tower_http/trace/
on_body_chunk.rs

1use std::time::Duration;
2use tracing::Span;
3
4/// Trait used to tell [`Trace`] what to do when a body chunk has been sent.
5///
6/// See the [module docs](../trace/index.html#on_body_chunk) for details on exactly when the
7/// `on_body_chunk` callback is called.
8///
9/// [`Trace`]: super::Trace
10pub trait OnBodyChunk<B> {
11    /// Do the thing.
12    ///
13    /// `latency` is the duration since the response was sent or since the last body chunk as sent.
14    ///
15    /// `span` is the `tracing` [`Span`], corresponding to this request, produced by the closure
16    /// passed to [`TraceLayer::make_span_with`]. It can be used to [record field values][record]
17    /// that weren't known when the span was created.
18    ///
19    /// [`Span`]: https://docs.rs/tracing/latest/tracing/span/index.html
20    /// [record]: https://docs.rs/tracing/latest/tracing/span/struct.Span.html#method.record
21    ///
22    /// If you're using [hyper] as your server `B` will most likely be [`Bytes`].
23    ///
24    /// [hyper]: https://hyper.rs
25    /// [`Bytes`]: https://docs.rs/bytes/latest/bytes/struct.Bytes.html
26    /// [`TraceLayer::make_span_with`]: crate::trace::TraceLayer::make_span_with
27    fn on_body_chunk(&mut self, chunk: &B, latency: Duration, span: &Span);
28}
29
30impl<B, F> OnBodyChunk<B> for F
31where
32    F: FnMut(&B, Duration, &Span),
33{
34    fn on_body_chunk(&mut self, chunk: &B, latency: Duration, span: &Span) {
35        self(chunk, latency, span)
36    }
37}
38
39impl<B> OnBodyChunk<B> for () {
40    #[inline]
41    fn on_body_chunk(&mut self, _: &B, _: Duration, _: &Span) {}
42}
43
44/// The default [`OnBodyChunk`] implementation used by [`Trace`].
45///
46/// Simply does nothing.
47///
48/// [`Trace`]: super::Trace
49#[derive(Debug, Default, Clone)]
50pub struct DefaultOnBodyChunk {
51    _priv: (),
52}
53
54impl DefaultOnBodyChunk {
55    /// Create a new `DefaultOnBodyChunk`.
56    pub fn new() -> Self {
57        Self { _priv: () }
58    }
59}
60
61impl<B> OnBodyChunk<B> for DefaultOnBodyChunk {
62    #[inline]
63    fn on_body_chunk(&mut self, _: &B, _: Duration, _: &Span) {}
64}
tower_http/trace/on_body_chunk.rs

tower_http/trace/
on_body_chunk.rs
