traceutil

Documentation

Overview

Package traceutil contains functions for extracting and processing traces. It should only import payload and nothing else.

Index

• Constants
• Variables
• func ChildrenMap(t pb.Trace) map[uint64][]*pb.Span
• func ComputeTopLevel(trace pb.Trace)
• func GetAppServicesTags() map[string]string
• func GetEnv(root *pb.Span, t *pb.TraceChunk) string
• func GetMeta(s *pb.Span, key string) (string, bool)
• func GetMetaDefault(s *pb.Span, key, fallback string) string
• func GetMetaStruct(s *pb.Span, key string) (interface{}, bool)
• func GetMetric(s *pb.Span, key string) (float64, bool)
• func GetRoot(t pb.Trace) *pb.Span
• func HasTopLevel(s *pb.Span) bool
• func IsMeasured(s *pb.Span) bool
• func IsPartialSnapshot(s *pb.Span) bool
• func NormalizeName(name string) (string, error)
• func NormalizePeerService(svc string) (string, error)
• func NormalizeService(svc string, lang string) (string, error)
• func NormalizeTag(v string) string
• func NormalizeTagValue(v string) string
• func SetMeasured(s *pb.Span, measured bool)
• func SetMeta(s *pb.Span, key, val string)
• func SetMetaStruct(s *pb.Span, key string, val interface{}) error
• func SetMetric(s *pb.Span, key string, val float64)
• func SetTopLevel(s *pb.Span, topLevel bool)
• func TruncateUTF8(s string, limit int) string
• func UpdateTracerTopLevel(s *pb.Span)
• type ProcessedTrace
  • func (pt *ProcessedTrace) Clone() *ProcessedTrace

Constants

const (
	// DefaultSpanName is the default name we assign a span if it's missing and we have no reasonable fallback
	DefaultSpanName = "unnamed_operation"
	// DefaultServiceName is the default name we assign a service if it's missing and we have no reasonable fallback
	DefaultServiceName = "unnamed-service"
)

const (
	// MaxNameLen the maximum length a name can have
	MaxNameLen = 100
	// MaxServiceLen the maximum length a service can have
	MaxServiceLen = 100
)

Variables

var (
	// ErrEmpty specifies that the passed input was empty.
	ErrEmpty = errors.New("empty")
	// ErrTooLong signifies that the input was too long.
	ErrTooLong = errors.New("too long")
	// ErrInvalid signifies that the input was invalid.
	ErrInvalid = errors.New("invalid")
)

Functions

func ChildrenMap

func ChildrenMap(t pb.Trace) map[uint64][]*pb.Span

ChildrenMap returns a map containing for each span id the list of its direct children.

func ComputeTopLevel

func ComputeTopLevel(trace pb.Trace)

ComputeTopLevel updates all the spans top-level attribute.

A span is considered top-level if:

• it's a root span
• OR its parent is unknown (other part of the code, distributed trace)
• OR its parent belongs to another service (in that case it's a "local root" being the highest ancestor of other spans belonging to this service and attached to it).

func GetAppServicesTags

func GetAppServicesTags() map[string]string

GetAppServicesTags returns the env vars pulled from the Azure App Service instance. In some cases we will need to add extra tags for function apps.

func GetEnv

func GetEnv(root *pb.Span, t *pb.TraceChunk) string

GetEnv returns the first "env" tag found in trace t. Search starts by root

func GetMeta

func GetMeta(s *pb.Span, key string) (string, bool)

GetMeta gets the metadata value in the span Meta map.

func GetMetaDefault

func GetMetaDefault(s *pb.Span, key, fallback string) string

GetMetaDefault gets the metadata value in the span Meta map and fallbacks to fallback.

func GetMetaStruct

func GetMetaStruct(s *pb.Span, key string) (interface{}, bool)

GetMetaStruct gets the structured metadata value in the span MetaStruct map.

func GetMetric

func GetMetric(s *pb.Span, key string) (float64, bool)

