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hang-fds.go
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hang-fds.go
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package main
import (
"flag"
"fmt"
"io"
"os"
"strconv"
"time"
ma "github.com/multiformats/go-multiaddr"
manet "github.com/multiformats/go-multiaddr-net"
)
var usageText = `usage: %s <fd-num> <multiaddr>
open <fd-num> file descriptors at <multiaddr>, and keep them open
until the process is killed. This command useful for test suites.
For example:
# open 16 tcp sockets at 127.0.0.1:80
%s 16 /ip4/127.0.0.1/tcp/80
`
// TODO:
// # open 64 utp sockets at 127.0.0.1:8080
// %s 64 /ip4/127.0.0.1/udp/8080/utp
// # open 1024 unix domain sockets at /foo/var.sock
// %s 1024 /uds/foo/var.sock
func readUntilErr(r io.Reader) error {
buf := make([]byte, 1024)
for {
_, err := r.Read(buf)
if err != nil {
return err
}
}
}
func dialAndHang(i int, m ma.Multiaddr, errs chan<- error) {
c, err := manet.Dial(m)
if err != nil {
errs <- err
return
}
fmt.Printf("conn %d connected\n", i)
// read until proc exits or conn closes.
go func() {
errs <- readUntilErr(c)
}()
}
func fdHang(n int, m ma.Multiaddr, hold time.Duration) error {
// first, make sure we raise our own fds to be enough.
if err := fdRaise(n + 20); err != nil {
return err
}
errs := make(chan error, n)
for i := 0; i < n; i++ {
// this sleep is here because OSX fails to be able to dial and listen
// as fast as Go tries to issue the commands. this seems to be a crap
// os failure.
time.Sleep(time.Millisecond)
dialAndHang(i, m, errs)
}
var deadline <-chan time.Time
if hold != 0 {
deadline = time.After(hold)
}
var lastErr error
for i := 0; i < n; i++ {
select {
case err := <-errs:
if err != nil && err != io.EOF {
fmt.Printf("conn %d error: %s\n", i, err)
lastErr = err
}
case <-deadline:
fmt.Println("times up! exiting...")
return lastErr
}
}
fmt.Println("done")
return lastErr
}
func fatal(i interface{}) {
fmt.Println(i)
os.Exit(1)
}
func main() {
flag.Usage = func() {
p := os.Args[0]
fmt.Printf(usageText, p, p)
}
hold := flag.String("hold", "0", "time to hold connections open for (0 implies forever)")
flag.Parse()
if len(flag.Args()) != 2 {
flag.Usage()
os.Exit(1)
return
}
n, err := strconv.Atoi(flag.Args()[0])
if err != nil {
fatal("<fd-num> argument must be a number")
}
m, err := ma.NewMultiaddr(flag.Args()[1])
if err != nil {
fatal("<multiaddr> argument must be a valid multiaddr")
}
var holddur time.Duration
if *hold != "0" {
dur, err := time.ParseDuration(*hold)
if err != nil {
fatal(err)
}
holddur = dur
}
fmt.Printf("hanging %d fds at %s\n", n, m)
if err := fdHang(n, m, holddur); err != nil {
fatal(err)
}
}