mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-15 08:23:34 +01:00
230 lines
6.3 KiB
Go
230 lines
6.3 KiB
Go
/*
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*
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* Copyright 2017 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package grpc
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import (
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"context"
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"fmt"
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"io"
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"sync"
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"google.golang.org/grpc/balancer"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/grpclog"
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"google.golang.org/grpc/internal/channelz"
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"google.golang.org/grpc/internal/transport"
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"google.golang.org/grpc/status"
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)
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// v2PickerWrapper wraps a balancer.Picker while providing the
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// balancer.V2Picker API. It requires a pickerWrapper to generate errors
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// including the latest connectionError. To be deleted when balancer.Picker is
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// updated to the balancer.V2Picker API.
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type v2PickerWrapper struct {
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picker balancer.Picker
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connErr *connErr
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}
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func (v *v2PickerWrapper) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
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sc, done, err := v.picker.Pick(info.Ctx, info)
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if err != nil {
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if err == balancer.ErrTransientFailure {
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return balancer.PickResult{}, balancer.TransientFailureError(fmt.Errorf("%v, latest connection error: %v", err, v.connErr.connectionError()))
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}
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return balancer.PickResult{}, err
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}
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return balancer.PickResult{SubConn: sc, Done: done}, nil
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}
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// pickerWrapper is a wrapper of balancer.Picker. It blocks on certain pick
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// actions and unblock when there's a picker update.
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type pickerWrapper struct {
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mu sync.Mutex
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done bool
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blockingCh chan struct{}
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picker balancer.V2Picker
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// The latest connection error. TODO: remove when V1 picker is deprecated;
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// balancer should be responsible for providing the error.
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*connErr
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}
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type connErr struct {
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mu sync.Mutex
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err error
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}
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func (c *connErr) updateConnectionError(err error) {
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c.mu.Lock()
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c.err = err
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c.mu.Unlock()
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}
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func (c *connErr) connectionError() error {
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c.mu.Lock()
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err := c.err
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c.mu.Unlock()
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return err
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}
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func newPickerWrapper() *pickerWrapper {
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return &pickerWrapper{blockingCh: make(chan struct{}), connErr: &connErr{}}
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}
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// updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
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func (pw *pickerWrapper) updatePicker(p balancer.Picker) {
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pw.updatePickerV2(&v2PickerWrapper{picker: p, connErr: pw.connErr})
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}
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// updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
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func (pw *pickerWrapper) updatePickerV2(p balancer.V2Picker) {
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pw.mu.Lock()
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if pw.done {
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pw.mu.Unlock()
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return
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}
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pw.picker = p
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// pw.blockingCh should never be nil.
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close(pw.blockingCh)
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pw.blockingCh = make(chan struct{})
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pw.mu.Unlock()
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}
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func doneChannelzWrapper(acw *acBalancerWrapper, done func(balancer.DoneInfo)) func(balancer.DoneInfo) {
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acw.mu.Lock()
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ac := acw.ac
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acw.mu.Unlock()
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ac.incrCallsStarted()
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return func(b balancer.DoneInfo) {
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if b.Err != nil && b.Err != io.EOF {
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ac.incrCallsFailed()
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} else {
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ac.incrCallsSucceeded()
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}
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if done != nil {
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done(b)
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}
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}
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}
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// pick returns the transport that will be used for the RPC.
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// It may block in the following cases:
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// - there's no picker
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// - the current picker returns ErrNoSubConnAvailable
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// - the current picker returns other errors and failfast is false.
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// - the subConn returned by the current picker is not READY
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// When one of these situations happens, pick blocks until the picker gets updated.
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func (pw *pickerWrapper) pick(ctx context.Context, failfast bool, info balancer.PickInfo) (transport.ClientTransport, func(balancer.DoneInfo), error) {
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var ch chan struct{}
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var lastPickErr error
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for {
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pw.mu.Lock()
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if pw.done {
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pw.mu.Unlock()
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return nil, nil, ErrClientConnClosing
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}
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if pw.picker == nil {
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ch = pw.blockingCh
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}
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if ch == pw.blockingCh {
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// This could happen when either:
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// - pw.picker is nil (the previous if condition), or
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// - has called pick on the current picker.
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pw.mu.Unlock()
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select {
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case <-ctx.Done():
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var errStr string
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if lastPickErr != nil {
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errStr = "latest balancer error: " + lastPickErr.Error()
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} else if connectionErr := pw.connectionError(); connectionErr != nil {
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errStr = "latest connection error: " + connectionErr.Error()
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} else {
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errStr = ctx.Err().Error()
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}
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switch ctx.Err() {
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case context.DeadlineExceeded:
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return nil, nil, status.Error(codes.DeadlineExceeded, errStr)
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case context.Canceled:
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return nil, nil, status.Error(codes.Canceled, errStr)
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}
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case <-ch:
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}
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continue
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}
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ch = pw.blockingCh
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p := pw.picker
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pw.mu.Unlock()
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pickResult, err := p.Pick(info)
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if err != nil {
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if err == balancer.ErrNoSubConnAvailable {
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continue
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}
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if tfe, ok := err.(interface{ IsTransientFailure() bool }); ok && tfe.IsTransientFailure() {
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if !failfast {
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lastPickErr = err
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continue
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}
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return nil, nil, status.Error(codes.Unavailable, err.Error())
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}
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if _, ok := status.FromError(err); ok {
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return nil, nil, err
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}
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// err is some other error.
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return nil, nil, status.Error(codes.Unknown, err.Error())
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}
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acw, ok := pickResult.SubConn.(*acBalancerWrapper)
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if !ok {
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grpclog.Error("subconn returned from pick is not *acBalancerWrapper")
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continue
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}
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if t, ok := acw.getAddrConn().getReadyTransport(); ok {
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if channelz.IsOn() {
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return t, doneChannelzWrapper(acw, pickResult.Done), nil
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}
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return t, pickResult.Done, nil
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}
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if pickResult.Done != nil {
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// Calling done with nil error, no bytes sent and no bytes received.
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// DoneInfo with default value works.
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pickResult.Done(balancer.DoneInfo{})
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}
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grpclog.Infof("blockingPicker: the picked transport is not ready, loop back to repick")
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// If ok == false, ac.state is not READY.
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// A valid picker always returns READY subConn. This means the state of ac
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// just changed, and picker will be updated shortly.
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// continue back to the beginning of the for loop to repick.
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}
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}
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func (pw *pickerWrapper) close() {
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pw.mu.Lock()
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defer pw.mu.Unlock()
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if pw.done {
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return
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}
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pw.done = true
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close(pw.blockingCh)
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}
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