How to cancel a SPDYExecutor stream?

[rberrelleza]

I'm executing a long-running command on a pod with the following code:

exec, err := remotecommand.NewSPDYExecutor(config, method, url)
	if err != nil {
		return err
	}

	return exec.Stream(remotecommand.StreamOptions{
		Stdin:             stdin,
		Stdout:            stdout,
		Stderr:            stderr,
		Tty:               tty,
		TerminalSizeQueue: terminalSizeQueue,
	})

In this implementation, exec.Stream won't return until the command finishes.

How can I cancel the call to Executor.Stream? (e.g. to react to a cancellation context, or to initiate a shutdown sequence). I searched in the docs and the code base but couldn't figure out a way to pass a context, a cancel function or something similar.

[djgilcrease]

I have found that as soon as stdin is closed it will return. Though I also found this to be inconsistent and just switched to GetLogs and updated my containers that used to expect stdin to read from an env var that I pass into the POD when starting it.

https://gitlab.com/f5-pwe/kog/blob/master/executor.k8s.go#L197

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[phanhuyn]

@rberrelleza do you find the solution to this?
I've tried closing stdin/stdout/stderr stream, the Executor.Stream() will stuck here because of empty error chan

[rberrelleza]

@rberrelleza do you find the solution to this?
I've tried closing stdin/stdout/stderr stream, the Executor.Stream() will stuck here because of empty error chan

no, the proposed solution didn't work for me. I ended up launching the connection on a goroutine so it wouldn't block the rest, and just time it out if needed.

[wangjia184]

You can set TTY to true, and send CTRL-C(0x03) to stdin

[hainesc]

I send CTRL-D(0x04) to close it.

[zhamdoctor]

0x04

write message with ctrl-d or 0x04?

[liukelin]

How to with ctrl-d or 0x04?

[zhamdoctor]

How to with ctrl-d or 0x04?

exit command from frontend,but it cant resolve the situation like vpn disconnection unexpectly.you can restore pid locally and send kill command next time the user log in the same pod

[liukelin]

请问下。我用了client-go 的新版本，提供了 StreamWithContext函数，可以通过监听前端websocket关闭，来同时控制关闭这个context。这样 Stream流倒是关闭了， 但是我发现pod里面的sh进程还存在。 不知道怎么发送 ctrl-d or 0x04，有例子吗。

[CirillaQL]

请问下。我用了client-go 的新版本，提供了 StreamWithContext函数，可以通过监听前端websocket关闭，来同时控制关闭这个context。这样 Stream流倒是关闭了， 但是我发现pod里面的sh进程还存在。 不知道怎么发送 ctrl-d or 0x04，有例子吗。

参考这个pr kubesphere/kubesphere#5024 在关闭时向流中写入0x04，但是还是有上面说的问题，如果网络异常，无法发送该信号到容器中；或者在容器中sh又执行bash，那0x04只会关闭最外层的shell，还是会导致有sh进程泄露。

[liukelin]

有其他好的实现吗，确实还是会sh进程泄露。不知道是不是0x04没发送成的问题

[CirillaQL]

有其他好的实现吗，确实还是会sh进程泄露。不知道是不是0x04没发送成的问题

如果只有一层shell进程，网络正常的话，0x04是好用的，我已经在我们的环境上测试完成了。

[liukelin]

是直接在这个函数里面写吗
Read(p []byte) (size int, err error)

[CirillaQL]

kubesphere/kubesphere#5024

是的，看pr的terminal.go文件修改内容呀，在需要的退出位置 copy(p, '\u0004')
kubesphere/kubesphere#5024