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