gotosocial/vendor/google.golang.org/appengine/internal/net.go
Tobi Smethurst 98263a7de6
Grand test fixup (#138)
* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig
2021-08-12 21:03:24 +02:00

56 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, 10*time.Second)
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()
}