Skip to content

enhancement(sources): pre-size HTTP request body buffer from Content-Length #25747

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
armleth wants to merge 3 commits into
base: master
Choose a base branch
from
+14 −8
Open

enhancement(sources): pre-size HTTP request body buffer from Content-Length #25747

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
bbf2140
enhancement(sources): pre-size HTTP request body buffer from Content-…
armleth Jul 3, 2026
2c6c5af
chore: drop changelog fragment (using no-changelog label)
armleth Jul 3, 2026
428db8b
chore: drop verbose comment
armleth Jul 3, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 14 additions & 8 deletions src/sources/util/http/encoding.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -60,13 +60,12 @@ pub(crate) fn limited_body(max_body_size: usize) -> BoxedFilter<(Bytes,)> {
max_body_size,
)))
} else {
Ok(())
Ok(declared)
}
})
.untuple_one()
.and(warp::body::stream())
.and_then(move |body| async move {
collect_body_with_limit(body, max_body_size)
.and_then(move |declared: Option<u64>, body| async move {
collect_body_with_limit(body, max_body_size, declared)
.await
.map_err(warp::reject::custom)
})
Expand Down Expand Up @@ -183,14 +182,21 @@ fn decompress_snappy(
feature = "sources-opentelemetry",
test
))]
async fn collect_body_with_limit<S, B>(body: S, max_body_size: usize) -> Result<Bytes, ErrorMessage>
async fn collect_body_with_limit<S, B>(
body: S,
max_body_size: usize,
declared_len: Option<u64>,
) -> Result<Bytes, ErrorMessage>
where
S: futures_util::Stream<Item = Result<B, warp::Error>>,
B: Buf,
{
futures_util::pin_mut!(body);

let mut bytes = BytesMut::new();
let capacity = declared_len
.and_then(|len| usize::try_from(len).ok())
.map_or(0, |len| len.min(max_body_size));
let mut bytes = BytesMut::with_capacity(capacity);
Comment on lines +196 to +199

@chatgpt-codex-connector chatgpt-codex-connector Bot Jul 3, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

P2 Badge Avoid allocating the full declared body before reads

When an unauthenticated HTTP client sends a Content-Length near the configured limit (100 MiB by default via max_decompressed_size_bytes()) and then stalls or disconnects, this allocates that entire buffer before any body bytes are received. I checked the HTTP source call sites in src/sources/util/http/prelude.rs and src/sources/opentelemetry/http.rs; both use this helper for incoming requests, so many concurrent header-only/slow requests can now reserve large amounts of memory where the previous streaming collector only grew after chunks arrived. Consider capping the initial preallocation to a smaller threshold or growing after the first chunk instead of trusting the header up to the full body limit.

Useful? React with 👍 / 👎.

@armleth armleth Jul 3, 2026

Copy link
Copy Markdown
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good point. IMO, it's acceptable given the performance regression that the alternative causes.
What do you guys think about this?

@bruceg bruceg Jul 3, 2026

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'd agree with its suggestion to cap the initial capacity at some suitably large but smaller-than-100MiB number. That would minimize still reallocations, just not eliminate them.

while let Some(chunk) = body.next().await {
let chunk = chunk.map_err(|error| {
ErrorMessage::new(
Expand Down Expand Up @@ -368,7 +374,7 @@ mod tests {
Ok::<_, warp::Error>(Bytes::from_static(b" world")),
]);

let collected = collect_body_with_limit(body, 11).await.unwrap();
let collected = collect_body_with_limit(body, 11, Some(11)).await.unwrap();
assert_eq!(collected, Bytes::from_static(b"hello world"));
}

Expand All @@ -379,7 +385,7 @@ mod tests {
Ok::<_, warp::Error>(Bytes::from_static(b" world")),
]);

let err = collect_body_with_limit(body, 5)
let err = collect_body_with_limit(body, 5, None)
.await
.expect_err("should reject");
assert_eq!(err.status_code(), StatusCode::PAYLOAD_TOO_LARGE);
Expand Down
Loading