Struct TracesConfig 

pub struct TracesConfig {
    pub enabled: bool,
    pub sample_ratio: f64,
    pub response_header: bool,
    pub capture_headers: Vec<String>,
    pub exclude_paths: Vec<String>,
}

Distributed traces: one span per request, children for the work inside it.

Fields

enabled: bool

Build spans at all. On (with [observability] enabled) even when no exporter is configured, because the request id and the error fields a span carries are worth having in the logs alone.

sample_ratio: f64

Fraction of root requests recorded, 0.0–1.0. This is head sampling — the decision is made before the request runs, so it cannot prefer the ones that will fail. Keeping every failure and a fraction of the rest is tail sampling, which is a Collector processor’s job, not this server’s: sample everything here and decide there.

A sampled trace is sampled whole — a child never disagrees with its parent — and an incoming traceparent decides for its own trace, so a request arriving from an already-sampled caller is kept regardless of this number.

response_header: bool

Return the trace id to the caller as X-Trace-Id. What turns “it was slow at 14:02” from a support ticket into a lookup.

capture_headers: Vec<String>

Request headers to copy onto the span. Never include anything that carries a credential — authorization and cookie are refused even if they are listed here.

exclude_paths: Vec<String>

Paths that are never traced, matched as prefixes after base_path. Health checks and asset requests are noise that costs money per span.

Trait Implementations

impl Clone for TracesConfig

fn clone(&self) -> TracesConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TracesConfig

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

Formats the value using the given formatter.

impl Default for TracesConfig

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for TracesConfig

where TracesConfig: Default,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.