package propagators

import "go.opentelemetry.io/otel/api/propagators"

Package propagators contains interface definition for BinaryFormat and TextFormat propagators and implementation of propagators for different format and suppliers.

Index ¶

• Constants
• type B3
• func (b3 B3) Extract(ctx context.Context, supplier Supplier) (core.SpanContext, dctx.Map)
• func (b3 B3) GetAllKeys() []string
• func (b3 B3) Inject(ctx context.Context, supplier Supplier)
• type BinaryFormat
• func Binary() BinaryFormat
• type NoopTextFormat
• func (np NoopTextFormat) Extract(ctx context.Context, supplier Supplier) (core.SpanContext, dctx.Map)
• func (np NoopTextFormat) GetAllKeys() []string
• func (np NoopTextFormat) Inject(ctx context.Context, supplier Supplier)
• type Supplier
• type TextFormat
• type TraceContext
• func (hp TraceContext) Extract( ctx context.Context, supplier Supplier, ) (core.SpanContext, dctx.Map)
• func (hp TraceContext) GetAllKeys() []string
• func (hp TraceContext) Inject(ctx context.Context, supplier Supplier)

Constants ¶

const (
	B3SingleHeader       = "X-B3"
	B3DebugFlagHeader    = "X-B3-Flags"
	B3TraceIDHeader      = "X-B3-TraceId"
	B3SpanIDHeader       = "X-B3-SpanId"
	B3SampledHeader      = "X-B3-Sampled"
	B3ParentSpanIDHeader = "X-B3-ParentSpanId"
)

const (
	TraceparentHeader        = "Traceparent"
	CorrelationContextHeader = "Correlation-Context"
)

Types ¶

type B3 ¶

type B3 struct {
	SingleHeader bool
}

B3 propagator serializes core.SpanContext to/from B3 Headers. This propagator supports both version of B3 headers,

1. Single Header : X-B3: {TraceId}-{SpanId}-{SamplingState}-{ParentSpanId}
2. Multiple Headers: X-B3-TraceId: {TraceId} X-B3-ParentSpanId: {ParentSpanId} X-B3-SpanId: {SpanId} X-B3-Sampled: {SamplingState} X-B3-Flags: {DebugFlag}

If SingleHeader is set to true then X-B3 header is used to inject and extract. Otherwise, separate headers are used to inject and extract.

func (B3) Extract ¶

func (b3 B3) Extract(ctx context.Context, supplier Supplier) (core.SpanContext, dctx.Map)

Extract retrieves B3 Headers from the supplier

func (B3) GetAllKeys ¶

func (b3 B3) GetAllKeys() []string

func (B3) Inject ¶

func (b3 B3) Inject(ctx context.Context, supplier Supplier)

type BinaryFormat ¶

type BinaryFormat interface {
	// ToBytes serializes span context into a byte array and returns the array.
	ToBytes(sc core.SpanContext) []byte

	// FromBytes de-serializes byte array into span context and returns the span context.
	FromBytes([]byte) core.SpanContext
}

BinaryFormat is an interface that specifies methods to convert SpanContext to/from byte array.

func Binary ¶

func Binary() BinaryFormat

Binary creates a new propagator. The propagator implements ToBytes and FromBytes method to transform SpanContext to/from byte array.

type NoopTextFormat ¶

type NoopTextFormat struct{}

NoopTextFormat implements TextFormat that does nothing.

func (NoopTextFormat) Extract ¶

func (np NoopTextFormat) Extract(ctx context.Context, supplier Supplier) (core.SpanContext, dctx.Map)

Extract does nothing and returns an empty SpanContext

func (NoopTextFormat) GetAllKeys ¶

func (np NoopTextFormat) GetAllKeys() []string

GetAllKeys returns empty list of strings.

func (NoopTextFormat) Inject ¶

func (np NoopTextFormat) Inject(ctx context.Context, supplier Supplier)

Inject does nothing.

type Supplier ¶

type Supplier interface {
	Get(key string) string
	Set(key string, value string)
}

Supplier is an interface that specifies methods to retrieve and store value for a key to an associated carrier. Get method retrieves the value for a given key. Set method stores the value for a given key.

type TextFormat ¶

type TextFormat interface {
	// Inject method retrieves current SpanContext from the ctx, encodes it into propagator
	// specific format and then injects the encoded SpanContext using supplier into a carrier
	// associated with the supplier. It also takes a correlationCtx whose values will be
	// injected into a carrier using the supplier.
	Inject(ctx context.Context, supplier Supplier)

	// Extract method retrieves encoded SpanContext using supplier from the associated carrier.
	// It decodes the SpanContext and returns it and a dctx of correlated context.
	// If no SpanContext was retrieved OR if the retrieved SpanContext is invalid then
	// an empty SpanContext is returned.
	Extract(ctx context.Context, supplier Supplier) (core.SpanContext, dctx.Map)

	// GetAllKeys returns all the keys that this propagator injects/extracts into/from a
	// carrier. The use cases for this are
	// * allow pre-allocation of fields, especially in systems like gRPC Metadata
	// * allow a single-pass over an iterator (ex OpenTracing has no getter in TextMap)
	GetAllKeys() []string
}

TextFormat is an interface that specifies methods to inject and extract SpanContext and distributed context into/from a carrier using Supplier interface. For example, HTTP Trace Context propagator would encode SpanContext into W3C Trace Context Header and set the header into HttpRequest.

type TraceContext ¶

type TraceContext struct{}

TraceContext propagates SpanContext in W3C TraceContext format.

func (TraceContext) Extract ¶

func (hp TraceContext) Extract(
	ctx context.Context, supplier Supplier,
) (core.SpanContext, dctx.Map)

func (TraceContext) GetAllKeys ¶

func (hp TraceContext) GetAllKeys() []string

func (TraceContext) Inject ¶

func (hp TraceContext) Inject(ctx context.Context, supplier Supplier)

Source Files ¶

b3_propagator.go binary_propagator.go doc.go text_noop_propagator.go text_propagator.go trace_context_propagator.go