link]{
+		capacity:      capacity,
+		logDroppedMsg: "limit reached: dropping trace trace.Link",
+	}
+}
+
+// add adds value to the evictedQueue eq. If eq is at capacity, the oldest
+// queued value will be discarded and the drop count incremented.
+func (eq *evictedQueue[T]) add(value T) {
+	if eq.capacity == 0 {
+		eq.droppedCount++
+		eq.logDropped()
+		return
+	}
+
+	if eq.capacity > 0 && len(eq.queue) == eq.capacity {
+		// Drop first-in while avoiding allocating more capacity to eq.queue.
+		copy(eq.queue[:eq.capacity-1], eq.queue[1:])
+		eq.queue = eq.queue[:eq.capacity-1]
+		eq.droppedCount++
+		eq.logDropped()
+	}
+	eq.queue = append(eq.queue, value)
+}
+
+func (eq *evictedQueue[T]) logDropped() {
+	eq.logDroppedOnce.Do(func() { global.Warn(eq.logDroppedMsg) })
+}
+
+// copy returns a copy of the evictedQueue.
+func (eq *evictedQueue[T]) copy() []T {
+	return slices.Clone(eq.queue)
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/id_generator.go

@@ -0,0 +1,81 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	crand "crypto/rand"
+	"encoding/binary"
+	"math/rand"
+	"sync"
+
+	"go.opentelemetry.io/otel/trace"
+)
+
+// IDGenerator allows custom generators for TraceID and SpanID.
+type IDGenerator interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// NewIDs returns a new trace and span ID.
+	NewIDs(ctx context.Context) (trace.TraceID, trace.SpanID)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// NewSpanID returns a ID for a new span in the trace with traceID.
+	NewSpanID(ctx context.Context, traceID trace.TraceID) trace.SpanID
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+type randomIDGenerator struct {
+	sync.Mutex
+	randSource *rand.Rand
+}
+
+var _ IDGenerator = &randomIDGenerator{}
+
+// NewSpanID returns a non-zero span ID from a randomly-chosen sequence.
+func (gen *randomIDGenerator) NewSpanID(ctx context.Context, traceID trace.TraceID) trace.SpanID {
+	gen.Lock()
+	defer gen.Unlock()
+	sid := trace.SpanID{}
+	for {
+		_, _ = gen.randSource.Read(sid[:])
+		if sid.IsValid() {
+			break
+		}
+	}
+	return sid
+}
+
+// NewIDs returns a non-zero trace ID and a non-zero span ID from a
+// randomly-chosen sequence.
+func (gen *randomIDGenerator) NewIDs(ctx context.Context) (trace.TraceID, trace.SpanID) {
+	gen.Lock()
+	defer gen.Unlock()
+	tid := trace.TraceID{}
+	sid := trace.SpanID{}
+	for {
+		_, _ = gen.randSource.Read(tid[:])
+		if tid.IsValid() {
+			break
+		}
+	}
+	for {
+		_, _ = gen.randSource.Read(sid[:])
+		if sid.IsValid() {
+			break
+		}
+	}
+	return tid, sid
+}
+
+func defaultIDGenerator() IDGenerator {
+	gen := &randomIDGenerator{}
+	var rngSeed int64
+	_ = binary.Read(crand.Reader, binary.LittleEndian, &rngSeed)
+	gen.randSource = rand.New(rand.NewSource(rngSeed))
+	return gen
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/link.go

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// Link is the relationship between two Spans. The relationship can be within
+// the same Trace or across different Traces.
+type Link struct {
+	// SpanContext of the linked Span.
+	SpanContext trace.SpanContext
+
+	// Attributes describe the aspects of the link.
+	Attributes []attribute.KeyValue
+
+	// DroppedAttributeCount is the number of attributes that were not
+	// recorded due to configured limits being reached.
+	DroppedAttributeCount int
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/provider.go

