Part of C2P fallback. To support fallback to a DNS cluster.
This PR adds implementation of xds_cluster_impl_balancer, which will be responsible for circuit breaking and rpc dropping.
This PR only added RPC dropping. Circuit breaking will be done in a followup PR, after some necessary refactoring.
Replace various //go:generate lines and regenerate.sh scripts with a
single, top-level regenerate.sh that regenerates all .pb.go files.
Placing generation in a single script ensures that all files are
generated with similar parameters. The new regenerate.sh uses the
protoc-gen-go version defined in test/tools/go.mod and automatically
handles new .proto files as they are added.
Do some minor refactoring on .proto files: Every file now has a
go_package option (which will be required by a future version of the
code generator), and file imports are all relative to the repository
root.
golint does check for missing package comment, but with low confidence.
golint checks each file, and complains on every file missing package comment, even though another file in the same package has the comment.
This PR adds a golint check with low min_confidence, and filters out false-positives.
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%
* Add a helper to the fakexds package to return a ClientConn talking to
the fake server.
* Tests will make use of this ClientConn wherever required, or they will
directly pass the fake server's address as the balancerName to the
xdsclient.New() function, thus exercising that code path as well.
* Add grpc.WithTimeout to list in vet.sh
This is necessary because there's another way to select grpclb (by specifying grpclb in service config's balancing policy field). So it's possible that grpclb is picked, but resolver doesn't have any balancer addresses.
When an update without balancer address is received, grpclb closes the underlying ClientConn to remote balancer, and enters fallback mode.
Note that grpclb waits until the ClientConn and the RPC goroutines are actually closed to do the fallback work. This can avoid race caused by async close.
Nobody should directly need to reference these packages.
This is technically a breaking change. However:
- Package dns was exporting a NewBuilder method. This should never have been necessary to use, but if so, it can be replaced by importing the "grpc" package and then using resolver.Get("dns").
- Package passthrough was not exporting any symbols and there was never a need to even blank-import it.
After as much searching as possible, it appears nobody in the open source community is referencing either of these packages.
Also, two fixes:
- Fix long-standing `.travis.yml` bug where `VET_SKIP_PROTO` was not `export`ed (so not seen by `vet.sh`).
- Update `vet.sh` to work with new `goimports -l` that does not print a `:` after filenames.
This resolver doesn't do much at this point, except returning an empty
address list and a hard-coded service config which picks the xds
balancer with a round_robin child policy.
Also moved the xdsConfig struct to the xds/internal package and exported
it as LBConfig, so that both the resolver and the balancer packages can
make use of this.
We will have a root level xds/ directory which will eventually contain
all xDS implementation including balancer, resolver, client etc.
The new structure looks something like this:
grpc/
|
+--xds/
|
+--internal/
| |
| +--balancer/
| |
| +--edsbalancer/
| |
| +--lrs/
| |
| +--orca/
|
+--experimental/
Users need to import grpc/xds/experimental package to get all xds
functionality, and this will eventually be moved to grpc/xds.
Also, moved grpc/balancer/internal/wrr to grpc/internal/wrr.
Arvind Bright
Doug Fawley
Easwar Swaminathan
Eric Butler
ZhenLian
Menghan Li
Timothy Gu
Garrett Gutierrez
Damien Neil
Egon Elbre
Garrett Gutierrez
Adhityaa Chandrasekar