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author | JoramWilander <jwawilander@gmail.com> | 2018-07-10 15:01:43 -0400 |
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committer | JoramWilander <jwawilander@gmail.com> | 2018-07-10 15:01:43 -0400 |
commit | 6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005 (patch) | |
tree | 5564a47257bf6e85aaef711980c5b0fcb4d07dcc /vendor/google.golang.org/grpc/grpclb_picker.go | |
parent | c042ffa460296587579aff54b157a5109e022f7e (diff) | |
parent | 1e1a5e5e85240f25c4faddcb24c5a29a915fe6e4 (diff) | |
download | chat-6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005.tar.gz chat-6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005.tar.bz2 chat-6c7dc2d29ccac5f9925402f6be1a4c2a3c46c005.zip |
Merge branch 'plugins-2'
Diffstat (limited to 'vendor/google.golang.org/grpc/grpclb_picker.go')
-rw-r--r-- | vendor/google.golang.org/grpc/grpclb_picker.go | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/grpclb_picker.go b/vendor/google.golang.org/grpc/grpclb_picker.go new file mode 100644 index 000000000..872c7ccea --- /dev/null +++ b/vendor/google.golang.org/grpc/grpclb_picker.go @@ -0,0 +1,159 @@ +/* + * + * Copyright 2017 gRPC authors. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + */ + +package grpc + +import ( + "sync" + "sync/atomic" + + "golang.org/x/net/context" + "google.golang.org/grpc/balancer" + "google.golang.org/grpc/codes" + lbpb "google.golang.org/grpc/grpclb/grpc_lb_v1/messages" + "google.golang.org/grpc/status" +) + +type rpcStats struct { + NumCallsStarted int64 + NumCallsFinished int64 + NumCallsFinishedWithDropForRateLimiting int64 + NumCallsFinishedWithDropForLoadBalancing int64 + NumCallsFinishedWithClientFailedToSend int64 + NumCallsFinishedKnownReceived int64 +} + +// toClientStats converts rpcStats to lbpb.ClientStats, and clears rpcStats. +func (s *rpcStats) toClientStats() *lbpb.ClientStats { + stats := &lbpb.ClientStats{ + NumCallsStarted: atomic.SwapInt64(&s.NumCallsStarted, 0), + NumCallsFinished: atomic.SwapInt64(&s.NumCallsFinished, 0), + NumCallsFinishedWithDropForRateLimiting: atomic.SwapInt64(&s.NumCallsFinishedWithDropForRateLimiting, 0), + NumCallsFinishedWithDropForLoadBalancing: atomic.SwapInt64(&s.NumCallsFinishedWithDropForLoadBalancing, 0), + NumCallsFinishedWithClientFailedToSend: atomic.SwapInt64(&s.NumCallsFinishedWithClientFailedToSend, 0), + NumCallsFinishedKnownReceived: atomic.SwapInt64(&s.NumCallsFinishedKnownReceived, 0), + } + return stats +} + +func (s *rpcStats) dropForRateLimiting() { + atomic.AddInt64(&s.NumCallsStarted, 1) + atomic.AddInt64(&s.NumCallsFinishedWithDropForRateLimiting, 1) + atomic.AddInt64(&s.NumCallsFinished, 1) +} + +func (s *rpcStats) dropForLoadBalancing() { + atomic.AddInt64(&s.NumCallsStarted, 1) + atomic.AddInt64(&s.NumCallsFinishedWithDropForLoadBalancing, 1) + atomic.AddInt64(&s.NumCallsFinished, 1) +} + +func (s *rpcStats) failedToSend() { + atomic.AddInt64(&s.NumCallsStarted, 1) + atomic.AddInt64(&s.NumCallsFinishedWithClientFailedToSend, 1) + atomic.AddInt64(&s.NumCallsFinished, 1) +} + +func (s *rpcStats) knownReceived() { + atomic.AddInt64(&s.NumCallsStarted, 1) + atomic.AddInt64(&s.NumCallsFinishedKnownReceived, 1) + atomic.AddInt64(&s.NumCallsFinished, 1) +} + +type errPicker struct { + // Pick always returns this err. + err error +} + +func (p *errPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { + return nil, nil, p.err +} + +// rrPicker does roundrobin on subConns. It's typically used when there's no +// response from remote balancer, and grpclb falls back to the resolved +// backends. +// +// It guaranteed that len(subConns) > 0. +type rrPicker struct { + mu sync.Mutex + subConns []balancer.SubConn // The subConns that were READY when taking the snapshot. + subConnsNext int +} + +func (p *rrPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { + p.mu.Lock() + defer p.mu.Unlock() + sc := p.subConns[p.subConnsNext] + p.subConnsNext = (p.subConnsNext + 1) % len(p.subConns) + return sc, nil, nil +} + +// lbPicker does two layers of picks: +// +// First layer: roundrobin on all servers in serverList, including drops and backends. +// - If it picks a drop, the RPC will fail as being dropped. +// - If it picks a backend, do a second layer pick to pick the real backend. +// +// Second layer: roundrobin on all READY backends. +// +// It's guaranteed that len(serverList) > 0. +type lbPicker struct { + mu sync.Mutex + serverList []*lbpb.Server + serverListNext int + subConns []balancer.SubConn // The subConns that were READY when taking the snapshot. + subConnsNext int + + stats *rpcStats +} + +func (p *lbPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) { + p.mu.Lock() + defer p.mu.Unlock() + + // Layer one roundrobin on serverList. + s := p.serverList[p.serverListNext] + p.serverListNext = (p.serverListNext + 1) % len(p.serverList) + + // If it's a drop, return an error and fail the RPC. + if s.DropForRateLimiting { + p.stats.dropForRateLimiting() + return nil, nil, status.Errorf(codes.Unavailable, "request dropped by grpclb") + } + if s.DropForLoadBalancing { + p.stats.dropForLoadBalancing() + return nil, nil, status.Errorf(codes.Unavailable, "request dropped by grpclb") + } + + // If not a drop but there's no ready subConns. + if len(p.subConns) <= 0 { + return nil, nil, balancer.ErrNoSubConnAvailable + } + + // Return the next ready subConn in the list, also collect rpc stats. + sc := p.subConns[p.subConnsNext] + p.subConnsNext = (p.subConnsNext + 1) % len(p.subConns) + done := func(info balancer.DoneInfo) { + if !info.BytesSent { + p.stats.failedToSend() + } else if info.BytesReceived { + p.stats.knownReceived() + } + } + return sc, done, nil +} |