@@ -0,0 +1,494 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"sync/atomic"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/internal/global"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	"go.opentelemetry.io/otel/trace"
+	"go.opentelemetry.io/otel/trace/embedded"
+	"go.opentelemetry.io/otel/trace/noop"
+)
+
+const (
+	defaultTracerName = "go.opentelemetry.io/otel/sdk/tracer"
+)
+
+// tracerProviderConfig.
+type tracerProviderConfig struct {
+	// processors contains collection of SpanProcessors that are processing pipeline
+	// for spans in the trace signal.
+	// SpanProcessors registered with a TracerProvider and are called at the start
+	// and end of a Span's lifecycle, and are called in the order they are
+	// registered.
+	processors []SpanProcessor
+
+	// sampler is the default sampler used when creating new spans.
+	sampler Sampler
+
+	// idGenerator is used to generate all Span and Trace IDs when needed.
+	idGenerator IDGenerator
+
+	// spanLimits defines the attribute, event, and link limits for spans.
+	spanLimits SpanLimits
+
+	// resource contains attributes representing an entity that produces telemetry.
+	resource *resource.Resource
+}
+
+// MarshalLog is the marshaling function used by the logging system to represent this Provider.
+func (cfg tracerProviderConfig) MarshalLog() interface{} {
+	return struct {
+		SpanProcessors  []SpanProcessor
+		SamplerType     string
+		IDGeneratorType string
+		SpanLimits      SpanLimits
+		Resource        *resource.Resource
+	}{
+		SpanProcessors:  cfg.processors,
+		SamplerType:     fmt.Sprintf("%T", cfg.sampler),
+		IDGeneratorType: fmt.Sprintf("%T", cfg.idGenerator),
+		SpanLimits:      cfg.spanLimits,
+		Resource:        cfg.resource,
+	}
+}
+
+// TracerProvider is an OpenTelemetry TracerProvider. It provides Tracers to
+// instrumentation so it can trace operational flow through a system.
+type TracerProvider struct {
+	embedded.TracerProvider
+
+	mu             sync.Mutex
+	namedTracer    map[instrumentation.Scope]*tracer
+	spanProcessors atomic.Pointer[spanProcessorStates]
+
+	isShutdown atomic.Bool
+
+	// These fields are not protected by the lock mu. They are assumed to be
+	// immutable after creation of the TracerProvider.
+	sampler     Sampler
+	idGenerator IDGenerator
+	spanLimits  SpanLimits
+	resource    *resource.Resource
+}
+
+var _ trace.TracerProvider = &TracerProvider{}
+
+// NewTracerProvider returns a new and configured TracerProvider.
+//
+// By default the returned TracerProvider is configured with:
+//   - a ParentBased(AlwaysSample) Sampler
+//   - a random number IDGenerator
+//   - the resource.Default() Resource
+//   - the default SpanLimits.
+//
+// The passed opts are used to override these default values and configure the
+// returned TracerProvider appropriately.
+func NewTracerProvider(opts ...TracerProviderOption) *TracerProvider {
+	o := tracerProviderConfig{
+		spanLimits: NewSpanLimits(),
+	}
+	o = applyTracerProviderEnvConfigs(o)
+
+	for _, opt := range opts {
+		o = opt.apply(o)
+	}
+
+	o = ensureValidTracerProviderConfig(o)
+
+	tp := &TracerProvider{
+		namedTracer: make(map[instrumentation.Scope]*tracer),
+		sampler:     o.sampler,
+		idGenerator: o.idGenerator,
+		spanLimits:  o.spanLimits,
+		resource:    o.resource,
+	}
+	global.Info("TracerProvider created", "config", o)
+
+	spss := make(spanProcessorStates, 0, len(o.processors))
+	for _, sp := range o.processors {
+		spss = append(spss, newSpanProcessorState(sp))
+	}
+	tp.spanProcessors.Store(&spss)
+
+	return tp
+}
+
+// Tracer returns a Tracer with the given name and options. If a Tracer for
+// the given name and options does not exist it is created, otherwise the
+// existing Tracer is returned.
+//
+// If name is empty, DefaultTracerName is used instead.
+//
+// This method is safe to be called concurrently.
+func (p *TracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.Tracer {
+	// This check happens before the mutex is acquired to avoid deadlocking if Tracer() is called from within Shutdown().
+	if p.isShutdown.Load() {
+		return noop.NewTracerProvider().Tracer(name, opts...)
+	}
+	c := trace.NewTracerConfig(opts...)
+	if name == "" {
+		name = defaultTracerName
+	}
+	is := instrumentation.Scope{
+		Name:       name,
+		Version:    c.InstrumentationVersion(),
+		SchemaURL:  c.SchemaURL(),
+		Attributes: c.InstrumentationAttributes(),
+	}
+
+	t, ok := func() (trace.Tracer, bool) {
+		p.mu.Lock()
+		defer p.mu.Unlock()
+		// Must check the flag after acquiring the mutex to avoid returning a valid tracer if Shutdown() ran
+		// after the first check above but before we acquired the mutex.
+		if p.isShutdown.Load() {
+			return noop.NewTracerProvider().Tracer(name, opts...), true
+		}
+		t, ok := p.namedTracer[is]
+		if !ok {
+			t = &tracer{
+				provider:             p,
+				instrumentationScope: is,
+			}
+			p.namedTracer[is] = t
+		}
+		return t, ok
+	}()
+	if !ok {
+		// This code is outside the mutex to not hold the lock while calling third party logging code:
+		// - That code may do slow things like I/O, which would prolong the duration the lock is held,
+		//   slowing down all tracing consumers.
+		// - Logging code may be instrumented with tracing and deadlock because it could try
+		//   acquiring the same non-reentrant mutex.
+		global.Info("Tracer created", "name", name, "version", is.Version, "schemaURL", is.SchemaURL, "attributes", is.Attributes)
+	}
+	return t
+}
+
+// RegisterSpanProcessor adds the given SpanProcessor to the list of SpanProcessors.
+func (p *TracerProvider) RegisterSpanProcessor(sp SpanProcessor) {
+	// This check prevents calls during a shutdown.
+	if p.isShutdown.Load() {
+		return
+	}
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	// This check prevents calls after a shutdown.
+	if p.isShutdown.Load() {
+		return
+	}
+
+	current := p.getSpanProcessors()
+	newSPS := make(spanProcessorStates, 0, len(current)+1)
+	newSPS = append(newSPS, current...)
+	newSPS = append(newSPS, newSpanProcessorState(sp))
+	p.spanProcessors.Store(&newSPS)
+}
+
+// UnregisterSpanProcessor removes the given SpanProcessor from the list of SpanProcessors.
+func (p *TracerProvider) UnregisterSpanProcessor(sp SpanProcessor) {
+	// This check prevents calls during a shutdown.
+	if p.isShutdown.Load() {
+		return
+	}
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	// This check prevents calls after a shutdown.
+	if p.isShutdown.Load() {
+		return
+	}
+	old := p.getSpanProcessors()
+	if len(old) == 0 {
+		return
+	}
+	spss := make(spanProcessorStates, len(old))
+	copy(spss, old)
+
+	// stop the span processor if it is started and remove it from the list
+	var stopOnce *spanProcessorState
+	var idx int
+	for i, sps := range spss {
+		if sps.sp == sp {
+			stopOnce = sps
+			idx = i
+		}
+	}
+	if stopOnce != nil {
+		stopOnce.state.Do(func() {
+			if err := sp.Shutdown(context.Background()); err != nil {
+				otel.Handle(err)
+			}
+		})
+	}
+	if len(spss) > 1 {
+		copy(spss[idx:], spss[idx+1:])
+	}
+	spss[len(spss)-1] = nil
+	spss = spss[:len(spss)-1]
+
+	p.spanProcessors.Store(&spss)
+}
+
+// ForceFlush immediately exports all spans that have not yet been exported for
+// all the registered span processors.
+func (p *TracerProvider) ForceFlush(ctx context.Context) error {
+	spss := p.getSpanProcessors()
+	if len(spss) == 0 {
+		return nil
+	}
+
+	for _, sps := range spss {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
+
+		if err := sps.sp.ForceFlush(ctx); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Shutdown shuts down TracerProvider. All registered span processors are shut down
+// in the order they were registered and any held computational resources are released.
+// After Shutdown is called, all methods are no-ops.
+func (p *TracerProvider) Shutdown(ctx context.Context) error {
+	// This check prevents deadlocks in case of recursive shutdown.
+	if p.isShutdown.Load() {
+		return nil
+	}
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	// This check prevents calls after a shutdown has already been done concurrently.
+	if !p.isShutdown.CompareAndSwap(false, true) { // did toggle?
+		return nil
+	}
+
+	var retErr error
+	for _, sps := range p.getSpanProcessors() {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
+
+		var err error
+		sps.state.Do(func() {
+			err = sps.sp.Shutdown(ctx)
+		})
+		if err != nil {
+			if retErr == nil {
+				retErr = err
+			} else {
+				// Poor man's list of errors
+				retErr = fmt.Errorf("%w; %w", retErr, err)
+			}
+		}
+	}
+	p.spanProcessors.Store(&spanProcessorStates{})
+	return retErr
+}
+
+func (p *TracerProvider) getSpanProcessors() spanProcessorStates {
+	return *(p.spanProcessors.Load())
+}
+
+// TracerProviderOption configures a TracerProvider.
+type TracerProviderOption interface {
+	apply(tracerProviderConfig) tracerProviderConfig
+}
+
+type traceProviderOptionFunc func(tracerProviderConfig) tracerProviderConfig
+
+func (fn traceProviderOptionFunc) apply(cfg tracerProviderConfig) tracerProviderConfig {
+	return fn(cfg)
+}
+
+// WithSyncer registers the exporter with the TracerProvider using a
+// SimpleSpanProcessor.
+//
+// This is not recommended for production use. The synchronous nature of the
+// SimpleSpanProcessor that will wrap the exporter make it good for testing,
+// debugging, or showing examples of other feature, but it will be slow and
+// have a high computation resource usage overhead. The WithBatcher option is
+// recommended for production use instead.
+func WithSyncer(e SpanExporter) TracerProviderOption {
+	return WithSpanProcessor(NewSimpleSpanProcessor(e))
+}
+
+// WithBatcher registers the exporter with the TracerProvider using a
+// BatchSpanProcessor configured with the passed opts.
+func WithBatcher(e SpanExporter, opts ...BatchSpanProcessorOption) TracerProviderOption {
+	return WithSpanProcessor(NewBatchSpanProcessor(e, opts...))
+}
+
+// WithSpanProcessor registers the SpanProcessor with a TracerProvider.
+func WithSpanProcessor(sp SpanProcessor) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg tracerProviderConfig) tracerProviderConfig {
+		cfg.processors = append(cfg.processors, sp)
+		return cfg
+	})
+}
+
+// WithResource returns a TracerProviderOption that will configure the
+// Resource r as a TracerProvider's Resource. The configured Resource is
+// referenced by all the Tracers the TracerProvider creates. It represents the
+// entity producing telemetry.
+//
+// If this option is not used, the TracerProvider will use the
+// resource.Default() Resource by default.
+func WithResource(r *resource.Resource) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg tracerProviderConfig) tracerProviderConfig {
+		var err error
+		cfg.resource, err = resource.Merge(resource.Environment(), r)
+		if err != nil {
+			otel.Handle(err)
+		}
+		return cfg
+	})
+}
+
+// WithIDGenerator returns a TracerProviderOption that will configure the
+// IDGenerator g as a TracerProvider's IDGenerator. The configured IDGenerator
+// is used by the Tracers the TracerProvider creates to generate new Span and
+// Trace IDs.
+//
+// If this option is not used, the TracerProvider will use a random number
+// IDGenerator by default.
+func WithIDGenerator(g IDGenerator) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg tracerProviderConfig) tracerProviderConfig {
+		if g != nil {
+			cfg.idGenerator = g
+		}
+		return cfg
+	})
+}
+
+// WithSampler returns a TracerProviderOption that will configure the Sampler
+// s as a TracerProvider's Sampler. The configured Sampler is used by the
+// Tracers the TracerProvider creates to make their sampling decisions for the
+// Spans they create.
+//
+// This option overrides the Sampler configured through the OTEL_TRACES_SAMPLER
+// and OTEL_TRACES_SAMPLER_ARG environment variables. If this option is not used
+// and the sampler is not configured through environment variables or the environment
+// contains invalid/unsupported configuration, the TracerProvider will use a
+// ParentBased(AlwaysSample) Sampler by default.
+func WithSampler(s Sampler) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg tracerProviderConfig) tracerProviderConfig {
+		if s != nil {
+			cfg.sampler = s
+		}
+		return cfg
+	})
+}
+
+// WithSpanLimits returns a TracerProviderOption that configures a
+// TracerProvider to use the SpanLimits sl. These SpanLimits bound any Span
+// created by a Tracer from the TracerProvider.
+//
+// If any field of sl is zero or negative it will be replaced with the default
+// value for that field.
+//
+// If this or WithRawSpanLimits are not provided, the TracerProvider will use
+// the limits defined by environment variables, or the defaults if unset.
+// Refer to the NewSpanLimits documentation for information about this
+// relationship.
+//
+// Deprecated: Use WithRawSpanLimits instead which allows setting unlimited
+// and zero limits. This option will be kept until the next major version
+// incremented release.
+func WithSpanLimits(sl SpanLimits) TracerProviderOption {
+	if sl.AttributeValueLengthLimit <= 0 {
+		sl.AttributeValueLengthLimit = DefaultAttributeValueLengthLimit
+	}
+	if sl.AttributeCountLimit <= 0 {
+		sl.AttributeCountLimit = DefaultAttributeCountLimit
+	}
+	if sl.EventCountLimit <= 0 {
+		sl.EventCountLimit = DefaultEventCountLimit
+	}
+	if sl.AttributePerEventCountLimit <= 0 {
+		sl.AttributePerEventCountLimit = DefaultAttributePerEventCountLimit
+	}
+	if sl.LinkCountLimit <= 0 {
+		sl.LinkCountLimit = DefaultLinkCountLimit
+	}
+	if sl.AttributePerLinkCountLimit <= 0 {
+		sl.AttributePerLinkCountLimit = DefaultAttributePerLinkCountLimit
+	}
+	return traceProviderOptionFunc(func(cfg tracerProviderConfig) tracerProviderConfig {
+		cfg.spanLimits = sl
+		return cfg
+	})
+}
+
+// WithRawSpanLimits returns a TracerProviderOption that configures a
+// TracerProvider to use these limits. These limits bound any Span created by
+// a Tracer from the TracerProvider.
+//
+// The limits will be used as-is. Zero or negative values will not be changed
+// to the default value like WithSpanLimits does. Setting a limit to zero will
+// effectively disable the related resource it limits and setting to a
+// negative value will mean that resource is unlimited. Consequentially, this
+// means that the zero-value SpanLimits will disable all span resources.
+// Because of this, limits should be constructed using NewSpanLimits and
+// updated accordingly.
+//
+// If this or WithSpanLimits are not provided, the TracerProvider will use the
+// limits defined by environment variables, or the defaults if unset. Refer to
+// the NewSpanLimits documentation for information about this relationship.
+func WithRawSpanLimits(limits SpanLimits) TracerProviderOption {
+	return traceProviderOptionFunc(func(cfg tracerProviderConfig) tracerProviderConfig {
+		cfg.spanLimits = limits
+		return cfg
+	})
+}
+
+func applyTracerProviderEnvConfigs(cfg tracerProviderConfig) tracerProviderConfig {
+	for _, opt := range tracerProviderOptionsFromEnv() {
+		cfg = opt.apply(cfg)
+	}
+
+	return cfg
+}
+
+func tracerProviderOptionsFromEnv() []TracerProviderOption {
+	var opts []TracerProviderOption
+
+	sampler, err := samplerFromEnv()
+	if err != nil {
+		otel.Handle(err)
+	}
+
+	if sampler != nil {
+		opts = append(opts, WithSampler(sampler))
+	}
+
+	return opts
+}
+
+// ensureValidTracerProviderConfig ensures that given TracerProviderConfig is valid.
+func ensureValidTracerProviderConfig(cfg tracerProviderConfig) tracerProviderConfig {
+	if cfg.sampler == nil {
+		cfg.sampler = ParentBased(AlwaysSample())
+	}
+	if cfg.idGenerator == nil {
+		cfg.idGenerator = defaultIDGenerator()
+	}
+	if cfg.resource == nil {
+		cfg.resource = resource.Default()
+	}
+	return cfg
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/sampler_env.go

