Struct TraceContext

pub struct TraceContext { /* private fields */ }

Extract and apply Trace-Context headers.

Specifications

• Trace-Context (Working Draft)

Examples

use http_types::trace::TraceContext;

let mut res = http_types::Response::new(200);

res.insert_header(
    "traceparent",
    "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01"
);

let context = TraceContext::from_headers(&res)?.unwrap();

let trace_id = u128::from_str_radix("0af7651916cd43dd8448eb211c80319c", 16);
let parent_id = u64::from_str_radix("00f067aa0ba902b7", 16);

assert_eq!(context.trace_id(), trace_id.unwrap());
assert_eq!(context.parent_id(), parent_id.ok());
assert_eq!(context.sampled(), true);

Implementations

impl TraceContext

pub fn new() -> Self

Generate a new TraceContext object without a parent.

By default root TraceContext objects are sampled. To mark it unsampled, call context.set_sampled(false).

Examples

use http_types::trace::TraceContext;

let context = TraceContext::new();

assert_eq!(context.parent_id(), None);
assert_eq!(context.sampled(), true);

pub fn from_headers(headers: impl AsRef<Headers>) -> Result<Option<Self>>

Create and return TraceContext object based on traceparent HTTP header.

Errors

This function may error if the header is malformed. An error with a status code of 400: Bad Request will be generated.

Examples

use http_types::trace::TraceContext;

let mut res = http_types::Response::new(200);
res.insert_header(
  "traceparent",
  "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01"
);

let context = TraceContext::from_headers(&res)?.unwrap();

let trace_id = u128::from_str_radix("0af7651916cd43dd8448eb211c80319c", 16);
let parent_id = u64::from_str_radix("00f067aa0ba902b7", 16);

assert_eq!(context.trace_id(), trace_id.unwrap());
assert_eq!(context.parent_id(), parent_id.ok());
assert_eq!(context.sampled(), true);

pub fn apply(&self, headers: impl AsMut<Headers>)

Add the traceparent header to the http headers

Examples

use http_types::trace::TraceContext;
use http_types::{Request, Response, Url, Method};

let mut req = Request::new(Method::Get, Url::parse("https://example.com").unwrap());
req.insert_header(
  "traceparent",
  "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01"
);

let parent = TraceContext::from_headers(&req)?.unwrap();

let mut res = Response::new(200);
parent.apply(&mut res);

let child = TraceContext::from_headers(&res)?.unwrap();

assert_eq!(child.version(), parent.version());
assert_eq!(child.trace_id(), parent.trace_id());
assert_eq!(child.parent_id(), Some(parent.id()));

pub fn name(&self) -> HeaderName

Get the HeaderName.

pub fn value(&self) -> HeaderValue

Get the HeaderValue.

pub fn child(&self) -> Self

Generate a child of the current TraceContext and return it.

The child will have a new randomly genrated id and its parent_id will be set to the id of this TraceContext.

pub fn id(&self) -> u64

Return the id of the TraceContext.

pub fn version(&self) -> u8

Return the version of the TraceContext spec used.

You probably don’t need this.

pub fn trace_id(&self) -> u128

Return the trace id of the TraceContext.

All children will have the same trace_id.

pub fn parent_id(&self) -> Option<u64>

Return the id of the parent TraceContext.

pub fn sampled(&self) -> bool

Returns true if the trace is sampled

Examples

use http_types::trace::TraceContext;
use http_types::Response;

let mut res = Response::new(200);
res.insert_header("traceparent", "00-00000000000000000000000000000001-0000000000000002-01");
let context = TraceContext::from_headers(&res)?.unwrap();
assert_eq!(context.sampled(), true);

pub fn set_sampled(&mut self, sampled: bool)

Change sampled flag

Examples

use http_types::trace::TraceContext;

let mut context = TraceContext::new();
assert_eq!(context.sampled(), true);
context.set_sampled(false);
assert_eq!(context.sampled(), false);

Trait Implementations

impl Debug for TraceContext

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

Formats the value using the given formatter.

impl Display for TraceContext

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

Formats the value using the given formatter.