Struct TextMapSplitPropagator

pub struct TextMapSplitPropagator { /* private fields */ }

A text map propagator that uses different propagators for injection and extraction.

This propagator allows for asymmetric context propagation where different propagation strategies can be used for outgoing requests (injection) versus incoming requests (extraction). This is useful when you need to maintain compatibility with multiple tracing systems or protocols.

Use Cases

• Migrating between tracing systems while maintaining compatibility
• Supporting multiple trace context formats in a single service
• Using environment-specific propagation strategies

Implementations

impl TextMapSplitPropagator

pub fn new( extract_propagator: Propagator, inject_propagator: Propagator, ) -> Self

Creates a new split propagator with separate propagators for extraction and injection.

Arguments

• extract_propagator: Propagator used for extracting context from incoming requests
• inject_propagator: Propagator used for injecting context into outgoing requests

Returns

A new TextMapSplitPropagator instance

pub fn from_env() -> Result<Self, TraceError>

Creates a split propagator based on the OTEL_PROPAGATORS environment variable.

This method reads the OTEL_PROPAGATORS environment variable to determine which propagators to use. The first propagator in the list is used for injection, while all propagators are composed together for extraction.

Environment Variable Format

The OTEL_PROPAGATORS variable should contain a comma-separated list of propagator names:

• tracecontext: W3C Trace Context propagator
• baggage: W3C Baggage propagator
• b3: B3 single header propagator (requires “zipkin” feature)
• b3multi: B3 multiple header propagator (requires “zipkin” feature)
• none: No-op propagator

Returns

A configured TextMapSplitPropagator on success, or a TraceError if the environment variable contains unsupported propagator names.

Examples

export OTEL_PROPAGATORS=tracecontext,baggage

use telemetry_rust::propagation::TextMapSplitPropagator;

let propagator = TextMapSplitPropagator::from_env()?;

Trait Implementations

impl Debug for TextMapSplitPropagator

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

Formats the value using the given formatter.

impl Default for TextMapSplitPropagator

fn default() -> Self

Returns the “default value” for a type.

impl TextMapPropagator for TextMapSplitPropagator

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

Properly 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 data using the provided Extractor. If no data for this format was retrieved OR if the retrieved data is invalid, then the given 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.