[VOL-3255] enhancement to support device metrics
Change-Id: Ic26c2db30a58943a4eef6276ae1cf40350d51702
diff --git a/vendor/google.golang.org/grpc/pickfirst.go b/vendor/google.golang.org/grpc/pickfirst.go
new file mode 100644
index 0000000..c43dac9
--- /dev/null
+++ b/vendor/google.golang.org/grpc/pickfirst.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 (
+ "errors"
+
+ "google.golang.org/grpc/balancer"
+ "google.golang.org/grpc/codes"
+ "google.golang.org/grpc/connectivity"
+ "google.golang.org/grpc/grpclog"
+ "google.golang.org/grpc/resolver"
+ "google.golang.org/grpc/status"
+)
+
+// 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 {
+ state connectivity.State
+ cc balancer.ClientConn
+ sc balancer.SubConn
+}
+
+var _ balancer.V2Balancer = &pickfirstBalancer{} // Assert we implement v2
+
+func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
+ if err != nil {
+ b.ResolverError(err)
+ return
+ }
+ b.UpdateClientConnState(balancer.ClientConnState{ResolverState: resolver.State{Addresses: addrs}}) // Ignore error
+}
+
+func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+ b.UpdateSubConnState(sc, balancer.SubConnState{ConnectivityState: s})
+}
+
+func (b *pickfirstBalancer) ResolverError(err error) {
+ switch b.state {
+ case connectivity.TransientFailure, connectivity.Idle, connectivity.Connecting:
+ // Set a failing picker if we don't have a good picker.
+ b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
+ Picker: &picker{err: status.Errorf(codes.Unavailable, "name resolver error: %v", err)}},
+ )
+ }
+ if grpclog.V(2) {
+ grpclog.Infof("pickfirstBalancer: ResolverError called with error %v", err)
+ }
+}
+
+func (b *pickfirstBalancer) UpdateClientConnState(cs balancer.ClientConnState) error {
+ if len(cs.ResolverState.Addresses) == 0 {
+ b.ResolverError(errors.New("produced zero addresses"))
+ return balancer.ErrBadResolverState
+ }
+ if b.sc == nil {
+ var err error
+ b.sc, err = b.cc.NewSubConn(cs.ResolverState.Addresses, balancer.NewSubConnOptions{})
+ if err != nil {
+ if grpclog.V(2) {
+ grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+ }
+ b.state = connectivity.TransientFailure
+ b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
+ Picker: &picker{err: status.Errorf(codes.Unavailable, "error creating connection: %v", err)}},
+ )
+ return balancer.ErrBadResolverState
+ }
+ b.state = connectivity.Idle
+ b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.Idle, Picker: &picker{result: balancer.PickResult{SubConn: b.sc}}})
+ b.sc.Connect()
+ } else {
+ b.sc.UpdateAddresses(cs.ResolverState.Addresses)
+ b.sc.Connect()
+ }
+ return nil
+}
+
+func (b *pickfirstBalancer) UpdateSubConnState(sc balancer.SubConn, s balancer.SubConnState) {
+ if grpclog.V(2) {
+ grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+ }
+ if b.sc != sc {
+ if grpclog.V(2) {
+ grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+ }
+ return
+ }
+ b.state = s.ConnectivityState
+ if s.ConnectivityState == connectivity.Shutdown {
+ b.sc = nil
+ return
+ }
+
+ switch s.ConnectivityState {
+ case connectivity.Ready, connectivity.Idle:
+ b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{result: balancer.PickResult{SubConn: sc}}})
+ case connectivity.Connecting:
+ b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{err: balancer.ErrNoSubConnAvailable}})
+ case connectivity.TransientFailure:
+ err := balancer.ErrTransientFailure
+ // TODO: this can be unconditional after the V1 API is removed, as
+ // SubConnState will always contain a connection error.
+ if s.ConnectionError != nil {
+ err = balancer.TransientFailureError(s.ConnectionError)
+ }
+ b.cc.UpdateState(balancer.State{
+ ConnectivityState: s.ConnectivityState,
+ Picker: &picker{err: err},
+ })
+ }
+}
+
+func (b *pickfirstBalancer) Close() {
+}
+
+type picker struct {
+ result balancer.PickResult
+ err error
+}
+
+func (p *picker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
+ return p.result, p.err
+}
+
+func init() {
+ balancer.Register(newPickfirstBuilder())
+}