@@ -0,0 +1,97 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const (
+	tracesSamplerKey    = "OTEL_TRACES_SAMPLER"
+	tracesSamplerArgKey = "OTEL_TRACES_SAMPLER_ARG"
+
+	samplerAlwaysOn                = "always_on"
+	samplerAlwaysOff               = "always_off"
+	samplerTraceIDRatio            = "traceidratio"
+	samplerParentBasedAlwaysOn     = "parentbased_always_on"
+	samplerParsedBasedAlwaysOff    = "parentbased_always_off"
+	samplerParentBasedTraceIDRatio = "parentbased_traceidratio"
+)
+
+type errUnsupportedSampler string
+
+func (e errUnsupportedSampler) Error() string {
+	return fmt.Sprintf("unsupported sampler: %s", string(e))
+}
+
+var (
+	errNegativeTraceIDRatio       = errors.New("invalid trace ID ratio: less than 0.0")
+	errGreaterThanOneTraceIDRatio = errors.New("invalid trace ID ratio: greater than 1.0")
+)
+
+type samplerArgParseError struct {
+	parseErr error
+}
+
+func (e samplerArgParseError) Error() string {
+	return fmt.Sprintf("parsing sampler argument: %s", e.parseErr.Error())
+}
+
+func (e samplerArgParseError) Unwrap() error {
+	return e.parseErr
+}
+
+func samplerFromEnv() (Sampler, error) {
+	sampler, ok := os.LookupEnv(tracesSamplerKey)
+	if !ok {
+		return nil, nil
+	}
+
+	sampler = strings.ToLower(strings.TrimSpace(sampler))
+	samplerArg, hasSamplerArg := os.LookupEnv(tracesSamplerArgKey)
+	samplerArg = strings.TrimSpace(samplerArg)
+
+	switch sampler {
+	case samplerAlwaysOn:
+		return AlwaysSample(), nil
+	case samplerAlwaysOff:
+		return NeverSample(), nil
+	case samplerTraceIDRatio:
+		if !hasSamplerArg {
+			return TraceIDRatioBased(1.0), nil
+		}
+		return parseTraceIDRatio(samplerArg)
+	case samplerParentBasedAlwaysOn:
+		return ParentBased(AlwaysSample()), nil
+	case samplerParsedBasedAlwaysOff:
+		return ParentBased(NeverSample()), nil
+	case samplerParentBasedTraceIDRatio:
+		if !hasSamplerArg {
+			return ParentBased(TraceIDRatioBased(1.0)), nil
+		}
+		ratio, err := parseTraceIDRatio(samplerArg)
+		return ParentBased(ratio), err
+	default:
+		return nil, errUnsupportedSampler(sampler)
+	}
+}
+
+func parseTraceIDRatio(arg string) (Sampler, error) {
+	v, err := strconv.ParseFloat(arg, 64)
+	if err != nil {
+		return TraceIDRatioBased(1.0), samplerArgParseError{err}
+	}
+	if v < 0.0 {
+		return TraceIDRatioBased(1.0), errNegativeTraceIDRatio
+	}
+	if v > 1.0 {
+		return TraceIDRatioBased(1.0), errGreaterThanOneTraceIDRatio
+	}
+
+	return TraceIDRatioBased(v), nil
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/sampling.go

@@ -0,0 +1,282 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// Sampler decides whether a trace should be sampled and exported.
+type Sampler interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// ShouldSample returns a SamplingResult based on a decision made from the
+	// passed parameters.
+	ShouldSample(parameters SamplingParameters) SamplingResult
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Description returns information describing the Sampler.
+	Description() string
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+// SamplingParameters contains the values passed to a Sampler.
+type SamplingParameters struct {
+	ParentContext context.Context
+	TraceID       trace.TraceID
+	Name          string
+	Kind          trace.SpanKind
+	Attributes    []attribute.KeyValue
+	Links         []trace.Link
+}
+
+// SamplingDecision indicates whether a span is dropped, recorded and/or sampled.
+type SamplingDecision uint8
+
+// Valid sampling decisions.
+const (
+	// Drop will not record the span and all attributes/events will be dropped.
+	Drop SamplingDecision = iota
+
+	// Record indicates the span's `IsRecording() == true`, but `Sampled` flag
+	// *must not* be set.
+	RecordOnly
+
+	// RecordAndSample has span's `IsRecording() == true` and `Sampled` flag
+	// *must* be set.
+	RecordAndSample
+)
+
+// SamplingResult conveys a SamplingDecision, set of Attributes and a Tracestate.
+type SamplingResult struct {
+	Decision   SamplingDecision
+	Attributes []attribute.KeyValue
+	Tracestate trace.TraceState
+}
+
+type traceIDRatioSampler struct {
+	traceIDUpperBound uint64
+	description       string
+}
+
+func (ts traceIDRatioSampler) ShouldSample(p SamplingParameters) SamplingResult {
+	psc := trace.SpanContextFromContext(p.ParentContext)
+	x := binary.BigEndian.Uint64(p.TraceID[8:16]) >> 1
+	if x < ts.traceIDUpperBound {
+		return SamplingResult{
+			Decision:   RecordAndSample,
+			Tracestate: psc.TraceState(),
+		}
+	}
+	return SamplingResult{
+		Decision:   Drop,
+		Tracestate: psc.TraceState(),
+	}
+}
+
+func (ts traceIDRatioSampler) Description() string {
+	return ts.description
+}
+
+// TraceIDRatioBased samples a given fraction of traces. Fractions >= 1 will
+// always sample. Fractions < 0 are treated as zero. To respect the
+// parent trace's `SampledFlag`, the `TraceIDRatioBased` sampler should be used
+// as a delegate of a `Parent` sampler.
+//
+//nolint:revive // revive complains about stutter of `trace.TraceIDRatioBased`
+func TraceIDRatioBased(fraction float64) Sampler {
+	if fraction >= 1 {
+		return AlwaysSample()
+	}
+
+	if fraction <= 0 {
+		fraction = 0
+	}
+
+	return &traceIDRatioSampler{
+		traceIDUpperBound: uint64(fraction * (1 << 63)),
+		description:       fmt.Sprintf("TraceIDRatioBased{%g}", fraction),
+	}
+}
+
+type alwaysOnSampler struct{}
+
+func (as alwaysOnSampler) ShouldSample(p SamplingParameters) SamplingResult {
+	return SamplingResult{
+		Decision:   RecordAndSample,
+		Tracestate: trace.SpanContextFromContext(p.ParentContext).TraceState(),
+	}
+}
+
+func (as alwaysOnSampler) Description() string {
+	return "AlwaysOnSampler"
+}
+
+// AlwaysSample returns a Sampler that samples every trace.
+// Be careful about using this sampler in a production application with
+// significant traffic: a new trace will be started and exported for every
+// request.
+func AlwaysSample() Sampler {
+	return alwaysOnSampler{}
+}
+
+type alwaysOffSampler struct{}
+
+func (as alwaysOffSampler) ShouldSample(p SamplingParameters) SamplingResult {
+	return SamplingResult{
+		Decision:   Drop,
+		Tracestate: trace.SpanContextFromContext(p.ParentContext).TraceState(),
+	}
+}
+
+func (as alwaysOffSampler) Description() string {
+	return "AlwaysOffSampler"
+}
+
+// NeverSample returns a Sampler that samples no traces.
+func NeverSample() Sampler {
+	return alwaysOffSampler{}
+}
+
+// ParentBased returns a sampler decorator which behaves differently,
+// based on the parent of the span. If the span has no parent,
+// the decorated sampler is used to make sampling decision. If the span has
+// a parent, depending on whether the parent is remote and whether it
+// is sampled, one of the following samplers will apply:
+//   - remoteParentSampled(Sampler) (default: AlwaysOn)
+//   - remoteParentNotSampled(Sampler) (default: AlwaysOff)
+//   - localParentSampled(Sampler) (default: AlwaysOn)
+//   - localParentNotSampled(Sampler) (default: AlwaysOff)
+func ParentBased(root Sampler, samplers ...ParentBasedSamplerOption) Sampler {
+	return parentBased{
+		root:   root,
+		config: configureSamplersForParentBased(samplers),
+	}
+}
+
+type parentBased struct {
+	root   Sampler
+	config samplerConfig
+}
+
+func configureSamplersForParentBased(samplers []ParentBasedSamplerOption) samplerConfig {
+	c := samplerConfig{
+		remoteParentSampled:    AlwaysSample(),
+		remoteParentNotSampled: NeverSample(),
+		localParentSampled:     AlwaysSample(),
+		localParentNotSampled:  NeverSample(),
+	}
+
+	for _, so := range samplers {
+		c = so.apply(c)
+	}
+
+	return c
+}
+
+// samplerConfig is a group of options for parentBased sampler.
+type samplerConfig struct {
+	remoteParentSampled, remoteParentNotSampled Sampler
+	localParentSampled, localParentNotSampled   Sampler
+}
+
+// ParentBasedSamplerOption configures the sampler for a particular sampling case.
+type ParentBasedSamplerOption interface {
+	apply(samplerConfig) samplerConfig
+}
+
+// WithRemoteParentSampled sets the sampler for the case of sampled remote parent.
+func WithRemoteParentSampled(s Sampler) ParentBasedSamplerOption {
+	return remoteParentSampledOption{s}
+}
+
+type remoteParentSampledOption struct {
+	s Sampler
+}
+
+func (o remoteParentSampledOption) apply(config samplerConfig) samplerConfig {
+	config.remoteParentSampled = o.s
+	return config
+}
+
+// WithRemoteParentNotSampled sets the sampler for the case of remote parent
+// which is not sampled.
+func WithRemoteParentNotSampled(s Sampler) ParentBasedSamplerOption {
+	return remoteParentNotSampledOption{s}
+}
+
+type remoteParentNotSampledOption struct {
+	s Sampler
+}
+
+func (o remoteParentNotSampledOption) apply(config samplerConfig) samplerConfig {
+	config.remoteParentNotSampled = o.s
+	return config
+}
+
+// WithLocalParentSampled sets the sampler for the case of sampled local parent.
+func WithLocalParentSampled(s Sampler) ParentBasedSamplerOption {
+	return localParentSampledOption{s}
+}
+
+type localParentSampledOption struct {
+	s Sampler
+}
+
+func (o localParentSampledOption) apply(config samplerConfig) samplerConfig {
+	config.localParentSampled = o.s
+	return config
+}
+
+// WithLocalParentNotSampled sets the sampler for the case of local parent
+// which is not sampled.
+func WithLocalParentNotSampled(s Sampler) ParentBasedSamplerOption {
+	return localParentNotSampledOption{s}
+}
+
+type localParentNotSampledOption struct {
+	s Sampler
+}
+
+func (o localParentNotSampledOption) apply(config samplerConfig) samplerConfig {
+	config.localParentNotSampled = o.s
+	return config
+}
+
+func (pb parentBased) ShouldSample(p SamplingParameters) SamplingResult {
+	psc := trace.SpanContextFromContext(p.ParentContext)
+	if psc.IsValid() {
+		if psc.IsRemote() {
+			if psc.IsSampled() {
+				return pb.config.remoteParentSampled.ShouldSample(p)
+			}
+			return pb.config.remoteParentNotSampled.ShouldSample(p)
+		}
+
+		if psc.IsSampled() {
+			return pb.config.localParentSampled.ShouldSample(p)
+		}
+		return pb.config.localParentNotSampled.ShouldSample(p)
+	}
+	return pb.root.ShouldSample(p)
+}
+
+func (pb parentBased) Description() string {
+	return fmt.Sprintf("ParentBased{root:%s,remoteParentSampled:%s,"+
+		"remoteParentNotSampled:%s,localParentSampled:%s,localParentNotSampled:%s}",
+		pb.root.Description(),
+		pb.config.remoteParentSampled.Description(),
+		pb.config.remoteParentNotSampled.Description(),
+		pb.config.localParentSampled.Description(),
+		pb.config.localParentNotSampled.Description(),
+	)
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/simple_span_processor.go

