如何使用锈菌tracing_distributed

Question

我正在尝试使用锈菌tracing_distributed包，但是在使用它时，我会遇到奇怪和无用的错误，我假设我使用它是错误的，但是没有文档，也没有关于如何使用它的例子。下面是我试图做的事情的一个例子：

let trace = tracing_distributed::register_dist_tracing_root(traceId, remote_parent_span_id));
println!("trace value: {:?}", trace);

// the result of trace is: Err(NoEnabledSpan)

我尝试以traceID和remote_parent_span_id的形式传递一些内容，包括：

traceId = remote_parent_span_id = Some(tracing::Span::current())

以及：

traceId = Some(tracing::Span::current())
remote_parent_span_id = ~someParentRequestIdGeneratedUpstream~

我知道，当前的跨度不会因为尝试而被禁用：

let span = tracing::Span::current();
if span.is_disabled() {
    println!("CURRENT SPAN DISABELED");
}

因此，这使我认为问题来自没有正确设置订阅者。我正在尝试将订阅服务器设置为init函数，该函数在此函数之前调用，如下所示：

let subscriber = tracing_subscriber::registry() // provide underlying span data store
        .with(
            tracing_subscriber::fmt::layer()
                .json()
                .with_span_events(FmtSpan::ACTIVE)
                .event_format(stackdriver::StackDriverEventFormat::default())
                .with_filter(tracing_subscriber::filter::dynamic_filter_fn(
                    move |m, c| filter_layer.enabled(m, c.to_owned()),
                )),
        );

    let _ = tracing::subscriber::set_global_default(subscriber)
        .map_err(|_err| eprintln!("Unable to set global default subscriber"));

有人愿意给我举一个如何使用这个图书馆的例子吗？或者有人能看到我做错了什么吗？我已经试过了我能想到的一切。

Answer 1

tracing-distributed有一个测试，它演示如何创建和使用TelemetryLayer。

我做了一个基于它的演示。在这个演示中，NoEnabledSpan可能是由于缺少#[instrument]而引起的，它为函数foo创建了一个Span。希望这能帮你找到真正的原因。

另外，tracing-honeycomb是tracing-distributed的一个很好的用例，最好检查一下。

use std::sync::{Arc, Mutex};

use tracing::{Id, info};
use tracing::instrument;
use tracing_distributed::{Event, Span, Telemetry, TelemetryLayer};
use tracing_subscriber::layer::SubscriberExt;
use tracing_subscriber::registry;

#[derive(Default, Debug)]
pub struct BlackholeVisitor;

#[derive(PartialEq, Eq, Hash, Copy, Clone, Debug)]
pub struct TraceId(pub(crate) u128);

type SpanId = tracing::Id;

impl tracing::field::Visit for BlackholeVisitor {
    fn record_debug(&mut self, _: &tracing::field::Field, _: &dyn std::fmt::Debug) {}
}

/// Mock telemetry capability
pub struct TestTelemetry {
    spans: Arc<Mutex<Vec<Span<BlackholeVisitor, SpanId, TraceId>>>>,
    events: Arc<Mutex<Vec<Event<BlackholeVisitor, SpanId, TraceId>>>>,
}

impl TestTelemetry {
    pub fn new(
        spans: Arc<Mutex<Vec<Span<BlackholeVisitor, SpanId, TraceId>>>>,
        events: Arc<Mutex<Vec<Event<BlackholeVisitor, SpanId, TraceId>>>>,
    ) -> Self {
        TestTelemetry { spans, events }
    }
}

impl Telemetry for TestTelemetry {
    type Visitor = BlackholeVisitor;
    type TraceId = TraceId;
    type SpanId = SpanId;

    fn mk_visitor(&self) -> Self::Visitor {
        BlackholeVisitor
    }

    fn report_span(&self, span: Span<BlackholeVisitor, SpanId, TraceId>) {
        // succeed or die. failure is unrecoverable (mutex poisoned)
        let mut spans = self.spans.lock().unwrap();
        spans.push(span);
    }

    fn report_event(&self, event: Event<BlackholeVisitor, SpanId, TraceId>) {
        // succeed or die. failure is unrecoverable (mutex poisoned)
        let mut events = self.events.lock().unwrap();
        events.push(event);
    }
}

#[instrument]
fn foo() {
    let trace = tracing_distributed::register_dist_tracing_root(TraceId(123), Option::<Id>::None);
    println!("trace value: {:?}", trace);
    info!("test");
}

fn main() {
    let spans = Arc::new(Mutex::new(Vec::new()));
    let events = Arc::new(Mutex::new(Vec::new()));

    let cap = TestTelemetry::new(spans.clone(), events.clone());

    let telemetry_layer = TelemetryLayer::new("test_svc_name", cap, |x| x);
    let subscriber = registry::Registry::default()
        .with(tracing_subscriber::fmt::Layer::default())
        .with(telemetry_layer);
    // dbg!(&subscriber);
    tracing::subscriber::set_global_default(subscriber).expect("setting global default failed");
    foo();
    dbg!(&spans);
    dbg!(&events);
}

机箱版本：

tracing = "0.1.32"
tracing-distributed = "0.4.0"
tracing-subscriber = "0.3.10"