mirror of https://github.com/grpc/grpc-go.git
116 lines
3.2 KiB
Go
116 lines
3.2 KiB
Go
/*
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*
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* Copyright 2020 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 xdsclient
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import (
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"fmt"
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"sync"
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"sync/atomic"
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"time"
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"google.golang.org/grpc/internal/envconfig"
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"google.golang.org/grpc/internal/grpcsync"
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"google.golang.org/grpc/internal/xds/bootstrap"
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)
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const (
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defaultWatchExpiryTimeout = 15 * time.Second
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defaultIdleAuthorityDeleteTimeout = 5 * time.Minute
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)
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var (
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// This is the client returned by New(). It contains one client implementation,
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// and maintains the refcount.
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singletonMu sync.Mutex
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singletonClient *clientRefCounted
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// The following functions are no-ops in the actual code, but can be
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// overridden in tests to give them visibility into certain events.
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singletonClientImplCreateHook = func() {}
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singletonClientImplCloseHook = func() {}
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)
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// To override in tests.
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var bootstrapNewConfig = bootstrap.NewConfig
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func clientRefCountedClose() {
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singletonMu.Lock()
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defer singletonMu.Unlock()
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if singletonClient.decrRef() != 0 {
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return
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}
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singletonClient.clientImpl.close()
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singletonClientImplCloseHook()
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singletonClient = nil
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}
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func newRefCountedWithConfig(fallbackConfig *bootstrap.Config) (XDSClient, func(), error) {
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singletonMu.Lock()
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defer singletonMu.Unlock()
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if singletonClient != nil {
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singletonClient.incrRef()
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return singletonClient, grpcsync.OnceFunc(clientRefCountedClose), nil
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}
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// Use fallbackConfig only if bootstrap env vars are unspecified.
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var config *bootstrap.Config
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if envconfig.XDSBootstrapFileName == "" && envconfig.XDSBootstrapFileContent == "" {
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if fallbackConfig == nil {
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return nil, nil, fmt.Errorf("xds: bootstrap env vars are unspecified and provided fallback config is nil")
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}
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config = fallbackConfig
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} else {
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var err error
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config, err = bootstrapNewConfig()
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if err != nil {
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return nil, nil, fmt.Errorf("xds: failed to read bootstrap file: %v", err)
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}
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}
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// Create the new client implementation.
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c, err := newWithConfig(config, defaultWatchExpiryTimeout, defaultIdleAuthorityDeleteTimeout)
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if err != nil {
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return nil, nil, err
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}
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singletonClient = &clientRefCounted{clientImpl: c, refCount: 1}
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singletonClientImplCreateHook()
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logger.Infof("xDS node ID: %s", config.NodeProto.GetId())
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return singletonClient, grpcsync.OnceFunc(clientRefCountedClose), nil
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}
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// clientRefCounted is ref-counted, and to be shared by the xds resolver and
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// balancer implementations, across multiple ClientConns and Servers.
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type clientRefCounted struct {
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*clientImpl
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refCount int32 // accessed atomically
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}
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func (c *clientRefCounted) incrRef() int32 {
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return atomic.AddInt32(&c.refCount, 1)
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}
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func (c *clientRefCounted) decrRef() int32 {
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return atomic.AddInt32(&c.refCount, -1)
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}
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