elixir-mint / mint / 4a195ffb5536719985d1bc3d22b7eadc21ee1651

88%

push

github

Add Mint.HTTP2.set_window_size/3 (#480)

Advertises a larger HTTP/2 receive window (connection-level or
per-stream) by sending a WINDOW_UPDATE frame. Needed because RFC 7540
makes the connection-level initial window tunable only via
WINDOW_UPDATE — not SETTINGS — leaving the spec default of 64 KB as
the only reachable value without an API like this.

In hex's `mix deps.get` — many parallel multi-MB tarball downloads
sharing one HTTP/2 connection — raising the connection window from
64 KB to 8 MB via this function drops 10 runs from 32.7s to 29.2s
(10.8%), matching their HTTP/1 pool.

Deliberately asymmetric with get_window_size/2 (which returns the
client *send* window). Docstrings on both carry warning callouts
spelling out send-vs-receive so callers don't assume they round-trip.

Target is :connection or {:request, ref}; grow-only (shrink attempts
return {:error, conn, %HTTPError{reason: :window_size_too_small}});
new_size validated against 1..2^31-1. Tracks the advertised peak on
new receive_window_size fields on the connection and stream.

---------

Co-authored-by: Andrea Leopardi <an.leopardi@gmail.com>

29 of 31 new or added lines in 1 file covered. (93.55%)

1318 of 1501 relevant lines covered (87.81%)

252.91 hits per line