Struct TextMapCompositePropagator

pub struct TextMapCompositePropagator { /* private fields */ }

Composite propagator for TextMapPropagators.

A propagator that chains multiple TextMapPropagator propagators together, injecting or extracting by their respective HTTP header names.

Injection and extraction from this propagator will preserve the order of the injectors and extractors passed in during initialization.

Examples

use opentelemetry::{
    baggage::BaggageExt,
    propagation::{TextMapPropagator, TextMapCompositePropagator},

    trace::{TraceContextExt, Tracer, TracerProvider},
    Context, KeyValue,
};
use opentelemetry_sdk::propagation::{
    BaggagePropagator, TraceContextPropagator,
};
use opentelemetry_sdk::trace as sdktrace;
use std::collections::HashMap;

// First create 1 or more propagators
let baggage_propagator = BaggagePropagator::new();
let trace_context_propagator = TraceContextPropagator::new();

// Then create a composite propagator
let composite_propagator = TextMapCompositePropagator::new(vec![
    Box::new(baggage_propagator),
    Box::new(trace_context_propagator),
]);

// Then for a given implementation of `Injector`
let mut injector = HashMap::new();

// And a given span
let example_span = sdktrace::TracerProvider::default()
    .tracer("example-component")
    .start("span-name");

// with the current context, call inject to add the headers
composite_propagator.inject_context(
    &Context::current_with_span(example_span)
        .with_baggage(vec![KeyValue::new("test", "example")]),
    &mut injector,
);

// The injector now has both `baggage` and `traceparent` headers
assert!(injector.get("baggage").is_some());
assert!(injector.get("traceparent").is_some());

Implementations

impl TextMapCompositePropagator

pub fn new(propagators: Vec<Box<dyn TextMapPropagator + Send + Sync>>) -> Self

Constructs a new propagator out of instances of TextMapPropagator.

Trait Implementations

impl Debug for TextMapCompositePropagator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl TextMapPropagator for TextMapCompositePropagator

fn inject_context(&self, context: &Context, injector: &mut dyn Injector)

Encodes the values of the Context and injects them into the Injector.

fn extract_with_context( &self, cx: &Context, extractor: &dyn Extractor, ) -> Context

Retrieves encoded Context information using the Extractor. If no data was retrieved OR if the retrieved data is invalid, then the current Context is returned.

fn fields(&self) -> FieldIter<'_>

Returns iter of fields used by TextMapPropagator

fn inject(&self, injector: &mut dyn Injector)

Properly encodes the values of the current Context and injects them into the Injector.

fn extract(&self, extractor: &dyn Extractor) -> Context

Retrieves encoded data using the provided Extractor. If no data for this format was retrieved OR if the retrieved data is invalid, then the current Context is returned.