For transparent retry.
Also allow non-WFR RPCs to retry indefinitely on errors that resulted in no I/O; the spec used to forbid it at one point during development, but it no longer does.
Most interfaces for adding metadata to a context downcase keys, except metadata.AppendToOutgoingContext (presumably for performance reasons). Documentation for metadata.AppendToOutgoingContext, referring to that of metadata.Pairs, states that metadata keys are downcased.
The bug is manifest if you use metadata.AppendToOutgoingContext to add metadata with a non-downcased `-Bin` suffix. http2Client will not encode such metadata, as encodeMetadataHeader just performs a lower suffix check.
Local credentials should be used in either a UDS and local TCP connection. The former will be associated with the security level PrigvacyAndIntegrity while the latter is associated with NoSecurity. Local credentials should be used instead of WithInsecure for localhost connections.
Performance benchmarks can be found below. Obviously, a 8 KiB
request/response is tailored to showcase this improvement as this is
where codec buffer reuse shines, but I've run other benchmarks too (like
1-byte requests and responses) and there's no discernable impact on
performance.
We do not allow reuse of buffers when stat handlers or binlogs are
turned on. This is because those two may need access to the data and
payload even after the data has been written to the wire. In such cases,
we never return the data back to the pool.
A buffer reuse threshold of 1 KiB was determined after several
experiments. There's diminished returns when buffer reuse is enabled for
smaller messages (actually, a negative impact).
unary-networkMode_none-bufConn_false-keepalive_false-benchTime_40s-trace_false-latency_0s-kbps_0-MTU_0-maxConcurrentCalls_6-reqSize_8192B-respSize_8192B-compressor_off-channelz_false-preloader_false
Title Before After Percentage
TotalOps 839638 906223 7.93%
SendOps 0 0 NaN%
RecvOps 0 0 NaN%
Bytes/op 103788.29 80592.47 -22.35%
Allocs/op 183.33 189.30 3.27%
ReqT/op 1375662899.20 1484755763.20 7.93%
RespT/op 1375662899.20 1484755763.20 7.93%
50th-Lat 238.746µs 225.019µs -5.75%
90th-Lat 514.253µs 456.439µs -11.24%
99th-Lat 711.083µs 702.466µs -1.21%
Avg-Lat 285.45µs 264.456µs -7.35%
This commit makes the following changes:
- Keep track of the time of the last read in the transport.
- Use this in the keepalive implementation to decide when to send out
keepalives.
- Address the issue of keepalives being sent every [Time+Timeout] period
instead of every [Time] period, as mandated by proposal A8.
Proposal A8 is here:
https://github.com/grpc/proposal/blob/master/A8-client-side-keepalive.md
Add a RequestInfo struct which initially is used for passing the full request method (though could later be expanded to pass more info) so that things like GetRequestMetadata can be used to apply logic based on that data.
This is a fix for #3019
`transport/Stream.RecvCompress` returns what the header contains, if present,
or empty string if a context error occurs. However, it "prefers" the header
data even if there is a context error, to prevent a related race. What happens
here is:
1. RPC starts.
2. Client cancels RPC.
3. `RecvCompress` tells `ClientStream.Recv` that compression used is "" because
of the context error. `as.decomp` is left nil, because there is no
compressor to look up in the registry.
4. Server's header and first message hit client.
5. Client sees the header and message and allows grpc's stream to see them.
(We only provide context errors if we need to block.)
6. Client performs a successful `Read` on the stream, receiving the gzipped
payload, then checks `as.decomp`.
7. We have no decompressor but the payload has a bit set indicating the message
is compressed, so this is an error. However, when forming the error string,
`RecvCompress` now returns "gzip" because it doesn't need to block to get
this from the now-received header. This leads to the confusing message
about how "gzip" is not installed even though it is.
This change makes `waitOnHeader` close the stream when context cancellation happens.
Then `RecvCompress` uses whatever value is present in the stream at that time, which
can no longer change because the stream is closed. Also, this will be in sync with
the messages on the stream - if there are any messages present, the headers must
have been processed first, and `RecvCompress` will contain the proper value.
The current code was using a buffered channel which was used to signal
whether the keepalive goroutine should enter dormancy or if it should be
awaked from sleep. Using sync.Cond makes the code much simpler to read,
and also improves the performance numbers in all but one front.
Easwar Swaminathan
Doug Fawley
Menghan Li
John Howard
James Protzman
Vicent Martí
Zach Reyes
apolcyn
Edmond
Garrett Gutierrez
yihuaz
Nick Jones
Garrett Gutierrez
Sorah Fukumori
Tzu-Chiao Yeh
Bryan Boreham
Matthew Dolan
Adhityaa Chandrasekar
Piotr Kowalczuk
Adhityaa Chandrasekar
Jiacai Liu
Shane Liebling