GetMetric gets the metadata value in the span Metrics map.

func GetRoot

func GetRoot(t pb.Trace) *pb.Span

GetRoot extracts the root span from a trace

func HasTopLevel

func HasTopLevel(s *pb.Span) bool

HasTopLevel returns true if span is top-level.

func IsMeasured

func IsMeasured(s *pb.Span) bool

IsMeasured returns true if a span should be measured (i.e., it should get trace metrics calculated).

func IsPartialSnapshot

func IsPartialSnapshot(s *pb.Span) bool

IsPartialSnapshot returns true if the span is a partial snapshot. This kind of spans are partial images of long-running spans. When incomplete, a partial snapshot has a metric _dd.partial_version which is a positive integer. The metric usually increases each time a new version of the same span is sent by the tracer

func NormalizeName

func NormalizeName(name string) (string, error)

NormalizeName normalizes a span name and returns an error describing the reason (if any) why the name was modified.

func NormalizePeerService

func NormalizePeerService(svc string) (string, error)

NormalizePeerService normalizes a span's peer.service and returns an error describing the reason (if any) why the name was modified.

func NormalizeService

func NormalizeService(svc string, lang string) (string, error)

NormalizeService normalizes a span service and returns an error describing the reason (if any) why the name was modified.

func NormalizeTag

func NormalizeTag(v string) string

NormalizeTag applies some normalization to ensure the full tag_key:tag_value string matches the backend requirements.

func NormalizeTagValue

func NormalizeTagValue(v string) string

NormalizeTagValue applies some normalization to ensure the tag value matches the backend requirements. It should be used for cases where we have just the tag_value as the input (instead of tag_key:tag_value).

func SetMeasured

func SetMeasured(s *pb.Span, measured bool)

SetMeasured sets the measured attribute of the span.

func SetMeta

func SetMeta(s *pb.Span, key, val string)

SetMeta sets the metadata at key to the val on the span s.

func SetMetaStruct

func SetMetaStruct(s *pb.Span, key string, val interface{}) error

SetMetaStruct sets the structured metadata at key to the val on the span s.

func SetMetric

func SetMetric(s *pb.Span, key string, val float64)

SetMetric sets the metric at key to the val on the span s.

func SetTopLevel

func SetTopLevel(s *pb.Span, topLevel bool)

SetTopLevel sets the top-level attribute of the span.

func TruncateUTF8

func TruncateUTF8(s string, limit int) string

TruncateUTF8 truncates the given string to make sure it uses less than limit bytes. If the last character is an utf8 character that would be splitten, it removes it entirely to make sure the resulting string is not broken.

func UpdateTracerTopLevel

func UpdateTracerTopLevel(s *pb.Span)

UpdateTracerTopLevel sets _top_level tag on spans flagged by the tracer

Types

type ProcessedTrace

type ProcessedTrace struct {
	TraceChunk             *pb.TraceChunk
	Root                   *pb.Span
	TracerEnv              string
	AppVersion             string
	TracerHostname         string
	ClientDroppedP0sWeight float64
	GitCommitSha           string
	ImageTag               string
}

ProcessedTrace represents a trace being processed in the agent.

func (*ProcessedTrace) Clone

func (pt *ProcessedTrace) Clone() *ProcessedTrace

Clone creates a copy of ProcessedTrace, cloning p, p.TraceChunk, and p.Root. This means it is safe to modify the returned ProcessedTrace's (pt's) fields along with fields in pt.TraceChunk and fields in pt.Root.

The most important consequence of this is that the TraceChunk's Spans field can be assigned, *BUT* the Spans value itself should not be modified. i.e. This is ok:

pt2 := pt.Clone()
pt2.TraceChunk.Spans = make([]*pb.Span)

but this is NOT ok:

pt2 := pt.Clone()
pt2.TraceChunk.Spans[0] = &pb.Span{} // This will be visible in pt.