consul lock executes new handler during shutdown

[kazeburo]

I found consul lock executes new handler after receiving SIGINT. Here is log of consul_lock.

[2015-03-19T11:03:39] Shutdown triggered, killing child
[2015-03-19T11:03:39] No child process to kill
[2015-03-19T11:03:39] Starting handler '/usr/local/bin/foo args'
[2015-03-19T11:03:39] Cleanup succeeded

The handler that was executed during shutdown phase remains after consul lock ended.

[armon]

Yikes! Tagged as bug!

[babbottscott]

Issue appears to be https://github.com/hashicorp/consul/blob/master/command/lock.go#L141-L144

If c.ShutdownCh signals, lu.lockFn (either Lock or Acquire) will return 'nil, nil' (https://github.com/hashicorp/consul/blob/master/api/lock.go#L156). This should be instead something like:

if lockCh == nil {
  if err != nil {
     c.Ui.Error(fmt.Sprintf("Lock acquisition failed: %s", err))
  } else {
    c.Ui.Info("Shutdown triggered before lock acquisition")
  }
  return 1
}

[babbottscott]

Also 'return code of 1 for all error states' may be something that could use enhancement.

[babbottscott]

Bump: really needing this one squashed.

[mfischer-zd]

Unfortunately #1080 didn't fix this bug. However it did improve the messaging, so it's still useful.

#1158 should fix it completely.