Crate reqwest_datadog_tracing 

Opentracing middleware implementation for reqwest_middleware.

Attach TracingMiddleware to your client to automatically trace HTTP requests.

The simplest possible usage:

use reqwest_middleware::{ClientBuilder};
use reqwest_datadog_tracing::TracingMiddleware;

let reqwest_client = reqwest::Client::builder().build().unwrap();
let client = ClientBuilder::new(reqwest_client)
   // Insert the tracing middleware
   .with(TracingMiddleware::default())
   .build();

let resp = client.get("https://truelayer.com").send().await.unwrap();

To customise the span names use OtelName.

use reqwest_middleware::{ClientBuilder, Extension};
use reqwest_datadog_tracing::{
    TracingMiddleware, OtelName
};
let reqwest_client = reqwest::Client::builder().build().unwrap();
let client = ClientBuilder::new(reqwest_client)
   // Inserts the extension before the request is started
   .with_init(Extension(OtelName("my-client".into())))
   // Makes use of that extension to specify the otel name
   .with(TracingMiddleware::default())
   .build();

let resp = client.get("https://truelayer.com").send().await.unwrap();

// Or specify it on the individual request (will take priority)
let resp = client.post("https://api.truelayer.com/payment")
    .with_extension(OtelName("POST /payment".into()))
   .send()
   .await
   .unwrap();

In this example we define a custom span builder to calculate the request time elapsed and we register the TracingMiddleware.

Note that Opentelemetry tracks start and stop already, there is no need to have a custom builder like this.

use reqwest_middleware::Result;
use http::Extensions;
use reqwest::{Request, Response};
use reqwest_middleware::ClientBuilder;
use reqwest_datadog_tracing::{
    default_on_request_end, reqwest_otel_span, ReqwestOtelSpanBackend, TracingMiddleware
};
use tracing::Span;
use std::time::{Duration, Instant};

pub struct TimeTrace;

impl ReqwestOtelSpanBackend for TimeTrace {
    fn on_request_start(req: &Request, extension: &mut Extensions) -> Span {
        extension.insert(Instant::now());
        reqwest_otel_span!(name="example-request", req, time_elapsed = tracing::field::Empty)
    }

    fn on_request_end(span: &Span, outcome: &Result<Response>, extension: &mut Extensions) {
        let time_elapsed = extension.get::<Instant>().unwrap().elapsed().as_millis() as i64;
        default_on_request_end(span, outcome);
        span.record("time_elapsed", &time_elapsed);
    }
}

let http = ClientBuilder::new(reqwest::Client::new())
    .with(TracingMiddleware::<TimeTrace>::new())
    .build();

Macros

reqwest_otel_span

reqwest_otel_span! creates a new tracing::Span. It empowers you to add custom properties to the span on top of the default properties provided by the macro

Structs

DefaultSpanBackend

The default ReqwestOtelSpanBackend for TracingMiddleware. Note that it doesn’t include the url.full field in spans, you can use SpanBackendWithUrl to add it.

DisableOtelPropagation

DisableOtelPropagation disables opentelemetry header propagation, while still tracing the HTTP request.

OtelName

OtelName allows customisation of the name of the spans created by DefaultSpanBackend and SpanBackendWithUrl.

OtelPathNames

OtelPathNames allows including templated paths in the spans created by DefaultSpanBackend and SpanBackendWithUrl.

SpanBackendWithUrl

Similar to DefaultSpanBackend but also adds the url.full attribute to request spans.

TracingMiddleware

Middleware for tracing requests using the current Opentelemetry Context.

Constants

ERROR_CAUSE_CHAIN

The error.cause_chain field added to the span by reqwest_otel_span

ERROR_MESSAGE

The error.message field added to the span by reqwest_otel_span

HTTP_REQUEST_METHOD

The http.request.method field added to the span by reqwest_otel_span

HTTP_RESPONSE_STATUS_CODE

The http.response.status_code field added to the span by reqwest_otel_span

OTEL_KIND

The otel.kind field added to the span by reqwest_otel_span

OTEL_NAME

The otel.name field added to the span by reqwest_otel_span

OTEL_STATUS_CODE

The otel.status_code field added to the span by reqwest_otel_span

SERVER_ADDRESS

The server.address field added to the span by reqwest_otel_span

SERVER_PORT

The server.port field added to the span by reqwest_otel_span

URL_FULL

The url.full field added to the span by reqwest_otel_span

URL_SCHEME

The url.scheme field added to the span by reqwest_otel_span

USER_AGENT_ORIGINAL

The user_agent.original field added to the span by reqwest_otel_span

Traits

ReqwestOtelSpanBackend

ReqwestOtelSpanBackend allows you to customise the span attached by TracingMiddleware to incoming requests.

Functions

default_on_request_end

Populates default success/failure fields for a given reqwest_otel_span! span.

default_on_request_failure

Populates default failure fields for a given reqwest_otel_span! span.

default_on_request_success

Populates default success fields for a given reqwest_otel_span! span.

default_span_name

Determine the name of the span that should be associated with this request.