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

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2023-05-09 17:19:48 +00:00
// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package trace // import "go.opentelemetry.io/otel/sdk/trace"
import (
"context"
"fmt"
"reflect"
"runtime"
rt "runtime/trace"
"strings"
"sync"
"time"
"unicode/utf8"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/codes"
"go.opentelemetry.io/otel/sdk/instrumentation"
"go.opentelemetry.io/otel/sdk/internal"
"go.opentelemetry.io/otel/sdk/resource"
semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
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"go.opentelemetry.io/otel/trace"
)
// 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
// 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 {
// 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
// events are stored in FIFO queue capped by configured limit.
events evictedQueue
// links are stored in FIFO queue capped by configured limit.
links evictedQueue
// executionTracerTaskEnd ends the execution tracer span.
executionTracerTaskEnd func()
// tracer is the SDK tracer that created this span.
tracer *tracer
}
var _ ReadWriteSpan = (*recordingSpan)(nil)
var _ 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.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.IsRecording() {
return
}
s.mu.Lock()
defer s.mu.Unlock()
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.IsRecording() {
return
}
s.mu.Lock()
defer s.mu.Unlock()
limit := s.tracer.provider.spanLimits.AttributeCountLimit
if limit == 0 {
// No attributes allowed.
s.droppedAttributes += 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.
for _, a := range attributes {
if !a.Valid() {
// Drop all invalid attributes.
s.droppedAttributes++
continue
}
a = truncateAttr(s.tracer.provider.spanLimits.AttributeValueLengthLimit, a)
s.attributes = append(s.attributes, a)
}
}
// 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)
s.dedupeAttrsFromRecord(&exists)
// Now that s.attributes is deduplicated, adding unique attributes up to
// the capacity of s will not over allocate s.attributes.
for _, a := range attrs {
if !a.Valid() {
// Drop all invalid attributes.
s.droppedAttributes++
continue
}
if idx, ok := exists[a.Key]; ok {
// Perform all updates before dropping, even when at capacity.
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.droppedAttributes++
} 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.
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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 := internal.MonotonicEndTime(s.startTime)
// Do relative expensive check now that we have an end time and see if we
// need to do any more processing.
if !s.IsRecording() {
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.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()
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if len(sps) == 0 {
return
}
snap := s.snapshot()
for _, sp := range sps {
sp.sp.OnEnd(snap)
}
}
// 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 || !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 than this method does nothing.
func (s *recordingSpan) AddEvent(name string, o ...trace.EventOption) {
if !s.IsRecording() {
return
}
s.addEvent(name, o...)
}
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.mu.Lock()
s.events.add(e)
s.mu.Unlock()
}
// 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.IsRecording() {
return
}
s.mu.Lock()
defer s.mu.Unlock()
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)
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
}
}
// s.attributes have element types of attribute.KeyValue. These types are
// not pointers and they themselves do not contain pointer fields,
// therefore the duplicate values do not need to be zeroed for them to be
// garbage collected.
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.interfaceArrayToLinksArray()
}
// 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.interfaceArrayToEventArray()
}
// 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 {
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.IsRecording() || !link.SpanContext.IsValid() {
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.mu.Lock()
s.links.add(l)
s.mu.Unlock()
}
// 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.interfaceArrayToEventArray()
sd.droppedEventCount = s.events.droppedCount
}
if len(s.links.queue) > 0 {
sd.links = s.interfaceArrayToLinksArray()
sd.droppedLinkCount = s.links.droppedCount
}
return &sd
}
func (s *recordingSpan) interfaceArrayToLinksArray() []Link {
linkArr := make([]Link, 0)
for _, value := range s.links.queue {
linkArr = append(linkArr, value.(Link))
}
return linkArr
}
func (s *recordingSpan) interfaceArrayToEventArray() []Event {
eventArr := make([]Event, 0)
for _, value := range s.events.queue {
eventArr = append(eventArr, value.(Event))
}
return eventArr
}
func (s *recordingSpan) addChild() {
if !s.IsRecording() {
return
}
s.mu.Lock()
s.childSpanCount++
s.mu.Unlock()
}
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 {
// 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) {}
// 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
}