@@ -0,0 +1,121 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"sync"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/internal/global"
+)
+
+// simpleSpanProcessor is a SpanProcessor that synchronously sends all
+// completed Spans to a trace.Exporter immediately.
+type simpleSpanProcessor struct {
+	exporterMu sync.Mutex
+	exporter   SpanExporter
+	stopOnce   sync.Once
+}
+
+var _ SpanProcessor = (*simpleSpanProcessor)(nil)
+
+// NewSimpleSpanProcessor returns a new SpanProcessor that will synchronously
+// send completed spans to the exporter immediately.
+//
+// This SpanProcessor is not recommended for production use. The synchronous
+// nature of this SpanProcessor makes it good for testing, debugging, or showing
+// examples of other features, but it will be slow and have a high computation
+// resource usage overhead. The BatchSpanProcessor is recommended for production
+// use instead.
+func NewSimpleSpanProcessor(exporter SpanExporter) SpanProcessor {
+	ssp := &simpleSpanProcessor{
+		exporter: exporter,
+	}
+	global.Warn("SimpleSpanProcessor is not recommended for production use, consider using BatchSpanProcessor instead.")
+
+	return ssp
+}
+
+// OnStart does nothing.
+func (ssp *simpleSpanProcessor) OnStart(context.Context, ReadWriteSpan) {}
+
+// OnEnd immediately exports a ReadOnlySpan.
+func (ssp *simpleSpanProcessor) OnEnd(s ReadOnlySpan) {
+	ssp.exporterMu.Lock()
+	defer ssp.exporterMu.Unlock()
+
+	if ssp.exporter != nil && s.SpanContext().TraceFlags().IsSampled() {
+		if err := ssp.exporter.ExportSpans(context.Background(), []ReadOnlySpan{s}); err != nil {
+			otel.Handle(err)
+		}
+	}
+}
+
+// Shutdown shuts down the exporter this SimpleSpanProcessor exports to.
+func (ssp *simpleSpanProcessor) Shutdown(ctx context.Context) error {
+	var err error
+	ssp.stopOnce.Do(func() {
+		stopFunc := func(exp SpanExporter) (<-chan error, func()) {
+			done := make(chan error)
+			return done, func() { done <- exp.Shutdown(ctx) }
+		}
+
+		// The exporter field of the simpleSpanProcessor needs to be zeroed to
+		// signal it is shut down, meaning all subsequent calls to OnEnd will
+		// be gracefully ignored. This needs to be done synchronously to avoid
+		// any race condition.
+		//
+		// A closure is used to keep reference to the exporter and then the
+		// field is zeroed. This ensures the simpleSpanProcessor is shut down
+		// before the exporter. This order is important as it avoids a potential
+		// deadlock. If the exporter shut down operation generates a span, that
+		// span would need to be exported. Meaning, OnEnd would be called and
+		// try acquiring the lock that is held here.
+		ssp.exporterMu.Lock()
+		done, shutdown := stopFunc(ssp.exporter)
+		ssp.exporter = nil
+		ssp.exporterMu.Unlock()
+
+		go shutdown()
+
+		// Wait for the exporter to shut down or the deadline to expire.
+		select {
+		case err = <-done:
+		case <-ctx.Done():
+			// It is possible for the exporter to have immediately shut down and
+			// the context to be done simultaneously. In that case this outer
+			// select statement will randomly choose a case. This will result in
+			// a different returned error for similar scenarios. Instead, double
+			// check if the exporter shut down at the same time and return that
+			// error if so. This will ensure consistency as well as ensure
+			// the caller knows the exporter shut down successfully (they can
+			// already determine if the deadline is expired given they passed
+			// the context).
+			select {
+			case err = <-done:
+			default:
+				err = ctx.Err()
+			}
+		}
+	})
+	return err
+}
+
+// ForceFlush does nothing as there is no data to flush.
+func (ssp *simpleSpanProcessor) ForceFlush(context.Context) error {
+	return nil
+}
+
+// MarshalLog is the marshaling function used by the logging system to represent
+// this Span Processor.
+func (ssp *simpleSpanProcessor) MarshalLog() interface{} {
+	return struct {
+		Type     string
+		Exporter SpanExporter
+	}{
+		Type:     "SimpleSpanProcessor",
+		Exporter: ssp.exporter,
+	}
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/snapshot.go

@@ -0,0 +1,133 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"time"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// snapshot is an record of a spans state at a particular checkpointed time.
+// It is used as a read-only representation of that state.
+type snapshot struct {
+	name                  string
+	spanContext           trace.SpanContext
+	parent                trace.SpanContext
+	spanKind              trace.SpanKind
+	startTime             time.Time
+	endTime               time.Time
+	attributes            []attribute.KeyValue
+	events                []Event
+	links                 []Link
+	status                Status
+	childSpanCount        int
+	droppedAttributeCount int
+	droppedEventCount     int
+	droppedLinkCount      int
+	resource              *resource.Resource
+	instrumentationScope  instrumentation.Scope
+}
+
+var _ ReadOnlySpan = snapshot{}
+
+func (s snapshot) private() {}
+
+// Name returns the name of the span.
+func (s snapshot) Name() string {
+	return s.name
+}
+
+// SpanContext returns the unique SpanContext that identifies the span.
+func (s snapshot) SpanContext() trace.SpanContext {
+	return s.spanContext
+}
+
+// Parent returns the unique SpanContext that identifies the parent of the
+// span if one exists. If the span has no parent the returned SpanContext
+// will be invalid.
+func (s snapshot) Parent() trace.SpanContext {
+	return s.parent
+}
+
+// SpanKind returns the role the span plays in a Trace.
+func (s snapshot) SpanKind() trace.SpanKind {
+	return s.spanKind
+}
+
+// StartTime returns the time the span started recording.
+func (s snapshot) StartTime() time.Time {
+	return s.startTime
+}
+
+// EndTime returns the time the span stopped recording. It will be zero if
+// the span has not ended.
+func (s snapshot) EndTime() time.Time {
+	return s.endTime
+}
+
+// Attributes returns the defining attributes of the span.
+func (s snapshot) Attributes() []attribute.KeyValue {
+	return s.attributes
+}
+
+// Links returns all the links the span has to other spans.
+func (s snapshot) Links() []Link {
+	return s.links
+}
+
+// Events returns all the events that occurred within in the spans
+// lifetime.
+func (s snapshot) Events() []Event {
+	return s.events
+}
+
+// Status returns the spans status.
+func (s snapshot) Status() Status {
+	return s.status
+}
+
+// InstrumentationScope returns information about the instrumentation
+// scope that created the span.
+func (s snapshot) InstrumentationScope() instrumentation.Scope {
+	return s.instrumentationScope
+}
+
+// InstrumentationLibrary returns information about the instrumentation
+// library that created the span.
+func (s snapshot) InstrumentationLibrary() instrumentation.Library { //nolint:staticcheck // This method needs to be define for backwards compatibility
+	return s.instrumentationScope
+}
+
+// Resource returns information about the entity that produced the span.
+func (s snapshot) Resource() *resource.Resource {
+	return s.resource
+}
+
+// DroppedAttributes returns the number of attributes dropped by the span
+// due to limits being reached.
+func (s snapshot) DroppedAttributes() int {
+	return s.droppedAttributeCount
+}
+
+// DroppedLinks returns the number of links dropped by the span due to limits
+// being reached.
+func (s snapshot) DroppedLinks() int {
+	return s.droppedLinkCount
+}
+
+// DroppedEvents returns the number of events dropped by the span due to
+// limits being reached.
+func (s snapshot) DroppedEvents() int {
+	return s.droppedEventCount
+}
+
+// ChildSpanCount returns the count of spans that consider the span a
+// direct parent.
+func (s snapshot) ChildSpanCount() int {
+	return s.childSpanCount
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/span.go

