ValueError: invalid literal for int() with base 10: ' '

[TheEarthlord]

This exception usually comes from the ipbench controller in the process of trying to run a benchmark when ipbenchd on the client has failed to import the python modules ipbench_client and ipbench_target. It happens because the controller tries to connect to the client, but the connection closes immediately due to import failure, while the controller expects an exchange of data. The controller ends up trying to process an empty string since it was given no data, leading to this result.

The solution is twofold:

1. We need to fix the way ipbench packages install ipbench_client and ipbench_target; currently they often end up in places python doesn't check for imports.
2. A simpler stopgap measure is to add checks to the controller and an error message, so that if no data is received it gives an error something like "Connection to ipbenchd was terminated early; check ipbenchd debug output".