Look at stdout and stderr of k0s etcd member-list separately

[twz123]

Sometimes, random log statements may appear on stderr, which can break the parsing. Try to parse stdout first, then fallback to stderr. Error out if none of both was a JSON document.

An example log line on stderr looks like this:

W0917 07:11:23.255691 3096 logging.go:55] [core] [Channel https://github.com//pull/1 SubChannel https://github.com//pull/2]grpc: addrConn.createTransport failed to connect to {Addr: "127.0.0.1:2379", ServerName: "127.0.0.1:2379", }. Err: connection error: desc = "transport: Error while dialing: dial tcp 127.0.0.1:2379: operation was canceled"

[kke]

Would it be a problem to do it on all versions?

It's also possible to get separate streams with something like:

var stdoutbuf, stderrbuf bytes.Buffer
cmd, err := h.ExecStreams("command", nil, &stdoutbuf, &stderrbuf, exec.Sudo(h)) // first nil is stdin
if err != nil {
  return fmt.Errorf("failed to create command: %w", err)
}
if err := cmd.Wait(); err != nil {
  return fmt.Errorf("command failed: %w", err)
}
// parse stdout, maybe log stderr

[twz123]

Would it be a problem to do it on all versions?

It's also possible to get separate streams with something like:

var stdoutbuf, stderrbuf bytes.Buffer
cmd, err := h.ExecStreams("command", nil, &stdoutbuf, &stderrbuf, exec.Sudo(h)) // first nil is stdin
if err != nil {
  return fmt.Errorf("failed to create command: %w", err)
}
if err := cmd.Wait(); err != nil {
  return fmt.Errorf("command failed: %w", err)
}
// parse stdout, maybe log stderr

Oh, that was the method I was looking for 😅

[laghoule]

I'm currently experiencing it:

INFO ==> Running phase: Gather k0s facts 
INFO [ssh] ctrl-01:22: found existing configuration 
INFO [ssh] ctrl-01:22: is running k0s controller+worker version v1.34.1+k0s.0 
WARN [ssh] ctrl-01:22: the controller+worker node will not schedule regular workloads without toleration for node-role.kubernetes.io/master:NoSchedule unless 'noTaints: true' is set 
INFO [ssh] ctrl-01:22: listing etcd members       
INFO * Running clean-up for phase: Acquire exclusive host lock 
INFO ==> Apply failed                    
FATA apply failed - log file saved to /home/XXX/.cache/k0sctl/k0sctl.log: failed to decode etcd member-list output: invalid character 'W' looking for beginning of value 

[kke]

Maybe a bit overkill to try parsing stderr for json, but sure, why not