README
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Propagation
Documentation
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Overview ¶
Package propagation contains OpenTelemetry context propagators.
OpenTelemetry propagators are used to extract and inject context data from and into messages exchanged by applications. The propagator supported by this package is the W3C Trace Context encoding (https://www.w3.org/TR/trace-context/), and W3C Baggage (https://www.w3.org/TR/baggage/).
Index ¶
Examples ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Baggage ¶ added in v0.14.0
type Baggage struct{}
Baggage is a propagator that supports the W3C Baggage format.
This propagates user-defined baggage associated with a trace. The complete specification is defined at https://www.w3.org/TR/baggage/.
func (Baggage) Extract ¶ added in v0.14.0
Extract returns a copy of parent with the baggage from the carrier added.
type HeaderCarrier ¶ added in v0.18.0
HeaderCarrier adapts http.Header to satisfy the TextMapCarrier interface.
func (HeaderCarrier) Get ¶ added in v0.18.0
func (hc HeaderCarrier) Get(key string) string
Get returns the value associated with the passed key.
func (HeaderCarrier) Keys ¶ added in v0.18.0
func (hc HeaderCarrier) Keys() []string
Keys lists the keys stored in this carrier.
func (HeaderCarrier) Set ¶ added in v0.18.0
func (hc HeaderCarrier) Set(key string, value string)
Set stores the key-value pair.
type MapCarrier ¶ added in v1.2.0
MapCarrier is a TextMapCarrier that uses a map held in memory as a storage medium for propagated key-value pairs.
func (MapCarrier) Get ¶ added in v1.2.0
func (c MapCarrier) Get(key string) string
Get returns the value associated with the passed key.
func (MapCarrier) Keys ¶ added in v1.2.0
func (c MapCarrier) Keys() []string
Keys lists the keys stored in this carrier.
func (MapCarrier) Set ¶ added in v1.2.0
func (c MapCarrier) Set(key, value string)
Set stores the key-value pair.
type TextMapCarrier ¶ added in v0.14.0
type TextMapCarrier interface {
// Get returns the value associated with the passed key.
Get(key string) string
// Set stores the key-value pair.
Set(key string, value string)
// Keys lists the keys stored in this carrier.
Keys() []string
}
TextMapCarrier is the storage medium used by a TextMapPropagator.
type TextMapPropagator ¶ added in v0.14.0
type TextMapPropagator interface {
// Inject set cross-cutting concerns from the Context into the carrier.
Inject(ctx context.Context, carrier TextMapCarrier)
// Extract reads cross-cutting concerns from the carrier into a Context.
Extract(ctx context.Context, carrier TextMapCarrier) context.Context
// Fields returns the keys whose values are set with Inject.
Fields() []string
}
TextMapPropagator propagates cross-cutting concerns as key-value text pairs within a carrier that travels in-band across process boundaries.
func NewCompositeTextMapPropagator ¶ added in v0.14.0
func NewCompositeTextMapPropagator(p ...TextMapPropagator) TextMapPropagator
NewCompositeTextMapPropagator returns a unified TextMapPropagator from the group of passed TextMapPropagator. This allows different cross-cutting concerns to be propagates in a unified manner.
The returned TextMapPropagator will inject and extract cross-cutting concerns in the order the TextMapPropagators were provided. Additionally, the Fields method will return a de-duplicated slice of the keys that are set with the Inject method.
type TraceContext ¶ added in v0.14.0
type TraceContext struct{}
TraceContext is a propagator that supports the W3C Trace Context format (https://www.w3.org/TR/trace-context/)
This propagator will propagate the traceparent and tracestate headers to guarantee traces are not broken. It is up to the users of this propagator to choose if they want to participate in a trace by modifying the traceparent header and relevant parts of the tracestate header containing their proprietary information.
Example ¶
package main
import (
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/propagation"
)
func main() {
tc := propagation.TraceContext{}
// Register the TraceContext propagator globally.
otel.SetTextMapPropagator(tc)
}
Output:
func (TraceContext) Extract ¶ added in v0.14.0
func (tc TraceContext) Extract(ctx context.Context, carrier TextMapCarrier) context.Context
Extract reads tracecontext from the carrier into a returned Context.
The returned Context will be a copy of ctx and contain the extracted tracecontext as the remote SpanContext. If the extracted tracecontext is invalid, the passed ctx will be returned directly instead.
func (TraceContext) Fields ¶ added in v0.14.0
func (tc TraceContext) Fields() []string
Fields returns the keys who's values are set with Inject.
func (TraceContext) Inject ¶ added in v0.14.0
func (tc TraceContext) Inject(ctx context.Context, carrier TextMapCarrier)
Inject set tracecontext from the Context into the carrier.
Source Files