VOL-1967 move api-server to separate repository
Change-Id: I21b85be74205805be15f8a85e53a903d16785671
diff --git a/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go
new file mode 100644
index 0000000..4c4ad36
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/balancer/connectivity/connectivity.go
@@ -0,0 +1,93 @@
+// Copyright 2019 The etcd 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 connectivity implements client connectivity operations.
+package connectivity
+
+import (
+ "sync"
+
+ "go.uber.org/zap"
+ "google.golang.org/grpc/connectivity"
+)
+
+// Recorder records gRPC connectivity.
+type Recorder interface {
+ GetCurrentState() connectivity.State
+ RecordTransition(oldState, newState connectivity.State)
+}
+
+// New returns a new Recorder.
+func New(lg *zap.Logger) Recorder {
+ return &recorder{lg: lg}
+}
+
+// recorder takes the connectivity states of multiple SubConns
+// and returns one aggregated connectivity state.
+// ref. https://github.com/grpc/grpc-go/blob/master/balancer/balancer.go
+type recorder struct {
+ lg *zap.Logger
+
+ mu sync.RWMutex
+
+ cur connectivity.State
+
+ numReady uint64 // Number of addrConns in ready state.
+ numConnecting uint64 // Number of addrConns in connecting state.
+ numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+func (rc *recorder) GetCurrentState() (state connectivity.State) {
+ rc.mu.RLock()
+ defer rc.mu.RUnlock()
+ return rc.cur
+}
+
+// RecordTransition records state change happening in subConn and based on that
+// it evaluates what aggregated state should be.
+//
+// - If at least one SubConn in Ready, the aggregated state is Ready;
+// - Else if at least one SubConn in Connecting, the aggregated state is Connecting;
+// - Else the aggregated state is TransientFailure.
+//
+// Idle and Shutdown are not considered.
+//
+// ref. https://github.com/grpc/grpc-go/blob/master/balancer/balancer.go
+func (rc *recorder) RecordTransition(oldState, newState connectivity.State) {
+ rc.mu.Lock()
+ defer rc.mu.Unlock()
+
+ for idx, state := range []connectivity.State{oldState, newState} {
+ updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+ switch state {
+ case connectivity.Ready:
+ rc.numReady += updateVal
+ case connectivity.Connecting:
+ rc.numConnecting += updateVal
+ case connectivity.TransientFailure:
+ rc.numTransientFailure += updateVal
+ default:
+ rc.lg.Warn("connectivity recorder received unknown state", zap.String("connectivity-state", state.String()))
+ }
+ }
+
+ switch { // must be exclusive, no overlap
+ case rc.numReady > 0:
+ rc.cur = connectivity.Ready
+ case rc.numConnecting > 0:
+ rc.cur = connectivity.Connecting
+ default:
+ rc.cur = connectivity.TransientFailure
+ }
+}