@@ -0,0 +1,892 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"runtime"
+	rt "runtime/trace"
+	"slices"
+	"strings"
+	"sync"
+	"time"
+	"unicode/utf8"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/internal/global"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
+	"go.opentelemetry.io/otel/trace"
+	"go.opentelemetry.io/otel/trace/embedded"
+)
+
+// ReadOnlySpan allows reading information from the data structure underlying a
+// trace.Span. It is used in places where reading information from a span is
+// necessary but changing the span isn't necessary or allowed.
+//
+// Warning: methods may be added to this interface in minor releases.
+type ReadOnlySpan interface {
+	// Name returns the name of the span.
+	Name() string
+	// SpanContext returns the unique SpanContext that identifies the span.
+	SpanContext() trace.SpanContext
+	// Parent returns the unique SpanContext that identifies the parent of the
+	// span if one exists. If the span has no parent the returned SpanContext
+	// will be invalid.
+	Parent() trace.SpanContext
+	// SpanKind returns the role the span plays in a Trace.
+	SpanKind() trace.SpanKind
+	// StartTime returns the time the span started recording.
+	StartTime() time.Time
+	// EndTime returns the time the span stopped recording. It will be zero if
+	// the span has not ended.
+	EndTime() time.Time
+	// Attributes returns the defining attributes of the span.
+	// The order of the returned attributes is not guaranteed to be stable across invocations.
+	Attributes() []attribute.KeyValue
+	// Links returns all the links the span has to other spans.
+	Links() []Link
+	// Events returns all the events that occurred within in the spans
+	// lifetime.
+	Events() []Event
+	// Status returns the spans status.
+	Status() Status
+	// InstrumentationScope returns information about the instrumentation
+	// scope that created the span.
+	InstrumentationScope() instrumentation.Scope
+	// InstrumentationLibrary returns information about the instrumentation
+	// library that created the span.
+	// Deprecated: please use InstrumentationScope instead.
+	InstrumentationLibrary() instrumentation.Library //nolint:staticcheck // This method needs to be define for backwards compatibility
+	// Resource returns information about the entity that produced the span.
+	Resource() *resource.Resource
+	// DroppedAttributes returns the number of attributes dropped by the span
+	// due to limits being reached.
+	DroppedAttributes() int
+	// DroppedLinks returns the number of links dropped by the span due to
+	// limits being reached.
+	DroppedLinks() int
+	// DroppedEvents returns the number of events dropped by the span due to
+	// limits being reached.
+	DroppedEvents() int
+	// ChildSpanCount returns the count of spans that consider the span a
+	// direct parent.
+	ChildSpanCount() int
+
+	// A private method to prevent users implementing the
+	// interface and so future additions to it will not
+	// violate compatibility.
+	private()
+}
+
+// ReadWriteSpan exposes the same methods as trace.Span and in addition allows
+// reading information from the underlying data structure.
+// This interface exposes the union of the methods of trace.Span (which is a
+// "write-only" span) and ReadOnlySpan. New methods for writing or reading span
+// information should be added under trace.Span or ReadOnlySpan, respectively.
+//
+// Warning: methods may be added to this interface in minor releases.
+type ReadWriteSpan interface {
+	trace.Span
+	ReadOnlySpan
+}
+
+// recordingSpan is an implementation of the OpenTelemetry Span API
+// representing the individual component of a trace that is sampled.
+type recordingSpan struct {
+	embedded.Span
+
+	// mu protects the contents of this span.
+	mu sync.Mutex
+
+	// parent holds the parent span of this span as a trace.SpanContext.
+	parent trace.SpanContext
+
+	// spanKind represents the kind of this span as a trace.SpanKind.
+	spanKind trace.SpanKind
+
+	// name is the name of this span.
+	name string
+
+	// startTime is the time at which this span was started.
+	startTime time.Time
+
+	// endTime is the time at which this span was ended. It contains the zero
+	// value of time.Time until the span is ended.
+	endTime time.Time
+
+	// status is the status of this span.
+	status Status
+
+	// childSpanCount holds the number of child spans created for this span.
+	childSpanCount int
+
+	// spanContext holds the SpanContext of this span.
+	spanContext trace.SpanContext
+
+	// attributes is a collection of user provided key/values. The collection
+	// is constrained by a configurable maximum held by the parent
+	// TracerProvider. When additional attributes are added after this maximum
+	// is reached these attributes the user is attempting to add are dropped.
+	// This dropped number of attributes is tracked and reported in the
+	// ReadOnlySpan exported when the span ends.
+	attributes        []attribute.KeyValue
+	droppedAttributes int
+	logDropAttrsOnce  sync.Once
+
+	// events are stored in FIFO queue capped by configured limit.
+	events evictedQueue[Event]
+
+	// links are stored in FIFO queue capped by configured limit.
+	links evictedQueue[Link]
+
+	// executionTracerTaskEnd ends the execution tracer span.
+	executionTracerTaskEnd func()
+
+	// tracer is the SDK tracer that created this span.
+	tracer *tracer
+}
+
+var (
+	_ ReadWriteSpan = (*recordingSpan)(nil)
+	_ runtimeTracer = (*recordingSpan)(nil)
+)
+
+// SpanContext returns the SpanContext of this span.
+func (s *recordingSpan) SpanContext() trace.SpanContext {
+	if s == nil {
+		return trace.SpanContext{}
+	}
+	return s.spanContext
+}
+
+// IsRecording returns if this span is being recorded. If this span has ended
+// this will return false.
+func (s *recordingSpan) IsRecording() bool {
+	if s == nil {
+		return false
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	return s.isRecording()
+}
+
+// isRecording returns if this span is being recorded. If this span has ended
+// this will return false.
+//
+// This method assumes s.mu.Lock is held by the caller.
+func (s *recordingSpan) isRecording() bool {
+	if s == nil {
+		return false
+	}
+	return s.endTime.IsZero()
+}
+
+// SetStatus sets the status of the Span in the form of a code and a
+// description, overriding previous values set. The description is only
+// included in the set status when the code is for an error. If this span is
+// not being recorded than this method does nothing.
+func (s *recordingSpan) SetStatus(code codes.Code, description string) {
+	if s == nil {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+	if s.status.Code > code {
+		return
+	}
+
+	status := Status{Code: code}
+	if code == codes.Error {
+		status.Description = description
+	}
+
+	s.status = status
+}
+
+// SetAttributes sets attributes of this span.
+//
+// If a key from attributes already exists the value associated with that key
+// will be overwritten with the value contained in attributes.
+//
+// If this span is not being recorded than this method does nothing.
+//
+// If adding attributes to the span would exceed the maximum amount of
+// attributes the span is configured to have, the last added attributes will
+// be dropped.
+func (s *recordingSpan) SetAttributes(attributes ...attribute.KeyValue) {
+	if s == nil || len(attributes) == 0 {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+
+	limit := s.tracer.provider.spanLimits.AttributeCountLimit
+	if limit == 0 {
+		// No attributes allowed.
+		s.addDroppedAttr(len(attributes))
+		return
+	}
+
+	// If adding these attributes could exceed the capacity of s perform a
+	// de-duplication and truncation while adding to avoid over allocation.
+	if limit > 0 && len(s.attributes)+len(attributes) > limit {
+		s.addOverCapAttrs(limit, attributes)
+		return
+	}
+
+	// Otherwise, add without deduplication. When attributes are read they
+	// will be deduplicated, optimizing the operation.
+	s.attributes = slices.Grow(s.attributes, len(attributes))
+	for _, a := range attributes {
+		if !a.Valid() {
+			// Drop all invalid attributes.
+			s.addDroppedAttr(1)
+			continue
+		}
+		a = truncateAttr(s.tracer.provider.spanLimits.AttributeValueLengthLimit, a)
+		s.attributes = append(s.attributes, a)
+	}
+}
+
+// Declared as a var so tests can override.
+var logDropAttrs = func() {
+	global.Warn("limit reached: dropping trace Span attributes")
+}
+
+// addDroppedAttr adds incr to the count of dropped attributes.
+//
+// The first, and only the first, time this method is called a warning will be
+// logged.
+//
+// This method assumes s.mu.Lock is held by the caller.
+func (s *recordingSpan) addDroppedAttr(incr int) {
+	s.droppedAttributes += incr
+	s.logDropAttrsOnce.Do(logDropAttrs)
+}
+
+// addOverCapAttrs adds the attributes attrs to the span s while
+// de-duplicating the attributes of s and attrs and dropping attributes that
+// exceed the limit.
+//
+// This method assumes s.mu.Lock is held by the caller.
+//
+// This method should only be called when there is a possibility that adding
+// attrs to s will exceed the limit. Otherwise, attrs should be added to s
+// without checking for duplicates and all retrieval methods of the attributes
+// for s will de-duplicate as needed.
+//
+// This method assumes limit is a value > 0. The argument should be validated
+// by the caller.
+func (s *recordingSpan) addOverCapAttrs(limit int, attrs []attribute.KeyValue) {
+	// In order to not allocate more capacity to s.attributes than needed,
+	// prune and truncate this addition of attributes while adding.
+
+	// Do not set a capacity when creating this map. Benchmark testing has
+	// showed this to only add unused memory allocations in general use.
+	exists := make(map[attribute.Key]int, len(s.attributes))
+	s.dedupeAttrsFromRecord(exists)
+
+	// Now that s.attributes is deduplicated, adding unique attributes up to
+	// the capacity of s will not over allocate s.attributes.
+
+	// max size = limit
+	maxCap := min(len(attrs)+len(s.attributes), limit)
+	if cap(s.attributes) < maxCap {
+		s.attributes = slices.Grow(s.attributes, maxCap-cap(s.attributes))
+	}
+	for _, a := range attrs {
+		if !a.Valid() {
+			// Drop all invalid attributes.
+			s.addDroppedAttr(1)
+			continue
+		}
+
+		if idx, ok := exists[a.Key]; ok {
+			// Perform all updates before dropping, even when at capacity.
+			a = truncateAttr(s.tracer.provider.spanLimits.AttributeValueLengthLimit, a)
+			s.attributes[idx] = a
+			continue
+		}
+
+		if len(s.attributes) >= limit {
+			// Do not just drop all of the remaining attributes, make sure
+			// updates are checked and performed.
+			s.addDroppedAttr(1)
+		} else {
+			a = truncateAttr(s.tracer.provider.spanLimits.AttributeValueLengthLimit, a)
+			s.attributes = append(s.attributes, a)
+			exists[a.Key] = len(s.attributes) - 1
+		}
+	}
+}
+
+// truncateAttr returns a truncated version of attr. Only string and string
+// slice attribute values are truncated. String values are truncated to at
+// most a length of limit. Each string slice value is truncated in this fashion
+// (the slice length itself is unaffected).
+//
+// No truncation is performed for a negative limit.
+func truncateAttr(limit int, attr attribute.KeyValue) attribute.KeyValue {
+	if limit < 0 {
+		return attr
+	}
+	switch attr.Value.Type() {
+	case attribute.STRING:
+		if v := attr.Value.AsString(); len(v) > limit {
+			return attr.Key.String(safeTruncate(v, limit))
+		}
+	case attribute.STRINGSLICE:
+		v := attr.Value.AsStringSlice()
+		for i := range v {
+			if len(v[i]) > limit {
+				v[i] = safeTruncate(v[i], limit)
+			}
+		}
+		return attr.Key.StringSlice(v)
+	}
+	return attr
+}
+
+// safeTruncate truncates the string and guarantees valid UTF-8 is returned.
+func safeTruncate(input string, limit int) string {
+	if trunc, ok := safeTruncateValidUTF8(input, limit); ok {
+		return trunc
+	}
+	trunc, _ := safeTruncateValidUTF8(strings.ToValidUTF8(input, ""), limit)
+	return trunc
+}
+
+// safeTruncateValidUTF8 returns a copy of the input string safely truncated to
+// limit. The truncation is ensured to occur at the bounds of complete UTF-8
+// characters. If invalid encoding of UTF-8 is encountered, input is returned
+// with false, otherwise, the truncated input will be returned with true.
+func safeTruncateValidUTF8(input string, limit int) (string, bool) {
+	for cnt := 0; cnt <= limit; {
+		r, size := utf8.DecodeRuneInString(input[cnt:])
+		if r == utf8.RuneError {
+			return input, false
+		}
+
+		if cnt+size > limit {
+			return input[:cnt], true
+		}
+		cnt += size
+	}
+	return input, true
+}
+
+// End ends the span. This method does nothing if the span is already ended or
+// is not being recorded.
+//
+// The only SpanOption currently supported is WithTimestamp which will set the
+// end time for a Span's life-cycle.
+//
+// If this method is called while panicking an error event is added to the
+// Span before ending it and the panic is continued.
+func (s *recordingSpan) End(options ...trace.SpanEndOption) {
+	// Do not start by checking if the span is being recorded which requires
+	// acquiring a lock. Make a minimal check that the span is not nil.
+	if s == nil {
+		return
+	}
+
+	// Store the end time as soon as possible to avoid artificially increasing
