sampling

Documentation

Overview

Package sampling contains the interfaces and data types used to implement the various sampling policies.

Index

• type Decision
• type PolicyEvaluator
  • func NewAlwaysSample(logger *zap.Logger) PolicyEvaluator
  • func NewNumericAttributeFilter(logger *zap.Logger, key string, minValue, maxValue int64) PolicyEvaluator
  • func NewRateLimiting(logger *zap.Logger, spansPerSecond int64) PolicyEvaluator
  • func NewStringAttributeFilter(logger *zap.Logger, key string, values []string) PolicyEvaluator
• type TraceData

Types

type Decision

type Decision int32

Decision gives the status of sampling decision.

const (
	// Unspecified indicates that the status of the decision was not set yet.
	Unspecified Decision = iota
	// Pending indicates that the policy was not evaluated yet.
	Pending
	// Sampled is used to indicate that the decision was already taken
	// to sample the data.
	Sampled
	// NotSampled is used to indicate that the decision was already taken
	// to not sample the data.
	NotSampled
	// Dropped is used when data needs to be purged before the sampling policy
	// had a chance to evaluate it.
	Dropped
)

type PolicyEvaluator

type PolicyEvaluator interface {
	// OnLateArrivingSpans notifies the evaluator that the given list of spans arrived
	// after the sampling decision was already taken for the trace.
	// This gives the evaluator a chance to log any message/metrics and/or update any
	// related internal state.
	OnLateArrivingSpans(earlyDecision Decision, spans []*tracepb.Span) error

	// Evaluate looks at the trace data and returns a corresponding SamplingDecision.
	Evaluate(traceID []byte, trace *TraceData) (Decision, error)

	// OnDroppedSpans is called when the trace needs to be dropped, due to memory
	// pressure, before the decision_wait time has been reached.
	OnDroppedSpans(traceID []byte, trace *TraceData) (Decision, error)
}

PolicyEvaluator implements a tail-based sampling policy evaluator, which makes a sampling decision for a given trace when requested.

func NewAlwaysSample

func NewAlwaysSample(logger *zap.Logger) PolicyEvaluator

NewAlwaysSample creates a policy evaluator the samples all traces.

func NewNumericAttributeFilter

func NewNumericAttributeFilter(logger *zap.Logger, key string, minValue, maxValue int64) PolicyEvaluator

NewNumericAttributeFilter creates a policy evaluator that samples all traces with the given attribute in the given numeric range.

func NewRateLimiting

func NewRateLimiting(logger *zap.Logger, spansPerSecond int64) PolicyEvaluator

NewRateLimiting creates a policy evaluator the samples all traces.

func NewStringAttributeFilter

func NewStringAttributeFilter(logger *zap.Logger, key string, values []string) PolicyEvaluator

NewStringAttributeFilter creates a policy evaluator that samples all traces with the given attribute in the given numeric range.

type TraceData

type TraceData struct {
	sync.Mutex
	// Decisions gives the current status of the sampling decision for each policy.
	Decisions []Decision
	// Arrival time the first span for the trace was received.
	ArrivalTime time.Time
	// Decisiontime time when sampling decision was taken.
	DecisionTime time.Time
	// SpanCount track the number of spans on the trace.
	SpanCount int64
	// ReceivedBatches stores all the batches received for the trace.
	ReceivedBatches []consumerdata.TraceData
}

TraceData stores the sampling related trace data.