diff options
Diffstat (limited to 'vendor/google.golang.org/grpc/balancer_conn_wrappers.go')
-rw-r--r-- | vendor/google.golang.org/grpc/balancer_conn_wrappers.go | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go new file mode 100644 index 000000000..11e592aab --- /dev/null +++ b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go @@ -0,0 +1,246 @@ +/* + * + * 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 ( + "fmt" + "sync" + + "google.golang.org/grpc/balancer" + "google.golang.org/grpc/connectivity" + "google.golang.org/grpc/internal/buffer" + "google.golang.org/grpc/internal/channelz" + "google.golang.org/grpc/internal/grpcsync" + "google.golang.org/grpc/resolver" +) + +// scStateUpdate contains the subConn and the new state it changed to. +type scStateUpdate struct { + sc balancer.SubConn + state connectivity.State + err error +} + +// ccBalancerWrapper is a wrapper on top of cc for balancers. +// It implements balancer.ClientConn interface. +type ccBalancerWrapper struct { + cc *ClientConn + balancerMu sync.Mutex // synchronizes calls to the balancer + balancer balancer.Balancer + scBuffer *buffer.Unbounded + done *grpcsync.Event + + mu sync.Mutex + subConns map[*acBalancerWrapper]struct{} +} + +func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper { + ccb := &ccBalancerWrapper{ + cc: cc, + scBuffer: buffer.NewUnbounded(), + done: grpcsync.NewEvent(), + subConns: make(map[*acBalancerWrapper]struct{}), + } + go ccb.watcher() + ccb.balancer = b.Build(ccb, bopts) + return ccb +} + +// watcher balancer functions sequentially, so the balancer can be implemented +// lock-free. +func (ccb *ccBalancerWrapper) watcher() { + for { + select { + case t := <-ccb.scBuffer.Get(): + ccb.scBuffer.Load() + if ccb.done.HasFired() { + break + } + ccb.balancerMu.Lock() + su := t.(*scStateUpdate) + ccb.balancer.UpdateSubConnState(su.sc, balancer.SubConnState{ConnectivityState: su.state, ConnectionError: su.err}) + ccb.balancerMu.Unlock() + case <-ccb.done.Done(): + } + + if ccb.done.HasFired() { + ccb.balancer.Close() + ccb.mu.Lock() + scs := ccb.subConns + ccb.subConns = nil + ccb.mu.Unlock() + for acbw := range scs { + ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain) + } + ccb.UpdateState(balancer.State{ConnectivityState: connectivity.Connecting, Picker: nil}) + return + } + } +} + +func (ccb *ccBalancerWrapper) close() { + ccb.done.Fire() +} + +func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State, err error) { + // When updating addresses for a SubConn, if the address in use is not in + // the new addresses, the old ac will be tearDown() and a new ac will be + // created. tearDown() generates a state change with Shutdown state, we + // don't want the balancer to receive this state change. So before + // tearDown() on the old ac, ac.acbw (acWrapper) will be set to nil, and + // this function will be called with (nil, Shutdown). We don't need to call + // balancer method in this case. + if sc == nil { + return + } + ccb.scBuffer.Put(&scStateUpdate{ + sc: sc, + state: s, + err: err, + }) +} + +func (ccb *ccBalancerWrapper) updateClientConnState(ccs *balancer.ClientConnState) error { + ccb.balancerMu.Lock() + defer ccb.balancerMu.Unlock() + return ccb.balancer.UpdateClientConnState(*ccs) +} + +func (ccb *ccBalancerWrapper) resolverError(err error) { + ccb.balancerMu.Lock() + ccb.balancer.ResolverError(err) + ccb.balancerMu.Unlock() +} + +func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) { + if len(addrs) <= 0 { + return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list") + } + ccb.mu.Lock() + defer ccb.mu.Unlock() + if ccb.subConns == nil { + return nil, fmt.Errorf("grpc: ClientConn balancer wrapper was closed") + } + ac, err := ccb.cc.newAddrConn(addrs, opts) + if err != nil { + return nil, err + } + acbw := &acBalancerWrapper{ac: ac} + acbw.ac.mu.Lock() + ac.acbw = acbw + acbw.ac.mu.Unlock() + ccb.subConns[acbw] = struct{}{} + return acbw, nil +} + +func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) { + acbw, ok := sc.(*acBalancerWrapper) + if !ok { + return + } + ccb.mu.Lock() + defer ccb.mu.Unlock() + if ccb.subConns == nil { + return + } + delete(ccb.subConns, acbw) + ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain) +} + +func (ccb *ccBalancerWrapper) UpdateState(s balancer.State) { + ccb.mu.Lock() + defer ccb.mu.Unlock() + if ccb.subConns == nil { + return + } + // Update picker before updating state. Even though the ordering here does + // not matter, it can lead to multiple calls of Pick in the common start-up + // case where we wait for ready and then perform an RPC. If the picker is + // updated later, we could call the "connecting" picker when the state is + // updated, and then call the "ready" picker after the picker gets updated. + ccb.cc.blockingpicker.updatePicker(s.Picker) + ccb.cc.csMgr.updateState(s.ConnectivityState) +} + +func (ccb *ccBalancerWrapper) ResolveNow(o resolver.ResolveNowOptions) { + ccb.cc.resolveNow(o) +} + +func (ccb *ccBalancerWrapper) Target() string { + return ccb.cc.target +} + +// acBalancerWrapper is a wrapper on top of ac for balancers. +// It implements balancer.SubConn interface. +type acBalancerWrapper struct { + mu sync.Mutex + ac *addrConn +} + +func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) { + acbw.mu.Lock() + defer acbw.mu.Unlock() + if len(addrs) <= 0 { + acbw.ac.tearDown(errConnDrain) + return + } + if !acbw.ac.tryUpdateAddrs(addrs) { + cc := acbw.ac.cc + opts := acbw.ac.scopts + acbw.ac.mu.Lock() + // Set old ac.acbw to nil so the Shutdown state update will be ignored + // by balancer. + // + // TODO(bar) the state transition could be wrong when tearDown() old ac + // and creating new ac, fix the transition. + acbw.ac.acbw = nil + acbw.ac.mu.Unlock() + acState := acbw.ac.getState() + acbw.ac.tearDown(errConnDrain) + + if acState == connectivity.Shutdown { + return + } + + ac, err := cc.newAddrConn(addrs, opts) + if err != nil { + channelz.Warningf(logger, acbw.ac.channelzID, "acBalancerWrapper: UpdateAddresses: failed to newAddrConn: %v", err) + return + } + acbw.ac = ac + ac.mu.Lock() + ac.acbw = acbw + ac.mu.Unlock() + if acState != connectivity.Idle { + ac.connect() + } + } +} + +func (acbw *acBalancerWrapper) Connect() { + acbw.mu.Lock() + defer acbw.mu.Unlock() + acbw.ac.connect() +} + +func (acbw *acBalancerWrapper) getAddrConn() *addrConn { + acbw.mu.Lock() + defer acbw.mu.Unlock() + return acbw.ac +} |