race condition between weave launch and the next command

[bboreham]

The weave container process starts up asynchronously, so when weave launch returns, weave may not actually be ready to accept the next command.

This has been observed when the next command uses http, e.g. a weave status or weave connect. The symptom in this case is a silent exit with exitcode 7, which comes from the curl command when it cannot contact weave's http port.

One option would be to call weave status at the end of weave launch, looping a few times until we get an answer. This would also give better error reporting in the case that weave launch has failed, e.g. due to an error in the command-line syntax.

[bboreham]

I have implemented my suggestion in b256555 (on another branch)

[bboreham]

Sadly that had a bug, fixed in bboreham@f19cf7db5