Using ...pods.exec.post() results in Error: Upgrade request required

[fefl]

I am currently trying to use client.api.v1.namespaces(ns).pods(pod).exec.post() to run a command in a pod. Using it looks something like this:

const cmd = await client.api.v1.namespaces(ns).pods(pod).exec.post({ qs: { command: ['nginx', '-s', 'reload'] } });

This results in the following error:

{ Error: Upgrade request required
    at http.request (/app/node_modules/fluent-openapi/lib/loader.js:230:25)
    at Request.request [as _callback] (/app/node_modules/kubernetes-client/lib/request.js:107:14)
    at Request.self.callback (/app/node_modules/request/request.js:185:22)
    at Request.emit (events.js:180:13)
    at Request.<anonymous> (/app/node_modules/request/request.js:1161:10)
    at Request.emit (events.js:180:13)
    at IncomingMessage.<anonymous> (/app/node_modules/request/request.js:1083:12)
    at Object.onceWrapper (events.js:272:13)
    at IncomingMessage.emit (events.js:185:15)
    at endReadableNT (_stream_readable.js:1101:12)
    at process._tickCallback (internal/process/next_tick.js:114:19) code: 400, statusCode: 400 }

This error occurs with Kubernetes v1.9.0 as well as with v1.9.4 and v1.9.5. I used version 6.0.0 of your client.

If there is any more information I can provide you to help me solve this just tell me.

[silasbw]

kubernetes-client doesn't exec, but it would be nice if it did. it's been on the TODO list for a long time.

This issue discussing how to use exec in node.js might be helpful to you: #19

[gempesaw]

Oh, this reminds me, I found a blog post and looked at the Kube server code to see how the Kube API wanted to talk over the websocket channel for the seemingly undocumented exec endpoint. It wants websocket frames where the first byte indicates the stream (stdout/stderr/....something else/out of band-errors) and then the rest of the frame is the command as binary.

I'm happy to open a PR for it, but I don't know what kind of interface kubernetes-client would like to present around the functionality. Like - when you call exec, it returns a websocket connection that you can pass commands to? or just these one-off "execute a command and get a string result back"? Also, I believe it'd require an additional websocket library dependency, if that's a concern...

[silasbw]

It would be rad to support this somehow because we get a bunch of questions about it.

One incremental way to add support is to handle the upgrade response in exec.post (and actually retry the request with the websocket), and then add something to examples/ that shows how to execute commands using exec.post like you describe above @gempesaw.

That's probably the minimum amount of support in kubernetes-client to actually support exec. We could see how that flies with users, and then decide what to do next based on that feedback. Thoughts @gempesaw? I think folks would be super happy if you contributed some exec support.

[gempesaw]

Cool, that sounds like an entirely reasonable first step. I hope to take a look this weekend :)

[gempesaw]

@silasbw hey, where would you expect this functionality to live? if i'm understanding the structure correctly, I'd guess it it belongs in fluent-openapi... as special logic in the post function?

I don't think I can express it as part of a swagger spec - last I checked swagger didn't have built in support for websockets...

[silasbw]

What if we add code here-ish and handle it in a way similar to 401ing:

https://github.com/godaddy/kubernetes-client/blob/master/lib/request.js#L94

If the response has an upgrade header, we upgrade the connection and retry. We might be able to handle that way without adding endpoint specific logic.

[Stumblinbear]

Currently using this bit of code for the functionality, however while commands are instantly executed, it doesn't actually close the socket for ~30 seconds. Not sure why, but it works for now.

async exec(...cmds: string[]) {
    return new Promise((resolve, reject) => {
        var response = '', uri = '';

        uri += 'wss://';
        // Create the URL from config data
        uri += this.client.kConfig.url.split('://', 2)[1];
        // Fetch the raw url from the exec endpoint
        uri += '/' + (client.k.api.v1.namespaces(ns).pod(cmdPod) as any)['splits'].join('/');
        uri += '?stdout=1&stdin=1&stderr=1';

        let newCmds = ['/bin/bash', '-c', '$(' + cmds.join(') && (') + ')'];
        newCmds.forEach(subCmd => uri += `&command=${encodeURIComponent(subCmd)}`);
    
        var ws = new WebSocket(uri, 'base64.channel.k8s.io', {
            ca: this.kConfig.ca,
            key: this.kConfig.key,
            cert: this.kConfig.cert
        });

        ws.on('message', function(data: any) {
            if(data[0].match(/^[0-3]$/)) {
                response += Buffer.from(data.slice(1), 'base64').toString('ascii');
            }
        });

        ws.on('error', (err: Error) => reject(err));
        ws.on('close', () => resolve(response));
    });
}