Struct BaggagePropagator

pub struct BaggagePropagator { /* private fields */ }

Propagates name-value pairs in W3C Baggage format.

Baggage is used to annotate telemetry, adding context and information to metrics, traces, and logs. It is an abstract data type represented by a set of name-value pairs describing user-defined properties. Each name in a Baggage is associated with exactly one value. Baggages are serialized according to the editor’s draft of the W3C Baggage specification.

Examples

use opentelemetry::{baggage::{Baggage, BaggageExt}, propagation::TextMapPropagator};
use opentelemetry_sdk::propagation::BaggagePropagator;
use std::collections::HashMap;

// Example baggage value passed in externally via http headers
let mut headers = HashMap::new();
headers.insert("baggage".to_string(), "user_id=1".to_string());

let propagator = BaggagePropagator::new();
// can extract from any type that impls `Extractor`, usually an HTTP header map
let cx = propagator.extract(&headers);

// Iterate over extracted name-value pairs
for (name, value) in cx.baggage() {
    // ...
}

// Add new baggage
let mut baggage = Baggage::new();
let _ = baggage.insert("server_id", "42");

let cx_with_additions = cx.with_baggage(baggage);

// Inject baggage into http request
propagator.inject_context(&cx_with_additions, &mut headers);

let header_value = headers.get("baggage").expect("header is injected");
assert!(!header_value.contains("user_id=1"), "still contains previous name-value");
assert!(header_value.contains("server_id=42"), "does not contain new name-value pair");

Implementations

impl BaggagePropagator

pub fn new() -> BaggagePropagator

Construct a new baggage propagator.

Trait Implementations

impl Debug for BaggagePropagator

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

Formats the value using the given formatter.

impl Default for BaggagePropagator

fn default() -> BaggagePropagator

Returns the “default value” for a type.

impl TextMapPropagator for BaggagePropagator

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

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

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

Extracts a Context with baggage values from a Extractor.

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.