+	// the span's duration in case some operation below takes a while.
+	et := monotonicEndTime(s.startTime)
+
+	// Lock the span now that we have an end time and see if we need to do any more processing.
+	s.mu.Lock()
+	if !s.isRecording() {
+		s.mu.Unlock()
+		return
+	}
+
+	config := trace.NewSpanEndConfig(options...)
+	if recovered := recover(); recovered != nil {
+		// Record but don't stop the panic.
+		defer panic(recovered)
+		opts := []trace.EventOption{
+			trace.WithAttributes(
+				semconv.ExceptionType(typeStr(recovered)),
+				semconv.ExceptionMessage(fmt.Sprint(recovered)),
+			),
+		}
+
+		if config.StackTrace() {
+			opts = append(opts, trace.WithAttributes(
+				semconv.ExceptionStacktrace(recordStackTrace()),
+			))
+		}
+
+		s.addEvent(semconv.ExceptionEventName, opts...)
+	}
+
+	if s.executionTracerTaskEnd != nil {
+		s.mu.Unlock()
+		s.executionTracerTaskEnd()
+		s.mu.Lock()
+	}
+
+	// Setting endTime to non-zero marks the span as ended and not recording.
+	if config.Timestamp().IsZero() {
+		s.endTime = et
+	} else {
+		s.endTime = config.Timestamp()
+	}
+	s.mu.Unlock()
+
+	sps := s.tracer.provider.getSpanProcessors()
+	if len(sps) == 0 {
+		return
+	}
+	snap := s.snapshot()
+	for _, sp := range sps {
+		sp.sp.OnEnd(snap)
+	}
+}
+
+// monotonicEndTime returns the end time at present but offset from start,
+// monotonically.
+//
+// The monotonic clock is used in subtractions hence the duration since start
+// added back to start gives end as a monotonic time. See
+// https://golang.org/pkg/time/#hdr-Monotonic_Clocks
+func monotonicEndTime(start time.Time) time.Time {
+	return start.Add(time.Since(start))
+}
+
+// RecordError will record err as a span event for this span. An additional call to
+// SetStatus is required if the Status of the Span should be set to Error, this method
+// does not change the Span status. If this span is not being recorded or err is nil
+// than this method does nothing.
+func (s *recordingSpan) RecordError(err error, opts ...trace.EventOption) {
+	if s == nil || err == nil {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+
+	opts = append(opts, trace.WithAttributes(
+		semconv.ExceptionType(typeStr(err)),
+		semconv.ExceptionMessage(err.Error()),
+	))
+
+	c := trace.NewEventConfig(opts...)
+	if c.StackTrace() {
+		opts = append(opts, trace.WithAttributes(
+			semconv.ExceptionStacktrace(recordStackTrace()),
+		))
+	}
+
+	s.addEvent(semconv.ExceptionEventName, opts...)
+}
+
+func typeStr(i interface{}) string {
+	t := reflect.TypeOf(i)
+	if t.PkgPath() == "" && t.Name() == "" {
+		// Likely a builtin type.
+		return t.String()
+	}
+	return fmt.Sprintf("%s.%s", t.PkgPath(), t.Name())
+}
+
+func recordStackTrace() string {
+	stackTrace := make([]byte, 2048)
+	n := runtime.Stack(stackTrace, false)
+
+	return string(stackTrace[0:n])
+}
+
+// AddEvent adds an event with the provided name and options. If this span is
+// not being recorded then this method does nothing.
+func (s *recordingSpan) AddEvent(name string, o ...trace.EventOption) {
+	if s == nil {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+	s.addEvent(name, o...)
+}
+
+// addEvent adds an event with the provided name and options.
+//
+// This method assumes s.mu.Lock is held by the caller.
+func (s *recordingSpan) addEvent(name string, o ...trace.EventOption) {
+	c := trace.NewEventConfig(o...)
+	e := Event{Name: name, Attributes: c.Attributes(), Time: c.Timestamp()}
+
+	// Discard attributes over limit.
+	limit := s.tracer.provider.spanLimits.AttributePerEventCountLimit
+	if limit == 0 {
+		// Drop all attributes.
+		e.DroppedAttributeCount = len(e.Attributes)
+		e.Attributes = nil
+	} else if limit > 0 && len(e.Attributes) > limit {
+		// Drop over capacity.
+		e.DroppedAttributeCount = len(e.Attributes) - limit
+		e.Attributes = e.Attributes[:limit]
+	}
+
+	s.events.add(e)
+}
+
+// SetName sets the name of this span. If this span is not being recorded than
+// this method does nothing.
+func (s *recordingSpan) SetName(name string) {
+	if s == nil {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+	s.name = name
+}
+
+// Name returns the name of this span.
+func (s *recordingSpan) Name() string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.name
+}
+
+// Name returns the SpanContext of this span's parent span.
+func (s *recordingSpan) Parent() trace.SpanContext {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.parent
+}
+
+// SpanKind returns the SpanKind of this span.
+func (s *recordingSpan) SpanKind() trace.SpanKind {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.spanKind
+}
+
+// StartTime returns the time this span started.
+func (s *recordingSpan) StartTime() time.Time {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.startTime
+}
+
+// EndTime returns the time this span ended. For spans that have not yet
+// ended, the returned value will be the zero value of time.Time.
+func (s *recordingSpan) EndTime() time.Time {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.endTime
+}
+
+// Attributes returns the attributes of this span.
+//
+// The order of the returned attributes is not guaranteed to be stable.
+func (s *recordingSpan) Attributes() []attribute.KeyValue {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.dedupeAttrs()
+	return s.attributes
+}
+
+// dedupeAttrs deduplicates the attributes of s to fit capacity.
+//
+// This method assumes s.mu.Lock is held by the caller.
+func (s *recordingSpan) dedupeAttrs() {
+	// Do not set a capacity when creating this map. Benchmark testing has
+	// showed this to only add unused memory allocations in general use.
+	exists := make(map[attribute.Key]int, len(s.attributes))
+	s.dedupeAttrsFromRecord(exists)
+}
+
+// dedupeAttrsFromRecord deduplicates the attributes of s to fit capacity
+// using record as the record of unique attribute keys to their index.
+//
+// This method assumes s.mu.Lock is held by the caller.
+func (s *recordingSpan) dedupeAttrsFromRecord(record map[attribute.Key]int) {
+	// Use the fact that slices share the same backing array.
+	unique := s.attributes[:0]
+	for _, a := range s.attributes {
+		if idx, ok := record[a.Key]; ok {
+			unique[idx] = a
+		} else {
+			unique = append(unique, a)
+			record[a.Key] = len(unique) - 1
+		}
+	}
+	clear(s.attributes[len(unique):]) // Erase unneeded elements to let GC collect objects.
+	s.attributes = unique
+}
+
+// Links returns the links of this span.
+func (s *recordingSpan) Links() []Link {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if len(s.links.queue) == 0 {
+		return []Link{}
+	}
+	return s.links.copy()
+}
+
+// Events returns the events of this span.
+func (s *recordingSpan) Events() []Event {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if len(s.events.queue) == 0 {
+		return []Event{}
+	}
+	return s.events.copy()
+}
+
+// Status returns the status of this span.
+func (s *recordingSpan) Status() Status {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.status
+}
+
+// InstrumentationScope returns the instrumentation.Scope associated with
+// the Tracer that created this span.
+func (s *recordingSpan) InstrumentationScope() instrumentation.Scope {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.tracer.instrumentationScope
+}
+
+// InstrumentationLibrary returns the instrumentation.Library associated with
+// the Tracer that created this span.
+func (s *recordingSpan) InstrumentationLibrary() instrumentation.Library { //nolint:staticcheck // This method needs to be define for backwards compatibility
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.tracer.instrumentationScope
+}
+
+// Resource returns the Resource associated with the Tracer that created this
+// span.
+func (s *recordingSpan) Resource() *resource.Resource {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.tracer.provider.resource
+}
+
+func (s *recordingSpan) AddLink(link trace.Link) {
+	if s == nil {
+		return
+	}
+	if !link.SpanContext.IsValid() && len(link.Attributes) == 0 &&
+		link.SpanContext.TraceState().Len() == 0 {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+
+	l := Link{SpanContext: link.SpanContext, Attributes: link.Attributes}
+
+	// Discard attributes over limit.
+	limit := s.tracer.provider.spanLimits.AttributePerLinkCountLimit
+	if limit == 0 {
+		// Drop all attributes.
+		l.DroppedAttributeCount = len(l.Attributes)
+		l.Attributes = nil
+	} else if limit > 0 && len(l.Attributes) > limit {
+		l.DroppedAttributeCount = len(l.Attributes) - limit
+		l.Attributes = l.Attributes[:limit]
+	}
+
+	s.links.add(l)
+}
+
+// DroppedAttributes returns the number of attributes dropped by the span
+// due to limits being reached.
+func (s *recordingSpan) DroppedAttributes() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.droppedAttributes
+}
+
+// DroppedLinks returns the number of links dropped by the span due to limits
+// being reached.
+func (s *recordingSpan) DroppedLinks() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.links.droppedCount
+}
+
+// DroppedEvents returns the number of events dropped by the span due to
+// limits being reached.
+func (s *recordingSpan) DroppedEvents() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.events.droppedCount
+}
+
+// ChildSpanCount returns the count of spans that consider the span a
+// direct parent.
+func (s *recordingSpan) ChildSpanCount() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.childSpanCount
+}
+
+// TracerProvider returns a trace.TracerProvider that can be used to generate
+// additional Spans on the same telemetry pipeline as the current Span.
+func (s *recordingSpan) TracerProvider() trace.TracerProvider {
+	return s.tracer.provider
+}
+
+// snapshot creates a read-only copy of the current state of the span.
+func (s *recordingSpan) snapshot() ReadOnlySpan {
+	var sd snapshot
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	sd.endTime = s.endTime
+	sd.instrumentationScope = s.tracer.instrumentationScope
+	sd.name = s.name
+	sd.parent = s.parent
+	sd.resource = s.tracer.provider.resource
+	sd.spanContext = s.spanContext
+	sd.spanKind = s.spanKind
+	sd.startTime = s.startTime
+	sd.status = s.status
+	sd.childSpanCount = s.childSpanCount
+
+	if len(s.attributes) > 0 {
+		s.dedupeAttrs()
+		sd.attributes = s.attributes
+	}
+	sd.droppedAttributeCount = s.droppedAttributes
+	if len(s.events.queue) > 0 {
+		sd.events = s.events.copy()
+		sd.droppedEventCount = s.events.droppedCount
+	}
+	if len(s.links.queue) > 0 {
+		sd.links = s.links.copy()
+		sd.droppedLinkCount = s.links.droppedCount
+	}
+	return &sd
+}
+
+func (s *recordingSpan) addChild() {
+	if s == nil {
+		return
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.isRecording() {
+		return
+	}
+	s.childSpanCount++
+}
+
+func (*recordingSpan) private() {}
+
+// runtimeTrace starts a "runtime/trace".Task for the span and returns a
+// context containing the task.
+func (s *recordingSpan) runtimeTrace(ctx context.Context) context.Context {
+	if !rt.IsEnabled() {
+		// Avoid additional overhead if runtime/trace is not enabled.
+		return ctx
+	}
+	nctx, task := rt.NewTask(ctx, s.name)
+
+	s.mu.Lock()
+	s.executionTracerTaskEnd = task.End
+	s.mu.Unlock()
+
+	return nctx
+}
+
+// nonRecordingSpan is a minimal implementation of the OpenTelemetry Span API
+// that wraps a SpanContext. It performs no operations other than to return
+// the wrapped SpanContext or TracerProvider that created it.
+type nonRecordingSpan struct {
+	embedded.Span
+
+	// tracer is the SDK tracer that created this span.
+	tracer *tracer
+	sc     trace.SpanContext
+}
+
+var _ trace.Span = nonRecordingSpan{}
+
+// SpanContext returns the wrapped SpanContext.
+func (s nonRecordingSpan) SpanContext() trace.SpanContext { return s.sc }
+
+// IsRecording always returns false.
+func (nonRecordingSpan) IsRecording() bool { return false }
+
+// SetStatus does nothing.
+func (nonRecordingSpan) SetStatus(codes.Code, string) {}
+
+// SetError does nothing.
+func (nonRecordingSpan) SetError(bool) {}
+
+// SetAttributes does nothing.
+func (nonRecordingSpan) SetAttributes(...attribute.KeyValue) {}
+
+// End does nothing.
+func (nonRecordingSpan) End(...trace.SpanEndOption) {}
+
+// RecordError does nothing.
+func (nonRecordingSpan) RecordError(error, ...trace.EventOption) {}
+
+// AddEvent does nothing.
+func (nonRecordingSpan) AddEvent(string, ...trace.EventOption) {}
+
+// AddLink does nothing.
+func (nonRecordingSpan) AddLink(trace.Link) {}
+
+// SetName does nothing.
+func (nonRecordingSpan) SetName(string) {}
+
+// TracerProvider returns the trace.TracerProvider that provided the Tracer
+// that created this span.
+func (s nonRecordingSpan) TracerProvider() trace.TracerProvider { return s.tracer.provider }
+
+func isRecording(s SamplingResult) bool {
+	return s.Decision == RecordOnly || s.Decision == RecordAndSample
+}
+
+func isSampled(s SamplingResult) bool {
+	return s.Decision == RecordAndSample
+}
+
+// Status is the classified state of a Span.
+type Status struct {
+	// Code is an identifier of a Spans state classification.
+	Code codes.Code
+	// Description is a user hint about why that status was set. It is only
+	// applicable when Code is Error.
+	Description string
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/span_exporter.go

