Import of https://github.com/ciena/voltctl at commit 40d61fbf3f910ed4017cf67c9c79e8e1f82a33a5
Change-Id: I8464c59e60d76cb8612891db3303878975b5416c
diff --git a/vendor/google.golang.org/grpc/pickfirst.go b/vendor/google.golang.org/grpc/pickfirst.go
new file mode 100644
index 0000000..d1e38aa
--- /dev/null
+++ b/vendor/google.golang.org/grpc/pickfirst.go
@@ -0,0 +1,110 @@
+/*
+ *
+ * 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 (
+ "context"
+
+ "google.golang.org/grpc/balancer"
+ "google.golang.org/grpc/connectivity"
+ "google.golang.org/grpc/grpclog"
+ "google.golang.org/grpc/resolver"
+)
+
+// PickFirstBalancerName is the name of the pick_first balancer.
+const PickFirstBalancerName = "pick_first"
+
+func newPickfirstBuilder() balancer.Builder {
+ return &pickfirstBuilder{}
+}
+
+type pickfirstBuilder struct{}
+
+func (*pickfirstBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
+ return &pickfirstBalancer{cc: cc}
+}
+
+func (*pickfirstBuilder) Name() string {
+ return PickFirstBalancerName
+}
+
+type pickfirstBalancer struct {
+ cc balancer.ClientConn
+ sc balancer.SubConn
+}
+
+func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
+ if err != nil {
+ grpclog.Infof("pickfirstBalancer: HandleResolvedAddrs called with error %v", err)
+ return
+ }
+ if b.sc == nil {
+ b.sc, err = b.cc.NewSubConn(addrs, balancer.NewSubConnOptions{})
+ if err != nil {
+ //TODO(yuxuanli): why not change the cc state to Idle?
+ grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+ return
+ }
+ b.cc.UpdateBalancerState(connectivity.Idle, &picker{sc: b.sc})
+ b.sc.Connect()
+ } else {
+ b.sc.UpdateAddresses(addrs)
+ b.sc.Connect()
+ }
+}
+
+func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+ grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+ if b.sc != sc {
+ grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+ return
+ }
+ if s == connectivity.Shutdown {
+ b.sc = nil
+ return
+ }
+
+ switch s {
+ case connectivity.Ready, connectivity.Idle:
+ b.cc.UpdateBalancerState(s, &picker{sc: sc})
+ case connectivity.Connecting:
+ b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrNoSubConnAvailable})
+ case connectivity.TransientFailure:
+ b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrTransientFailure})
+ }
+}
+
+func (b *pickfirstBalancer) Close() {
+}
+
+type picker struct {
+ err error
+ sc balancer.SubConn
+}
+
+func (p *picker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+ if p.err != nil {
+ return nil, nil, p.err
+ }
+ return p.sc, nil, nil
+}
+
+func init() {
+ balancer.Register(newPickfirstBuilder())
+}