grpc-go/xds/internal/xdsclient/client_refcounted.go

105 lines
3.0 KiB
Go

/*
*
* 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/atomic"
"time"
"google.golang.org/grpc/internal/grpcsync"
"google.golang.org/grpc/internal/xds/bootstrap"
)
const (
defaultWatchExpiryTimeout = 15 * time.Second
defaultIdleAuthorityDeleteTimeout = 5 * time.Minute
)
var (
// The following functions are no-ops in the actual code, but can be
// overridden in tests to give them visibility into certain events.
xdsClientImplCreateHook = func(name string) {}
xdsClientImplCloseHook = func(name string) {}
)
func clientRefCountedClose(name string) {
clientsMu.Lock()
defer clientsMu.Unlock()
client, ok := clients[name]
if !ok {
logger.Errorf("Attempt to close a non-existent xDS client with name %s", name)
return
}
if client.decrRef() != 0 {
return
}
client.clientImpl.close()
xdsClientImplCloseHook(name)
delete(clients, name)
}
// newRefCounted creates a new reference counted xDS client implementation for
// name, if one does not exist already. If an xDS client for the given name
// exists, it gets a reference to it and returns it.
func newRefCounted(name string, watchExpiryTimeout, idleAuthorityTimeout time.Duration) (XDSClient, func(), error) {
clientsMu.Lock()
defer clientsMu.Unlock()
if c := clients[name]; c != nil {
c.incrRef()
return c, grpcsync.OnceFunc(func() { clientRefCountedClose(name) }), nil
}
// Create the new client implementation.
config, err := bootstrap.GetConfiguration()
if err != nil {
return nil, nil, fmt.Errorf("xds: failed to get xDS bootstrap config: %v", err)
}
c, err := newClientImpl(config, watchExpiryTimeout, idleAuthorityTimeout)
if err != nil {
return nil, nil, err
}
c.logger.Infof("Created client with name %q and bootstrap configuration:\n %s", name, config)
client := &clientRefCounted{clientImpl: c, refCount: 1}
clients[name] = client
xdsClientImplCreateHook(name)
logger.Infof("xDS node ID: %s", config.Node().GetId())
return client, grpcsync.OnceFunc(func() { clientRefCountedClose(name) }), 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)
}