@@ -0,0 +1,36 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import "context"
+
+// SpanExporter handles the delivery of spans to external receivers. This is
+// the final component in the trace export pipeline.
+type SpanExporter interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// ExportSpans exports a batch of spans.
+	//
+	// This function is called synchronously, so there is no concurrency
+	// safety requirement. However, due to the synchronous calling pattern,
+	// it is critical that all timeouts and cancellations contained in the
+	// passed context must be honored.
+	//
+	// Any retry logic must be contained in this function. The SDK that
+	// calls this function will not implement any retry logic. All errors
+	// returned by this function are considered unrecoverable and will be
+	// reported to a configured error Handler.
+	ExportSpans(ctx context.Context, spans []ReadOnlySpan) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Shutdown notifies the exporter of a pending halt to operations. The
+	// exporter is expected to perform any cleanup or synchronization it
+	// requires while honoring all timeouts and cancellations contained in
+	// the passed context.
+	Shutdown(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/span_limits.go

@@ -0,0 +1,114 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import "go.opentelemetry.io/otel/sdk/internal/env"
+
+const (
+	// DefaultAttributeValueLengthLimit is the default maximum allowed
+	// attribute value length, unlimited.
+	DefaultAttributeValueLengthLimit = -1
+
+	// DefaultAttributeCountLimit is the default maximum number of attributes
+	// a span can have.
+	DefaultAttributeCountLimit = 128
+
+	// DefaultEventCountLimit is the default maximum number of events a span
+	// can have.
+	DefaultEventCountLimit = 128
+
+	// DefaultLinkCountLimit is the default maximum number of links a span can
+	// have.
+	DefaultLinkCountLimit = 128
+
+	// DefaultAttributePerEventCountLimit is the default maximum number of
+	// attributes a span event can have.
+	DefaultAttributePerEventCountLimit = 128
+
+	// DefaultAttributePerLinkCountLimit is the default maximum number of
+	// attributes a span link can have.
+	DefaultAttributePerLinkCountLimit = 128
+)
+
+// SpanLimits represents the limits of a span.
+type SpanLimits struct {
+	// AttributeValueLengthLimit is the maximum allowed attribute value length.
+	//
+	// This limit only applies to string and string slice attribute values.
+	// Any string longer than this value will be truncated to this length.
+	//
+	// Setting this to a negative value means no limit is applied.
+	AttributeValueLengthLimit int
+
+	// AttributeCountLimit is the maximum allowed span attribute count. Any
+	// attribute added to a span once this limit is reached will be dropped.
+	//
+	// Setting this to zero means no attributes will be recorded.
+	//
+	// Setting this to a negative value means no limit is applied.
+	AttributeCountLimit int
+
+	// EventCountLimit is the maximum allowed span event count. Any event
+	// added to a span once this limit is reached means it will be added but
+	// the oldest event will be dropped.
+	//
+	// Setting this to zero means no events we be recorded.
+	//
+	// Setting this to a negative value means no limit is applied.
+	EventCountLimit int
+
+	// LinkCountLimit is the maximum allowed span link count. Any link added
+	// to a span once this limit is reached means it will be added but the
+	// oldest link will be dropped.
+	//
+	// Setting this to zero means no links we be recorded.
+	//
+	// Setting this to a negative value means no limit is applied.
+	LinkCountLimit int
+
+	// AttributePerEventCountLimit is the maximum number of attributes allowed
+	// per span event. Any attribute added after this limit reached will be
+	// dropped.
+	//
+	// Setting this to zero means no attributes will be recorded for events.
+	//
+	// Setting this to a negative value means no limit is applied.
+	AttributePerEventCountLimit int
+
+	// AttributePerLinkCountLimit is the maximum number of attributes allowed
+	// per span link. Any attribute added after this limit reached will be
+	// dropped.
+	//
+	// Setting this to zero means no attributes will be recorded for links.
+	//
+	// Setting this to a negative value means no limit is applied.
+	AttributePerLinkCountLimit int
+}
+
+// NewSpanLimits returns a SpanLimits with all limits set to the value their
+// corresponding environment variable holds, or the default if unset.
+//
+// • AttributeValueLengthLimit: OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT
+// (default: unlimited)
+//
+// • AttributeCountLimit: OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT (default: 128)
+//
+// • EventCountLimit: OTEL_SPAN_EVENT_COUNT_LIMIT (default: 128)
+//
+// • AttributePerEventCountLimit: OTEL_EVENT_ATTRIBUTE_COUNT_LIMIT (default:
+// 128)
+//
+// • LinkCountLimit: OTEL_SPAN_LINK_COUNT_LIMIT (default: 128)
+//
+// • AttributePerLinkCountLimit: OTEL_LINK_ATTRIBUTE_COUNT_LIMIT (default: 128)
+func NewSpanLimits() SpanLimits {
+	return SpanLimits{
+		AttributeValueLengthLimit:   env.SpanAttributeValueLength(DefaultAttributeValueLengthLimit),
+		AttributeCountLimit:         env.SpanAttributeCount(DefaultAttributeCountLimit),
+		EventCountLimit:             env.SpanEventCount(DefaultEventCountLimit),
+		LinkCountLimit:              env.SpanLinkCount(DefaultLinkCountLimit),
+		AttributePerEventCountLimit: env.SpanEventAttributeCount(DefaultAttributePerEventCountLimit),
+		AttributePerLinkCountLimit:  env.SpanLinkAttributeCount(DefaultAttributePerLinkCountLimit),
+	}
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/span_processor.go

