mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-26 23:10:22 +00:00
57 lines
1.2 KiB
Go
57 lines
1.2 KiB
Go
// Copyright 2014 Google Inc. All rights reserved.
|
|
// Use of this source code is governed by the Apache 2.0
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package internal
|
|
|
|
// This file implements a network dialer that limits the number of concurrent connections.
|
|
// It is only used for API calls.
|
|
|
|
import (
|
|
"log"
|
|
"net"
|
|
"runtime"
|
|
"sync"
|
|
"time"
|
|
)
|
|
|
|
var limitSem = make(chan int, 100) // TODO(dsymonds): Use environment variable.
|
|
|
|
func limitRelease() {
|
|
// non-blocking
|
|
select {
|
|
case <-limitSem:
|
|
default:
|
|
// This should not normally happen.
|
|
log.Print("appengine: unbalanced limitSem release!")
|
|
}
|
|
}
|
|
|
|
func limitDial(network, addr string) (net.Conn, error) {
|
|
limitSem <- 1
|
|
|
|
// Dial with a timeout in case the API host is MIA.
|
|
// The connection should normally be very fast.
|
|
conn, err := net.DialTimeout(network, addr, 500*time.Millisecond)
|
|
if err != nil {
|
|
limitRelease()
|
|
return nil, err
|
|
}
|
|
lc := &limitConn{Conn: conn}
|
|
runtime.SetFinalizer(lc, (*limitConn).Close) // shouldn't usually be required
|
|
return lc, nil
|
|
}
|
|
|
|
type limitConn struct {
|
|
close sync.Once
|
|
net.Conn
|
|
}
|
|
|
|
func (lc *limitConn) Close() error {
|
|
defer lc.close.Do(func() {
|
|
limitRelease()
|
|
runtime.SetFinalizer(lc, nil)
|
|
})
|
|
return lc.Conn.Close()
|
|
}
|