This commit fixes a request handling bug introduced in #6868, which
caused OPA to treat all incoming chunked requests as if they had
zero-length request bodies.
The fix detects cases where the request body size is unknown in the
DecodingLimits handler, and propagates a request context key down to
the `util.ReadMaybeCompressedBody` function, allowing it to correctly
select between using the original `io.ReadAll` style for chunked
requests, or the newer preallocated buffers approach (for requests of
known size).
This change has a small, but barely visible performance impact for large
requests (<5% increase in GC pauses for a 1GB request JSON blob), and
minimal, if any, effect on RPS under load.
Fixes: #6904
Signed-off-by: Philip Conrad <philip@chariot-chaser.net>
This commit introduces a few major changes:
- (Breaking change) Limits now exist for maximum request body sizes.
- Buffers are preallocated for reading request bodies.
- Buffers are preallocated for decompressing request bodies.
- Gzip decoder instances are reused in a `sync.Pool` across requests.
The effect on garbage collection is dramatically fewer GC pauses, giving
a roughly 9% RPS improvement in load tests with gzipped request bodies.
For larger request sizes, the number of GC pauses is dramatically
reduced, although the peak pause time may increase by a few percent.
Implementation notes:
- The DecodingLimits handler enforces the max request body size both
through a Content-Length check, and a MaxBytesReader wrapper around
the payload.
- The DecodingLimits handler passes the gzip payload size limit down
using a context key.
Signed-off-by: Philip Conrad <philipaconrad@gmail.com>
Philip Conrad