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feat(client): report checkout, write, header-wait and body-read phase timings #15

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Merged
casibbald merged 1 commit into from
Nov 3, 2026
Merged

feat(client): report checkout, write, header-wait and body-read phase timings #15

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33 changes: 33 additions & 0 deletions src/client/observer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,39 @@ pub enum ClientEvent<'a> {
request_id: u64,
origin: ObservedOrigin<'a>,
},
/// The pool handed out a connection: reused, newly connected (DNS and connect included), or
/// after waiting for one. One per attempt.
CheckoutCompleted {
request_id: u64,
origin: ObservedOrigin<'a>,
duration: Duration,
reused: bool,
error: Option<ClientErrorKind>,
},
/// The request head and body were written to the connection.
RequestWritten {
request_id: u64,
origin: ObservedOrigin<'a>,
duration: Duration,
error: Option<ClientErrorKind>,
},
/// From the request being written to the response head being read: the server's time plus
/// the network, as the client sees it.
ResponseHeadersReceived {
request_id: u64,
origin: ObservedOrigin<'a>,
duration: Duration,
error: Option<ClientErrorKind>,
},
/// The response body was read in full by the buffered client (`send`). Streaming responses
/// are read by the caller, which times them itself.
ResponseBodyRead {
request_id: u64,
origin: ObservedOrigin<'a>,
duration: Duration,
bytes: usize,
error: Option<ClientErrorKind>,
},
ResponseHeaders {
request_id: u64,
origin: ObservedOrigin<'a>,
Expand Down
205 changes: 179 additions & 26 deletions src/client/rich.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -889,6 +889,7 @@ impl<I: Interceptor> Client<I> {
body,
deadline,
&trace.span,
trace.request_id,
)?;

let status = response.status();
Expand Down Expand Up @@ -938,31 +939,44 @@ impl<I: Interceptor> Client<I> {
"http_client_body",
"http.response.body.size" = tracing::field::Empty
);
loop {
if response.body_complete() {
break;
}
let remaining = remaining(deadline)?;
response.set_timeout(Some(self.inner.config.io_timeout.min(remaining)))?;
if bytes.len() == bytes.capacity() {
bytes.reserve(8 * 1024);
}
let filled = bytes.len();
let allowed = (bytes.capacity() - filled).min(limit - filled.min(limit) + 1);
bytes.resize(filled + allowed, 0);
let read = response.read(&mut bytes[filled..])?;
bytes.truncate(filled + read);
if read == 0 {
break;
let body_started = Instant::now();
let body_read = (|| -> io::Result<()> {
loop {
if response.body_complete() {
break;
}
let remaining = remaining(deadline)?;
response.set_timeout(Some(self.inner.config.io_timeout.min(remaining)))?;
if bytes.len() == bytes.capacity() {
bytes.reserve(8 * 1024);
}
let filled = bytes.len();
let allowed =
(bytes.capacity() - filled).min(limit - filled.min(limit) + 1);
bytes.resize(filled + allowed, 0);
let read = response.read(&mut bytes[filled..])?;
bytes.truncate(filled + read);
if read == 0 {
break;
}
if bytes.len() > limit {
response.abandon_body();
return Err(io::Error::new(
io::ErrorKind::InvalidData,
format!("HTTP response body exceeds configured {limit}-byte limit"),
));
}
}
if bytes.len() > limit {
response.abandon_body();
return Err(io::Error::new(
io::ErrorKind::InvalidData,
format!("HTTP response body exceeds configured {limit}-byte limit"),
));
}
}
Ok(())
})();
self.inner.observe(ClientEvent::ResponseBodyRead {
request_id: trace.request_id,
origin: observed_url(url),
duration: body_started.elapsed(),
bytes: bytes.len(),
error: body_read.as_ref().err().map(ClientErrorKind::classify),
});
body_read?;
span_record!(body_span, "http.response.body.size", bytes.len() as u64);
drop(body_span);
drop(response);
Expand Down Expand Up @@ -1090,6 +1104,7 @@ impl<I: Interceptor> Client<I> {
body,
deadline,
&trace.span,
trace.request_id,
);
if I::ENABLED {
if let Some(timing) = &timing {
Expand Down Expand Up @@ -1398,8 +1413,10 @@ impl<I: Interceptor> Client<I> {
body: &mut RequestBody,
deadline: Instant,
span: &trace::Span,
request_id: u64,
) -> io::Result<super::Response> {
let _ = span;
let write_started = Instant::now();
if headers.contains_key(HOST) {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
Expand Down Expand Up @@ -1454,15 +1471,30 @@ impl<I: Interceptor> Client<I> {
}
}
let client = &mut lease.connection_mut().client;
client.write_request(request)?;
let written = client.write_request(request);
drop(write_span);
self.inner.observe(ClientEvent::RequestWritten {
request_id,
origin: observed_url(url),
duration: write_started.elapsed(),
error: written.as_ref().err().map(ClientErrorKind::classify),
});
written?;
let wait_started = Instant::now();
let wait_span = phase_span!(
DEBUG,
parent: span,
"http_client_wait",
"http.response.status_code" = tracing::field::Empty
);
let response = client.read_response()?;
let response = client.read_response();
self.inner.observe(ClientEvent::ResponseHeadersReceived {
request_id,
origin: observed_url(url),
duration: wait_started.elapsed(),
error: response.as_ref().err().map(ClientErrorKind::classify),
});
let response = response?;
span_record!(
wait_span,
"http.response.status_code",
Expand Down Expand Up @@ -1530,12 +1562,34 @@ impl<I: Interceptor> Client<I> {
}
}

