Struct HeaderExtractor

pub struct HeaderExtractor<'a>(/* private fields */);

Extracts the TextMapPropagator to access trace parent information in HTTP headers.

This propagation is useful when an HTTP request already has a trace parent which can be picked up by the Tower Layer to link both spans together. A concrete usage example is available in SpanExt::from_request.

This is pretty much a copy-pasted version of the HeaderExtractor from the opentelemetry_http crate. However, we cannot use this crate, as it uses an outdated version of the underlying http crate.

Implementations

impl<'a> HeaderExtractor<'a>

pub fn new(headers: &'a HeaderMap) -> Self

Create a new header extractor from a reference to a [HeaderMap].

pub fn extract_context(&self) -> Context

Extracts the TextMapPropagator from the HTTP headers.

Trait Implementations

impl Extractor for HeaderExtractor<'_>

fn get(&self, key: &str) -> Option<&str>

Get a value from a key from the underlying data.

fn keys(&self) -> Vec<&str>

Collect all the keys from the underlying data.

fn get_all(&self, key: &str) -> Option<Vec<&str>>

Get all values from a key from the underlying data.