govanityurls/vendor/google.golang.org/appengine/internal/net.go
Brandon Philips 26a09c434d
Update to use app engine runtime go112 (#34)
* app.yaml: update to go112

Make the required changes to use go112 due to the deprecation of Go 1.9.

Migration doc:
- https://cloud.google.com/appengine/docs/standard/go111/go-differences

References:
- https://github.com/GoogleCloudPlatform/govanityurls/issues/29#issuecomment-506538041
- https://github.com/etcd-io/maintainers/issues/17

* go.mod: initial commit

Migrate this project to use go.mod and update the README.

This is part of the recommended steps to runtime: go111 and beyond.
https://cloud.google.com/appengine/docs/standard/go111/go-differences

* vendor: add dependent packages

Add all dependencies for the project via vendoring for offline builds.

* travis.yml: drop go 1.6 for 1.12

Go 1.6 is too old to have a number of builtin packages for the latest
appengine package. Remove and update to match app engine version: 1.12.

* appengine.go: remove unused file

From the go111 migration doc:
"The appengine build tag is deprecated and will not be used when
building your app for deployment.  Ensure your code still functions
correctly without it being set."

https://cloud.google.com/appengine/docs/standard/go111/go-differences

* main: respect PORT environment variable

The go111 runtime should use the PORT variable to decide the listening
http port.

"PORT The port that receives HTTP requests."
https://cloud.google.com/appengine/docs/standard/go111/runtime
2020-02-06 09:36:34 -08:00

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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()
}