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use crossbeam_channel::unbounded;
use rand::random;
use super::super::ImplContextBox;
use super::super::Result;
use super::super::FinishedSpan;
use super::super::Span;
use super::super::SpanContext;
use super::super::SpanReceiver;
use super::super::SpanReference;
use super::super::SpanReferenceAware;
use super::super::SpanSender;
use super::super::StartOptions;
use super::super::ExtractFormat;
use super::super::InjectFormat;
use super::super::Tracer;
use super::super::TracerInterface;
pub struct NoopTracer {
sender: SpanSender
}
impl TracerInterface for NoopTracer {
fn extract(&self, _fmt: ExtractFormat) -> Result<Option<SpanContext>> {
Ok(None)
}
fn inject(&self, _context: &SpanContext, _fmt: InjectFormat) -> Result<()> {
Ok(())
}
fn span(&self, name: &str, options: StartOptions) -> Span {
let trace_id = random::<[u8; 16]>();
let span_id = random::<u64>();
let context = SpanContext::new(ImplContextBox::new(NoopTracerContext {
trace_id,
span_id
}));
Span::new(name, context, options, self.sender.clone())
}
}
impl NoopTracer {
pub fn new() -> (Tracer, SpanReceiver) {
let (sender, receiver) = unbounded();
let tracer = NoopTracer { sender };
(Tracer::new(tracer), receiver)
}
pub fn report(span: FinishedSpan) {
drop(span);
}
}
#[derive(Clone, Debug)]
struct NoopTracerContext {
trace_id: [u8; 16],
span_id: u64
}
impl SpanReferenceAware for NoopTracerContext {
fn reference_span(&mut self, reference: &SpanReference) {
match reference {
&SpanReference::ChildOf(ref parent) |
&SpanReference::FollowsFrom(ref parent) => {
let context = parent.impl_context::<NoopTracerContext>();
let context = context.expect(
"Unsupported span context, was it created by NoopTracer?"
);
self.trace_id = context.trace_id;
}
}
}
}
#[cfg(test)]
mod tests {
mod inner_context {
use super::super::super::super::ImplContextBox;
use super::super::super::super::SpanContext;
use super::super::super::super::SpanReference;
use super::super::super::super::SpanReferenceAware;
use super::super::NoopTracer;
use super::super::NoopTracerContext;
#[derive(Clone)]
struct OtherContext {}
impl SpanReferenceAware for OtherContext {
fn reference_span(&mut self, _: &SpanReference) {}
}
#[test]
fn child_of_updates_trace_id() {
let (tracer, _) = NoopTracer::new();
let parent = tracer.span("test1");
let mut span = tracer.span("test2");
span.child_of(parent.context().clone());
let inner_parent = parent.context().impl_context::<NoopTracerContext>().unwrap();
let inner_span = span.context().impl_context::<NoopTracerContext>().unwrap();
assert_eq!(inner_parent.trace_id, inner_span.trace_id);
}
#[test]
fn follows_updates_trace_id() {
let (tracer, _) = NoopTracer::new();
let parent = tracer.span("test1");
let mut span = tracer.span("test2");
span.follows(parent.context().clone());
let inner_parent = parent.context().impl_context::<NoopTracerContext>().unwrap();
let inner_span = span.context().impl_context::<NoopTracerContext>().unwrap();
assert_eq!(inner_parent.trace_id, inner_span.trace_id);
}
#[test]
#[should_panic(expected = "Unsupported span context, was it created by NoopTracer?")]
fn panics_if_invalid_context() {
let (tracer, _) = NoopTracer::new();
let parent = SpanContext::new(ImplContextBox::new(OtherContext{}));
let mut span = tracer.span("test");
span.child_of(parent);
}
}
}