@@ -0,0 +1,61 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"sync"
+)
+
+// SpanProcessor is a processing pipeline for spans in the trace signal.
+// SpanProcessors registered with a TracerProvider and are called at the start
+// and end of a Span's lifecycle, and are called in the order they are
+// registered.
+type SpanProcessor interface {
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// OnStart is called when a span is started. It is called synchronously
+	// and should not block.
+	OnStart(parent context.Context, s ReadWriteSpan)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// OnEnd is called when span is finished. It is called synchronously and
+	// hence not block.
+	OnEnd(s ReadOnlySpan)
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// Shutdown is called when the SDK shuts down. Any cleanup or release of
+	// resources held by the processor should be done in this call.
+	//
+	// Calls to OnStart, OnEnd, or ForceFlush after this has been called
+	// should be ignored.
+	//
+	// All timeouts and cancellations contained in ctx must be honored, this
+	// should not block indefinitely.
+	Shutdown(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+
+	// ForceFlush exports all ended spans to the configured Exporter that have not yet
+	// been exported.  It should only be called when absolutely necessary, such as when
+	// using a FaaS provider that may suspend the process after an invocation, but before
+	// the Processor can export the completed spans.
+	ForceFlush(ctx context.Context) error
+	// DO NOT CHANGE: any modification will not be backwards compatible and
+	// must never be done outside of a new major release.
+}
+
+type spanProcessorState struct {
+	sp    SpanProcessor
+	state sync.Once
+}
+
+func newSpanProcessorState(sp SpanProcessor) *spanProcessorState {
+	return &spanProcessorState{sp: sp}
+}
+
+type spanProcessorStates []*spanProcessorState

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/tracer.go

@@ -0,0 +1,153 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+import (
+	"context"
+	"time"
+
+	"go.opentelemetry.io/otel/sdk/instrumentation"
+	"go.opentelemetry.io/otel/trace"
+	"go.opentelemetry.io/otel/trace/embedded"
+)
+
+type tracer struct {
+	embedded.Tracer
+
+	provider             *TracerProvider
+	instrumentationScope instrumentation.Scope
+}
+
+var _ trace.Tracer = &tracer{}
+
+// Start starts a Span and returns it along with a context containing it.
+//
+// The Span is created with the provided name and as a child of any existing
+// span context found in the passed context. The created Span will be
+// configured appropriately by any SpanOption passed.
+func (tr *tracer) Start(ctx context.Context, name string, options ...trace.SpanStartOption) (context.Context, trace.Span) {
+	config := trace.NewSpanStartConfig(options...)
+
+	if ctx == nil {
+		// Prevent trace.ContextWithSpan from panicking.
+		ctx = context.Background()
+	}
+
+	// For local spans created by this SDK, track child span count.
+	if p := trace.SpanFromContext(ctx); p != nil {
+		if sdkSpan, ok := p.(*recordingSpan); ok {
+			sdkSpan.addChild()
+		}
+	}
+
+	s := tr.newSpan(ctx, name, &config)
+	if rw, ok := s.(ReadWriteSpan); ok && s.IsRecording() {
+		sps := tr.provider.getSpanProcessors()
+		for _, sp := range sps {
+			sp.sp.OnStart(ctx, rw)
+		}
+	}
+	if rtt, ok := s.(runtimeTracer); ok {
+		ctx = rtt.runtimeTrace(ctx)
+	}
+
+	return trace.ContextWithSpan(ctx, s), s
+}
+
+type runtimeTracer interface {
+	// runtimeTrace starts a "runtime/trace".Task for the span and
+	// returns a context containing the task.
+	runtimeTrace(ctx context.Context) context.Context
+}
+
+// newSpan returns a new configured span.
+func (tr *tracer) newSpan(ctx context.Context, name string, config *trace.SpanConfig) trace.Span {
+	// If told explicitly to make this a new root use a zero value SpanContext
+	// as a parent which contains an invalid trace ID and is not remote.
+	var psc trace.SpanContext
+	if config.NewRoot() {
+		ctx = trace.ContextWithSpanContext(ctx, psc)
+	} else {
+		psc = trace.SpanContextFromContext(ctx)
+	}
+
+	// If there is a valid parent trace ID, use it to ensure the continuity of
+	// the trace. Always generate a new span ID so other components can rely
+	// on a unique span ID, even if the Span is non-recording.
+	var tid trace.TraceID
+	var sid trace.SpanID
+	if !psc.TraceID().IsValid() {
+		tid, sid = tr.provider.idGenerator.NewIDs(ctx)
+	} else {
+		tid = psc.TraceID()
+		sid = tr.provider.idGenerator.NewSpanID(ctx, tid)
+	}
+
+	samplingResult := tr.provider.sampler.ShouldSample(SamplingParameters{
+		ParentContext: ctx,
+		TraceID:       tid,
+		Name:          name,
+		Kind:          config.SpanKind(),
+		Attributes:    config.Attributes(),
+		Links:         config.Links(),
+	})
+
+	scc := trace.SpanContextConfig{
+		TraceID:    tid,
+		SpanID:     sid,
+		TraceState: samplingResult.Tracestate,
+	}
+	if isSampled(samplingResult) {
+		scc.TraceFlags = psc.TraceFlags() | trace.FlagsSampled
+	} else {
+		scc.TraceFlags = psc.TraceFlags() &^ trace.FlagsSampled
+	}
+	sc := trace.NewSpanContext(scc)
+
+	if !isRecording(samplingResult) {
+		return tr.newNonRecordingSpan(sc)
+	}
+	return tr.newRecordingSpan(psc, sc, name, samplingResult, config)
+}
+
+// newRecordingSpan returns a new configured recordingSpan.
+func (tr *tracer) newRecordingSpan(psc, sc trace.SpanContext, name string, sr SamplingResult, config *trace.SpanConfig) *recordingSpan {
+	startTime := config.Timestamp()
+	if startTime.IsZero() {
+		startTime = time.Now()
+	}
+
+	s := &recordingSpan{
+		// Do not pre-allocate the attributes slice here! Doing so will
+		// allocate memory that is likely never going to be used, or if used,
+		// will be over-sized. The default Go compiler has been tested to
+		// dynamically allocate needed space very well. Benchmarking has shown
+		// it to be more performant than what we can predetermine here,
+		// especially for the common use case of few to no added
+		// attributes.
+
+		parent:      psc,
+		spanContext: sc,
+		spanKind:    trace.ValidateSpanKind(config.SpanKind()),
+		name:        name,
+		startTime:   startTime,
+		events:      newEvictedQueueEvent(tr.provider.spanLimits.EventCountLimit),
+		links:       newEvictedQueueLink(tr.provider.spanLimits.LinkCountLimit),
+		tracer:      tr,
+	}
+
+	for _, l := range config.Links() {
+		s.AddLink(l)
+	}
+
+	s.SetAttributes(sr.Attributes...)
+	s.SetAttributes(config.Attributes()...)
+
+	return s
+}
+
+// newNonRecordingSpan returns a new configured nonRecordingSpan.
+func (tr *tracer) newNonRecordingSpan(sc trace.SpanContext) nonRecordingSpan {
+	return nonRecordingSpan{tracer: tr, sc: sc}
+}

e2e/vendor/go.opentelemetry.io/otel/sdk/trace/version.go

@@ -0,0 +1,9 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace // import "go.opentelemetry.io/otel/sdk/trace"
+
+// version is the current release version of the metric SDK in use.
+func version() string {
+	return "1.16.0-rc.1"
+}