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Revert "Add a customized ssh dialer that will timeout"

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This commit is contained in:
Wojciech Tyczynski
2016-07-14 08:48:24 +02:00
committed by GitHub
parent f27a8034fd
commit 4b9b1afe76
2 changed files with 50 additions and 51 deletions
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46
pkg/ssh/ssh.go
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@@ -111,7 +111,7 @@ func makeSSHTunnel(user string, signer ssh.Signer, host string) (*SSHTunnel, err
func (s *SSHTunnel) Open() error {
var err error
s.client, err = defaultTimeoutDialer.Dial("tcp", net.JoinHostPort(s.Host, s.SSHPort), s.Config)
s.client, err = realTimeoutDialer.Dial("tcp", net.JoinHostPort(s.Host, s.SSHPort), s.Config)
tunnelOpenCounter.Inc()
if err != nil {
tunnelOpenFailCounter.Inc()
@@ -154,9 +154,21 @@ type sshDialer interface {
Dial(network, addr string, config *ssh.ClientConfig) (*ssh.Client, error)
}
// timeoutDialer implements a Dial() method that will timeout. The golang
// Real implementation of sshDialer
type realSSHDialer struct{}
var _ sshDialer = &realSSHDialer{}
func (d *realSSHDialer) Dial(network, addr string, config *ssh.ClientConfig) (*ssh.Client, error) {
return ssh.Dial(network, addr, config)
}
// timeoutDialer wraps an sshDialer with a timeout around Dial(). The golang
// ssh library can hang indefinitely inside the Dial() call (see issue #23835).
// Wrapping all Dial() calls with a conservative timeout provides safety against
// getting stuck on that.
type timeoutDialer struct {
dialer sshDialer
timeout time.Duration
}
@@ -164,32 +176,30 @@ type timeoutDialer struct {
// seconds). This timeout is only intended to catch otherwise uncaught hangs.
const sshDialTimeout = 150 * time.Second
var defaultTimeoutDialer sshDialer = &timeoutDialer{sshDialTimeout}
var realTimeoutDialer sshDialer = &timeoutDialer{&realSSHDialer{}, sshDialTimeout}
func (d *timeoutDialer) Dial(network, addr string, config *ssh.ClientConfig) (*ssh.Client, error) {
conn, err := net.Dial(network, addr)
if err != nil {
return nil, err
}
conn.SetDeadline(time.Now().Add(d.timeout))
// set to 0 so that conn will not time out after Dial.
defer func() {
conn.SetDeadline(time.Time{})
var client *ssh.Client
errCh := make(chan error, 1)
go func() {
defer runtime.HandleCrash()
var err error
client, err = d.dialer.Dial(network, addr, config)
errCh <- err
}()
// if conn times out, the NewClientConn will close it, so we will not end up
// with hanging goroutines or open file descriptors.
c, chans, reqs, err := ssh.NewClientConn(conn, addr, config)
if err != nil {
return nil, err
select {
case err := <-errCh:
return client, err
case <-time.After(d.timeout):
return nil, fmt.Errorf("timed out dialing %s:%s", network, addr)
}
return ssh.NewClient(c, chans, reqs), nil
}
// RunSSHCommand returns the stdout, stderr, and exit code from running cmd on
// host as specific user, along with any SSH-level error.
// If user=="", it will default (like SSH) to os.Getenv("USER")
func RunSSHCommand(cmd, user, host string, signer ssh.Signer) (string, string, int, error) {
return runSSHCommand(defaultTimeoutDialer, cmd, user, host, signer, true)
return runSSHCommand(realTimeoutDialer, cmd, user, host, signer, true)
}
// Internal implementation of runSSHCommand, for testing