/
cached.go
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/
cached.go
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// Copyright 2015 The Serviced 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 rpcutils
import (
"sync"
"time"
)
// RPC_CLIENT_SIZE max number of rpc clients per address
var RPC_CLIENT_SIZE = 1
// RPCCertVerify used to enable server certificate verification
var RPCCertVerify = false
// RPCDisableTLS used to disable TLS connections
var RPCDisableTLS = false
// DiscardClientTimeout timeout for removing client from pool if a call is taking too long. Does not interrupt call.
var DiscardClientTimeout = 30 * time.Second
//map of address to client
var clientCache = make(map[string]Client)
var cacheLock = sync.RWMutex{}
var addrLocks = make(map[string]*sync.RWMutex)
// Client for calling rpc methods
type Client interface {
Close() error
// TODO: CHANGE TIMEOUT TO MILLISECONDS, NOT SECONDS
Call(serviceMethod string, args interface{}, reply interface{}, timeout time.Duration) error
}
// GetCachedClient createa or gets a cached Client.
func GetCachedClient(addr string) (Client, error) {
return getClient(addr)
}
func getClient(addr string) (Client, error) {
if _, found := localAddrs[addr]; found {
return localRpcClient, nil
}
addrLock := getAddrLock(addr)
addrLock.RLock()
client, found := clientCache[addr]
addrLock.RUnlock()
if !found {
return setAndGetClient(addr)
}
return client, nil
}
func getAddrLock(addr string) *sync.RWMutex {
cacheLock.RLock()
addrLock, found := addrLocks[addr]
cacheLock.RUnlock()
if !found {
cacheLock.Lock()
defer cacheLock.Unlock()
if addrLock, found = addrLocks[addr]; !found {
addrLock = &sync.RWMutex{}
addrLocks[addr] = addrLock
}
}
return addrLock
}
func setAndGetClient(addr string) (Client, error) {
var err error
addrLock := getAddrLock(addr)
addrLock.Lock()
defer addrLock.Unlock()
client, found := clientCache[addr]
if !found {
connFn := connectRPCTLS
if RPCDisableTLS {
connFn = connectRPC
}
client, err = newClient(addr, RPC_CLIENT_SIZE, DiscardClientTimeout, connFn)
if err != nil {
return nil, err
}
clientCache[addr] = client
}
return client, nil
}