/// Take a connection for `key` (reused, new, or after waiting), reporting how long that took.
fn checkout(
&self,
key: &OriginKey,
tls_config: Arc<ClientConfig>,
deadline: Instant,
trace: &RequestTrace,
) -> io::Result<PoolLease> {
let started = Instant::now();
let lease = self.checkout_connection(key, tls_config, deadline, trace);
self.inner.observe(ClientEvent::CheckoutCompleted {
request_id: trace.request_id,
origin: observed_key(key),
duration: started.elapsed(),
reused: lease
.as_ref()
.is_ok_and(|lease| lease.reused_idle_connection),
error: lease.as_ref().err().map(ClientErrorKind::classify),
});
lease
}

fn checkout_connection(
&self,
key: &OriginKey,
tls_config: Arc<ClientConfig>,
deadline: Instant,
trace: &RequestTrace,
) -> io::Result<PoolLease> {
loop {
let now = Instant::now();
Expand Down Expand Up @@ -2780,6 +2834,11 @@ mod tests {
ClientEvent::RequestAbandoned {
request_id, status, ..
} => format!("abandoned:{request_id}:{}", status.as_u16()),
// Phase timings: asserted by `observer_reports_request_phase_timings`.
ClientEvent::CheckoutCompleted { .. }
| ClientEvent::RequestWritten { .. }
| ClientEvent::ResponseHeadersReceived { .. }
| ClientEvent::ResponseBodyRead { .. } => return,
};
self.0.lock().unwrap().push(value);
}
Expand Down Expand Up @@ -3689,6 +3748,100 @@ mod tests {
assert!(!joined.contains("secret"));
}

#[derive(Default)]
struct PhaseObserver(StdMutex<Vec<(String, Duration)>>);

impl ClientObserver for PhaseObserver {
fn observe(&self, event: ClientEvent<'_>) {
let entry = match event {
ClientEvent::CheckoutCompleted {
request_id,
duration,
reused,
error,
..
} => (
format!("checkout:{request_id}:{reused}:{error:?}"),
duration,
),
ClientEvent::RequestWritten {
request_id,
duration,
error,
..
} => (format!("written:{request_id}:{error:?}"), duration),
ClientEvent::ResponseHeadersReceived {
request_id,
duration,
error,
..
} => (format!("headers:{request_id}:{error:?}"), duration),
ClientEvent::ResponseBodyRead {
request_id,
duration,
bytes,
error,
..
} => (format!("body:{request_id}:{bytes}:{error:?}"), duration),
_ => return,
};
self.0.lock().unwrap().push(entry);
}
}

#[test]
fn observer_reports_request_phase_timings() {
let listener = TcpListener::bind("127.0.0.1:0").unwrap();
let port = listener.local_addr().unwrap().port();
let server = thread::spawn(move || {
let (mut stream, _) = listener.accept().unwrap();
for _ in 0..2 {
let _ = read_head(&mut stream);
// the server "thinks" before answering: that is header wait, not write or body
thread::sleep(Duration::from_millis(60));
stream
.write_all(b"HTTP/1.1 200 OK\r\nContent-Length: 2\r\n\r\nok")
.unwrap();
stream.flush().unwrap();
}
});
let observer = Arc::new(PhaseObserver::default());
let client = Client::builder()
.observer(observer.clone())
.build()
.unwrap();
for _ in 0..2 {
let response = client
.get(&format!("http://127.0.0.1:{port}/phases"))
.unwrap()
.send()
.unwrap();
assert_eq!(response.body(), b"ok");
}
server.join().unwrap();

let events = observer.0.lock().unwrap().clone();
let names: Vec<&str> = events.iter().map(|(name, _)| name.as_str()).collect();
assert_eq!(
names,
[
"checkout:1:false:None",
"written:1:None",
"headers:1:None",
"body:1:2:None",
"checkout:2:true:None",
"written:2:None",
"headers:2:None",
"body:2:2:None",
]
);
let duration = |name: &str| events.iter().find(|(n, _)| n == name).unwrap().1;
assert!(duration("headers:1:None") >= Duration::from_millis(60));
assert!(duration("headers:2:None") >= Duration::from_millis(60));
assert!(duration("written:2:None") < Duration::from_millis(60));
assert!(duration("body:2:2:None") < Duration::from_millis(60));
}

#[test]
fn fully_consumed_streaming_response_reuses_the_connection() {
let listener = TcpListener::bind("127.0.0.1:0").unwrap();
Expand Down
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